Patent Publication Number: US-2022232043-A1

Title: Applying application layer policy to transport layer security requests systems and methods

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is a continuation of and claims priority to and the benefit of U.S. Non-Provisional application Ser. No. 16/203,120, titled “APPLYING APPLICATION LAYER POLICY TO TRANSPORT LAYER SECURITY REQUESTS SYSTEMS AND METHODS,” and filed on Nov. 28, 2018, the entire contents of which are herein incorporated by reference in its entirety. 
    
    
     BACKGROUND 
     In many server deployments, users transmit sensitive or encrypted data over a network to a server. The transmission can be maliciously or fraudulently repeated or delayed in the form of a replay attack. For example, two or more identical copies of a request may be processed if the requests arrive at different servers. Thus, in many server deployments, it can become increasingly difficult to determine which client requests have been seen before. Many server protocols may not provide sufficient protection against a network attacker who makes a copy of the client request and replays it to the server at a later time. 
     SUMMARY 
     Systems and methods for applying an application layer policy to a transport layer security request are provided. A device can be disposed intermediary to one or more clients and one or more servers to proxy requests for resources provided by the one or more servers and requested by the one or more client devices. The device (e.g., proxy server) can include a transport layer security (TLS) server and a policy engine to selectively allow or reject early data request processing dynamically for requests received from one or more client devices. The requests can include a TLS request and an application layer request for a resource provided by the one or more servers. The device can apply application layer policies to the application layer request to determine whether to allow or reject early data requests for the resource indicated in the application layer request. In some embodiments, the application layer policy can indicate that the requested resource is replay-safe and include a policy to allow early data processing the respective resource. In some embodiments, the application layer policy can indicate that the requested resource is not replay-safe and include a policy to reject or disallow early data processing the respective resource. Thus, the device can provide protection for the one or more servers (e.g., application servers) from early data replay attacks by proxying TLS requests and application layer requests together. The device can use the application layer policies to provide precise control of speed versus security tradeoffs for early data request processing based at least in part on polices applied to the respective requests. 
     In a first aspect, a method for applying an application layer policy to a transport layer security request is provided. The method can include receiving, by a device intermediary to one or more clients and one or more servers, a transport layer security (TLS) request to establish a TLS connection between a client of the one or more clients and a server of the one or more servers. The TLS request can include an application layer request to a resource of the server. The method can include applying, by the device, an application layer policy to the application layer request of the TLS request. The method can include determining, by the device responsive to applying the application layer policy, whether to one of accept or reject at least the application layer request of the TLS request. 
     In some embodiments, the method can include decrypting, by the device, the application layer request using at least one key included within the TLS request. The method can include identifying, by the device based at least on the TLS request, the application layer policy for accessing the resource. The application layer policy can specify a pattern for matching against at least a portion of the application layer request. The application layer request can include a HyperText Transfer Protocol (HTTP) request. The method can include terminating, at the device, the TLS connection with the client and establishing a communication channel between the device and the server. 
     In some embodiments, the method can include rejecting the application layer request but accepting the TLS request. The method can include omitting, by the device, an extension for early data during a TLS handshake with the client to indicate rejection of the application layer request. In some embodiments, the method can include accepting both the TLS request and the application layer request. The device may include an extension for early data during a TLS handshake with the client to indicate allowing the application layer request. 
     In at least one aspect, a system for applying an application layer policy to a transport layer security request is provided. The system can include a device intermediary to one or more clients and one or more servers. The device can be configured to receive a transport layer security (TLS) request to establish a TLS connection between a client of the one or more clients and a server of the one or more servers. The TLS request can include an application layer request to a resource of the server. The device can be configured to apply an application layer policy to the application layer request of the TLS request and determine responsive to applying the application layer policy, whether to one of accept or reject at least the application layer request of the TLS request. 
     The device can be configured to decrypt the application layer request using at least one key included within the TLS request. The device can be configured to identify, based at least on the TLS request, the application layer policy for accessing the resource. The application layer policy can be configured with a pattern for matching against at least a portion of the application layer request. The application layer request can include a HyperText Transfer Protocol (HTTP) request. The device can be further configured to terminate the TLS connection with the client and establishing a communication channel between the device and the server. 
     In some embodiments, the device can be configured to reject the application layer request but accept the TLS request. The device can be configured to omit an extension for early data during a TLS handshake with the client to indicate rejection of the application layer request. The device can be configured to accept both the TLS request and the application layer request. In some embodiments, the device can be configured to include an extension for early data during a TLS handshake with the client to indicate allowing the application layer request. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING FIGURES 
       Objects, aspects, features, and advantages of embodiments disclosed herein will become more fully apparent from the following detailed description, the appended claims, and the accompanying drawing figures in which like reference numerals identify similar or identical elements. Reference numerals that are introduced in the specification in association with a drawing figure may be repeated in one or more subsequent figures without additional description in the specification in order to provide context for other features, and not every element may be labeled in every figure. The drawing figures are not necessarily to scale, emphasis instead being placed upon illustrating embodiments, principles and concepts. The drawings are not intended to limit the scope of the claims included herewith. 
         FIG. 1A  is a block diagram of a network computing system, in accordance with an illustrative embodiment; 
         FIG. 1B  is a block diagram of a network computing system for delivering a computing environment from a server to a client via an appliance, in accordance with an illustrative embodiment; 
         FIG. 1C  is a block diagram of a computing device, in accordance with an illustrative embodiment; 
         FIG. 2  is a block diagram of an appliance for processing communications between a client and a server, in accordance with an illustrative embodiment; 
         FIG. 3  is a block diagram of a virtualization environment, in accordance with an illustrative embodiment; 
         FIG. 4  is a block diagram of a cluster system, in accordance with an illustrative embodiment; 
         FIG. 5  is a block diagram of a system for applying application layer policy to a transport layer security request; and 
         FIGS. 6A-6B  are a flow diagram of a method for applying application layer policy to a transport layer security request. 
     
    
    
     DETAILED DESCRIPTION 
     For purposes of reading the description of the various embodiments below, the following descriptions of the sections of the specification and their respective contents may be helpful: 
     Section A describes a network environment and computing environment which may be useful for practicing embodiments described herein; and 
     Section B describes embodiments of systems and methods for applying application layer policy to a transport layer security request. 
     A. Network and Computing Environment 
     Referring to  FIG. 1A , an illustrative network environment  100  is depicted. Network environment  100  may include one or more clients  102 ( 1 )- 102 ( n ) (also generally referred to as local machine(s)  102  or client(s)  102 ) in communication with one or more servers  106 ( 1 )- 106 ( n ) (also generally referred to as remote machine(s)  106  or server(s)  106 ) via one or more networks  104 ( 1 )- 104   n  (generally referred to as network(s)  104 ). In some embodiments, a client  102  may communicate with a server  106  via one or more appliances  200 ( 1 )- 200   n  (generally referred to as appliance(s)  200  or gateway(s)  200 ). 
     Although the embodiment shown in  FIG. 1A  shows one or more networks  104  between clients  102  and servers  106 , in other embodiments, clients  102  and servers  106  may be on the same network  104 . The various networks  104  may be the same type of network or different types of networks. For example, in some embodiments, network  104 ( 1 ) may be a private network such as a local area network (LAN) or a company Intranet, while network  104 ( 2 ) and/or network  104 ( n ) may be a public network, such as a wide area network (WAN) or the Internet. In other embodiments, both network  104 ( 1 ) and network  104 ( n ) may be private networks. Networks  104  may employ one or more types of physical networks and/or network topologies, such as wired and/or wireless networks, and may employ one or more communication transport protocols, such as transmission control protocol (TCP), internet protocol (IP), user datagram protocol (UDP) or other similar protocols. 
     As shown in  FIG. 1A , one or more appliances  200  may be located at various points or in various communication paths of network environment  100 . For example, appliance  200  may be deployed between two networks  104 ( 1 ) and  104 ( 2 ), and appliances  200  may communicate with one another to work in conjunction to, for example, accelerate network traffic between clients  102  and servers  106 . In other embodiments, the appliance  200  may be located on a network  104 . For example, appliance  200  may be implemented as part of one of clients  102  and/or servers  106 . In an embodiment, appliance  200  may be implemented as a network device such as NetScaler® products sold by Citrix Systems, Inc. of Fort Lauderdale, Fla. 
     As shown in  FIG. 1A , one or more servers  106  may operate as a server farm  38 . Servers  106  of server farm  38  may be logically grouped, and may either be geographically co-located (e.g., on premises) or geographically dispersed (e.g., cloud based) from clients  102  and/or other servers  106 . In an embodiment, server farm  38  executes one or more applications on behalf of one or more of clients  102  (e.g., as an application server), although other uses are possible, such as a file server, gateway server, proxy server, or other similar server uses. Clients  102  may seek access to hosted applications on servers  106 . 
     As shown in  FIG. 1A , in some embodiments, appliances  200  may include, be replaced by, or be in communication with, one or more additional appliances, such as WAN optimization appliances  205 ( 1 )- 205 ( n ), referred to generally as WAN optimization appliance(s)  205 . For example, WAN optimization appliance  205  may accelerate, cache, compress or otherwise optimize or improve performance, operation, flow control, or quality of service of network traffic, such as traffic to and/or from a WAN connection, such as optimizing Wide Area File Services (WAFS), accelerating Server Message Block (SMB) or Common Internet File System (CIFS). In some embodiments, appliance  205  may be a performance enhancing proxy or a WAN optimization controller. In one embodiment, appliance  205  may be implemented as CloudBridge® products sold by Citrix Systems, Inc. of Fort Lauderdale, Fla. 
     Referring to  FIG. 1B , an example network environment,  100 ′, for delivering and/or operating a computing network environment on a client  102  is shown. As shown in  FIG. 1B , a server  106  may include an application delivery system  190  for delivering a computing environment, application, and/or data files to one or more clients  102 . Client  102  may include client agent  50  and computing environment  15 . Computing environment  15  may execute or operate an application,  16 , that accesses, processes or uses a data file  17 . Computing environment  15 , application  16  and/or data file  17  may be delivered via appliance  200  and/or the server  106 . 
     Appliance  200  may accelerate delivery of all or a portion of computing environment  15  to a client  102 , for example by the application delivery system  190 . For example, appliance  200  may accelerate delivery of a streaming application and data file processable by the application from a data center to a remote user location by accelerating transport layer traffic between a client  102  and a server  106 . Such acceleration may be provided by one or more techniques, such as: 1) transport layer connection pooling, 2) transport layer connection multiplexing, 3) transport control protocol buffering, 4) compression, 5) caching, or other techniques. Appliance  200  may also provide load balancing of servers  106  to process requests from clients  102 , act as a proxy or access server to provide access to the one or more servers  106 , provide security and/or act as a firewall between a client  102  and a server  106 , provide Domain Name Service (DNS) resolution, provide one or more virtual servers or virtual internet protocol servers, and/or provide a secure virtual private network (VPN) connection from a client  102  to a server  106 , such as a secure socket layer (SSL) VPN connection and/or provide encryption and decryption operations. 
     Application delivery management system  190  may deliver computing environment  15  to a user (e.g., client  102 ), remote or otherwise, based on authentication and authorization policies applied by policy engine  195 . A remote user may obtain a computing environment and access to server stored applications and data files from any network-connected device (e.g., client  102 ). For example, appliance  200  may request an application and data file from server  106 . In response to the request, application delivery system  190  and/or server  106  may deliver the application and data file to client  102 , for example via an application stream to operate in computing environment  15  on client  102 , or via a remote-display protocol or otherwise via remote-based or server-based computing. In an embodiment, application delivery system  190  may be implemented as any portion of the Citrix Workspace Suite™ by Citrix Systems, Inc., such as XenApp® or XenDesktop®. 
     Policy engine  195  may control and manage the access to, and execution and delivery of, applications. For example, policy engine  195  may determine the one or more applications a user or client  102  may access and/or how the application should be delivered to the user or client  102 , such as a server-based computing, streaming or delivering the application locally to the client  50  for local execution. 
     For example, in operation, a client  102  may request execution of an application (e.g., application  16 ′) and application delivery system  190  of server  106  determines how to execute application  16 ′, for example based upon credentials received from client  102  and a user policy applied by policy engine  195  associated with the credentials. For example, application delivery system  190  may enable client  102  to receive application-output data generated by execution of the application on a server  106 , may enable client  102  to execute the application locally after receiving the application from server  106 , or may stream the application via network  104  to client  102 . For example, in some embodiments, the application may be a server-based or a remote-based application executed on server  106  on behalf of client  102 . Server  106  may display output to client  102  using a thin-client or remote-display protocol, such as the Independent Computing Architecture (ICA) protocol by Citrix Systems, Inc. of Fort Lauderdale, Fla. The application may be any application related to real-time data communications, such as applications for streaming graphics, streaming video and/or audio or other data, delivery of remote desktops or workspaces or hosted services or applications, for example infrastructure as a service (IaaS), workspace as a service (WaaS), software as a service (SaaS) or platform as a service (PaaS). 
     One or more of servers  106  may include a performance monitoring service or agent  197 . In some embodiments, a dedicated one or more servers  106  may be employed to perform performance monitoring. Performance monitoring may be performed using data collection, aggregation, analysis, management and reporting, for example by software, hardware or a combination thereof. Performance monitoring may include one or more agents for performing monitoring, measurement and data collection activities on clients  102  (e.g., client agent  50 ), servers  106  (e.g., agent  197 ) or an appliance  200  and/or  205  (agent not shown). In general, monitoring agents (e.g.,  50  and/or  197 ) execute transparently (e.g., in the background) to any application and/or user of the device. In some embodiments, monitoring agent  197  includes any of the product embodiments referred to as EdgeSight by Citrix Systems, Inc. of Fort Lauderdale, Fla. 
     The monitoring agents may monitor, measure, collect, and/or analyze data on a predetermined frequency, based upon an occurrence of given event(s), or in real time during operation of network environment  100 . The monitoring agents may monitor resource consumption and/or performance of hardware, software, and/or communications resources of clients  102 , networks  104 , appliances  200  and/or  205 , and/or servers  106 . For example, network connections such as a transport layer connection, network latency, bandwidth utilization, end-user response times, application usage and performance, session connections to an application, cache usage, memory usage, processor usage, storage usage, database transactions, client and/or server utilization, active users, duration of user activity, application crashes, errors, or hangs, the time required to log-in to an application, a server, or the application delivery system, and/or other performance conditions and metrics may be monitored. 
     The monitoring agents may provide application performance management for application delivery system  190 . For example, based upon one or more monitored performance conditions or metrics, application delivery system  190  may be dynamically adjusted, for example periodically or in real-time, to optimize application delivery by servers  106  to clients  102  based upon network environment performance and conditions. 
     In described embodiments, clients  102 , servers  106 , and appliances  200  and  205  may be deployed as and/or executed on any type and form of computing device, such as any desktop computer, laptop computer, or mobile device capable of communication over at least one network and performing the operations described herein. For example, clients  102 , servers  106  and/or appliances  200  and  205  may each correspond to one computer, a plurality of computers, or a network of distributed computers such as computer  101  shown in  FIG. 1C . 
     As shown in  FIG. 1C , computer  101  may include one or more processors  103 , volatile memory  52  (e.g., RAM), non-volatile memory  58  (e.g., one or more hard disk drives (HDDs) or other magnetic or optical storage media, one or more solid state drives (SSDs) such as a flash drive or other solid state storage media, one or more hybrid magnetic and solid state drives, and/or one or more virtual storage volumes, such as a cloud storage, or a combination of such physical storage volumes and virtual storage volumes or arrays thereof), user interface (UI)  53 , one or more communications interfaces  118 , and communication bus  150 . User interface  53  may include graphical user interface (GUI)  54  (e.g., a touchscreen, a display, etc.) and one or more input/output (I/O) devices  56  (e.g., a mouse, a keyboard, etc.). Non-volatile memory  58  stores operating system  115 , one or more applications  116 , and data  117  such that, for example, computer instructions of operating system  115  and/or applications  116  are executed by processor(s)  103  out of volatile memory  52 . Data may be entered using an input device of GUI  54  or received from I/O device(s)  56 . Various elements of computer  101  may communicate via communication bus  150 . Computer  101  as shown in  FIG. 1C  is shown merely as an example, as clients  102 , servers  106  and/or appliances  200  and  205  may be implemented by any computing or processing environment and with any type of machine or set of machines that may have suitable hardware and/or software capable of operating as described herein. 
     Processor(s)  103  may be implemented by one or more programmable processors executing one or more computer programs to perform the functions of the system. As used herein, the term “processor” describes an electronic circuit that performs a function, an operation, or a sequence of operations. The function, operation, or sequence of operations may be hard coded into the electronic circuit or soft coded by way of instructions held in a memory device. A “processor” may perform the function, operation, or sequence of operations using digital values or using analog signals. In some embodiments, the “processor” can be embodied in one or more application specific integrated circuits (ASICs), microprocessors, digital signal processors, microcontrollers, field programmable gate arrays (FPGAs), programmable logic arrays (PLAs), multi-core processors, or general-purpose computers with associated memory. The “processor” may be analog, digital or mixed-signal. In some embodiments, the “processor” may be one or more physical processors or one or more “virtual” (e.g., remotely located or “cloud”) processors. 
     Communications interfaces  118  may include one or more interfaces to enable computer  101  to access a computer network such as a LAN, a WAN, or the Internet through a variety of wired and/or wireless or cellular connections. 
     In described embodiments, a first computing device  101  may execute an application on behalf of a user of a client computing device (e.g., a client  102 ), may execute a virtual machine, which provides an execution session within which applications execute on behalf of a user or a client computing device (e.g., a client  102 ), such as a hosted desktop session, may execute a terminal services session to provide a hosted desktop environment, or may provide access to a computing environment including one or more of: one or more applications, one or more desktop applications, and one or more desktop sessions in which one or more applications may execute. 
     Additional details of the implementation and operation of network environment  100 , clients  102 , servers  106 , and appliances  200  and  205  may be as described in U.S. Pat. No. 9,538,345, issued Jan. 3, 2017 to Citrix Systems, Inc. of Fort Lauderdale, Fla., the teachings of which are hereby incorporated herein by reference. 
       FIG. 2  shows an example embodiment of appliance  200 . As described herein, appliance  200  may be implemented as a server, gateway, router, switch, bridge or other type of computing or network device. As shown in  FIG. 2 , an embodiment of appliance  200  may include a hardware layer  206  and a software layer  205  divided into a user space  202  and a kernel space  204 . Hardware layer  206  provides the hardware elements upon which programs and services within kernel space  204  and user space  202  are executed and allow programs and services within kernel space  204  and user space  202  to communicate data both internally and externally with respect to appliance  200 . As shown in  FIG. 2 , hardware layer  206  may include one or more processing units  262  for executing software programs and services, memory  264  for storing software and data, network ports  266  for transmitting and receiving data over a network, and encryption processor  260  for encrypting and decrypting data such as in relation to Secure Socket Layer (SSL) or Transport Layer Security (TLS) processing of data transmitted and received over the network. 
     An operating system of appliance  200  allocates, manages, or otherwise segregates the available system memory into kernel space  204  and user space  202 . Kernel space  204  is reserved for running kernel  230 , including any device drivers, kernel extensions or other kernel related software. As known to those skilled in the art, kernel  230  is the core of the operating system, and provides access, control, and management of resources and hardware-related elements of application  104 . Kernel space  204  may also include a number of network services or processes working in conjunction with cache manager  232 . 
     Appliance  200  may include one or more network stacks  267 , such as a TCP/IP based stack, for communicating with client(s)  102 , server(s)  106 , network(s)  104 , and/or other appliances  200  or  205 . For example, appliance  200  may establish and/or terminate one or more transport layer connections between clients  102  and servers  106 . Each network stack  267  may include a buffer for queuing one or more network packets for transmission by appliance  200 . 
     Kernel space  204  may include cache manager  232 , packet engine  240 , encryption engine  234 , policy engine  236  and compression engine  238 . In other words, one or more of processes  232 ,  240 ,  234 ,  236  and  238  runs in the core address space of the operating system of appliance  200 , which may reduce the number of data transactions to and from the memory and/or context switches between kernel mode and user mode, for example since data obtained in kernel mode may not need to be passed or copied to a user process, thread or user level data structure. 
     Cache manager  232  may duplicate original data stored elsewhere or data previously computed, generated or transmitted to reducing the access time of the data. In some embodiments, the cache memory may be a data object in memory  264  of appliance  200 , or may be a physical memory having a faster access time than memory  264 . 
     Policy engine  236  may include a statistical engine or other configuration mechanism to allow a user to identify, specify, define or configure a caching policy and access, control and management of objects, data or content being cached by appliance  200 , and define or configure security, network traffic, network access, compression or other functions performed by appliance  200 . 
     Encryption engine  234  may process any security related protocol, such as SSL or TLS. For example, encryption engine  234  may encrypt and decrypt network packets, or any portion thereof, communicated via appliance  200 , may setup or establish SSL, TLS or other secure connections, for example between client  102 , server  106 , and/or other appliances  200  or  205 . In some embodiments, encryption engine  234  may use a tunneling protocol to provide a VPN between a client  102  and a server  106 . In some embodiments, encryption engine  234  is in communication with encryption processor  260 . Compression engine  238  compresses network packets bi-directionally between clients  102  and servers  106  and/or between one or more appliances  200 . 
     Packet engine  240  may manage kernel-level processing of packets received and transmitted by appliance  200  via network stacks  267  to send and receive network packets via network ports  266 . Packet engine  240  may operate in conjunction with encryption engine  234 , cache manager  232 , policy engine  236  and compression engine  238 , for example to perform encryption/decryption, traffic management such as request-level content switching and request-level cache redirection, and compression and decompression of data. 
     User space  202  is a memory area or portion of the operating system used by user mode applications or programs otherwise running in user mode. A user mode application may not access kernel space  204  directly and uses service calls in order to access kernel services. User space  202  may include graphical user interface (GUI)  210 , a command line interface (CLI)  212 , shell services  214 , health monitor  216 , and daemon services  218 . GUI  210  and CLI  212  enable a system administrator or other user to interact with and control the operation of appliance  200 , such as via the operating system of appliance  200 . Shell services  214  include the programs, services, tasks, processes or executable instructions to support interaction with appliance  200  by a user via the GUI  210  and/or CLI  212 . 
     Health monitor  216  monitors, checks, reports and ensures that network systems are functioning properly and that users are receiving requested content over a network, for example by monitoring activity of appliance  200 . In some embodiments, health monitor  216  intercepts and inspects any network traffic passed via appliance  200 . For example, health monitor  216  may interface with one or more of encryption engine  234 , cache manager  232 , policy engine  236 , compression engine  238 , packet engine  240 , daemon services  218 , and shell services  214  to determine a state, status, operating condition, or health of any portion of the appliance  200 . Further, health monitor  216  may determine whether a program, process, service or task is active and currently running, check status, error or history logs provided by any program, process, service or task to determine any condition, status or error with any portion of appliance  200 . Additionally, health monitor  216  may measure and monitor the performance of any application, program, process, service, task or thread executing on appliance  200 . 
     Daemon services  218  are programs that run continuously or in the background and handle periodic service requests received by appliance  200 . In some embodiments, a daemon service may forward the requests to other programs or processes, such as another daemon service  218  as appropriate. 
     As described herein, appliance  200  may relieve servers  106  of much of the processing load caused by repeatedly opening and closing transport layer connections to clients  102  by opening one or more transport layer connections with each server  106  and maintaining these connections to allow repeated data accesses by clients via the Internet (e.g., “connection pooling”). To perform connection pooling, appliance  200  may translate or multiplex communications by modifying sequence numbers and acknowledgment numbers at the transport layer protocol level (e.g., “connection multiplexing”). Appliance  200  may also provide switching or load balancing for communications between the client  102  and server  106 . 
     As described herein, each client  102  may include client agent  50  for establishing and exchanging communications with appliance  200  and/or server  106  via a network  104 . Client  102  may have installed and/or execute one or more applications that are in communication with network  104 . Client agent  50  may intercept network communications from a network stack used by the one or more applications. For example, client agent  50  may intercept a network communication at any point in a network stack and redirect the network communication to a destination desired, managed or controlled by client agent  50 , for example to intercept and redirect a transport layer connection to an IP address and port controlled or managed by client agent  50 . Thus, client agent  50  may transparently intercept any protocol layer below the transport layer, such as the network layer, and any protocol layer above the transport layer, such as the session, presentation or application layers. Client agent  50  can interface with the transport layer to secure, optimize, accelerate, route or load-balance any communications provided via any protocol carried by the transport layer. 
     In some embodiments, client agent  50  is implemented as an Independent Computing Architecture (ICA) client developed by Citrix Systems, Inc. of Fort Lauderdale, Fla. Client agent  50  may perform acceleration, streaming, monitoring, and/or other operations. For example, client agent  50  may accelerate streaming an application from a server  106  to a client  102 . Client agent  50  may also perform end-point detection/scanning and collect end-point information about client  102  for appliance  200  and/or server  106 . Appliance  200  and/or server  106  may use the collected information to determine and provide access, authentication and authorization control of the client&#39;s connection to network  104 . For example, client agent  50  may identify and determine one or more client-side attributes, such as: the operating system and/or a version of an operating system, a service pack of the operating system, a running service, a running process, a file, presence or versions of various applications of the client, such as antivirus, firewall, security, and/or other software. 
     Additional details of the implementation and operation of appliance  200  may be as described in U.S. Pat. No. 9,538,345, issued Jan. 3, 2017 to Citrix Systems, Inc. of Fort Lauderdale, Fla., the teachings of which are hereby incorporated herein by reference. 
     Referring now to  FIG. 3 , a block diagram of a virtualized environment  300  is shown. As shown, a computing device  302  in virtualized environment  300  includes a virtualization layer  303 , a hypervisor layer  304 , and a hardware layer  307 . Hypervisor layer  304  includes one or more hypervisors (or virtualization managers)  301  that allocates and manages access to a number of physical resources in hardware layer  307  (e.g., physical processor(s)  321  and physical disk(s)  328 ) by at least one virtual machine (VM) (e.g., one of VMs  306 ) executing in virtualization layer  303 . Each VM  306  may include allocated virtual resources such as virtual processors  332  and/or virtual disks  342 , as well as virtual resources such as virtual memory and virtual network interfaces. In some embodiments, at least one of VMs  306  may include a control operating system (e.g.,  305 ) in communication with hypervisor  301  and used to execute applications for managing and configuring other VMs (e.g., guest operating systems  310 ) on device  302 . 
     In general, hypervisor(s)  301  may provide virtual resources to an operating system of VMs  306  in any manner that simulates the operating system having access to a physical device. Thus, hypervisor(s)  301  may be used to emulate virtual hardware, partition physical hardware, virtualize physical hardware, and execute virtual machines that provide access to computing environments. In an illustrative embodiment, hypervisor(s)  301  may be implemented as a XEN hypervisor, for example as provided by the open source Xen.org community. In an illustrative embodiment, device  302  executing a hypervisor that creates a virtual machine platform on which guest operating systems may execute is referred to as a host server. In such an embodiment, device  302  may be implemented as a XEN server as provided by Citrix Systems, Inc., of Fort Lauderdale, Fla. 
     Hypervisor  301  may create one or more VMs  306  in which an operating system (e.g., control operating system  305  and/or guest operating system  310 ) executes. For example, the hypervisor  301  loads a virtual machine image to create VMs  306  to execute an operating system. Hypervisor  301  may present VMs  306  with an abstraction of hardware layer  307 , and/or may control how physical capabilities of hardware layer  307  are presented to VMs  306 . For example, hypervisor(s)  301  may manage a pool of resources distributed across multiple physical computing devices. 
     In some embodiments, one of VMs  306  (e.g., the VM executing control operating system  305 ) may manage and configure other of VMs  306 , for example by managing the execution and/or termination of a VM and/or managing allocation of virtual resources to a VM. In various embodiments, VMs may communicate with hypervisor(s)  301  and/or other VMs via, for example, one or more Application Programming Interfaces (APIs), shared memory, and/or other techniques. 
     In general, VMs  306  may provide a user of device  302  with access to resources within virtualized computing environment  300 , for example, one or more programs, applications, documents, files, desktop and/or computing environments, or other resources. In some embodiments, VMs  306  may be implemented as fully virtualized VMs that are not aware that they are virtual machines (e.g., a Hardware Virtual Machine or HVM). In other embodiments, the VM may be aware that it is a virtual machine, and/or the VM may be implemented as a paravirtualized (PV) VM. 
     Although shown in  FIG. 3  as including a single virtualized device  302 , virtualized environment  300  may include a plurality of networked devices in a system in which at least one physical host executes a virtual machine. A device on which a VM executes may be referred to as a physical host and/or a host machine. For example, appliance  200  may be additionally or alternatively implemented in a virtualized environment  300  on any computing device, such as a client  102 , server  106  or appliance  200 . Virtual appliances may provide functionality for availability, performance, health monitoring, caching and compression, connection multiplexing and pooling and/or security processing (e.g., firewall, VPN, encryption/decryption, etc.), similarly as described in regard to appliance  200 . 
     Additional details of the implementation and operation of virtualized computing environment  300  may be as described in U.S. Pat. No. 9,538,345, issued Jan. 3, 2017 to Citrix Systems, Inc. of Fort Lauderdale, Fla., the teachings of which are hereby incorporated herein by reference. 
     In some embodiments, a server may execute multiple virtual machines  306 , for example on various cores of a multi-core processing system and/or various processors of a multiple processor device. For example, although generally shown herein as “processors” (e.g., in  FIGS. 1C, 2 and 3 ), one or more of the processors may be implemented as either single- or multi-core processors to provide a multi-threaded, parallel architecture and/or multi-core architecture. Each processor and/or core may have or use memory that is allocated or assigned for private or local use that is only accessible by that processor/core, and/or may have or use memory that is public or shared and accessible by multiple processors/cores. Such architectures may allow work, task, load or network traffic distribution across one or more processors and/or one or more cores (e.g., by functional parallelism, data parallelism, flow-based data parallelism, etc.). 
     Further, instead of (or in addition to) the functionality of the cores being implemented in the form of a physical processor/core, such functionality may be implemented in a virtualized environment (e.g.,  300 ) on a client  102 , server  106  or appliance  200 , such that the functionality may be implemented across multiple devices, such as a cluster of computing devices, a server farm or network of computing devices, etc. The various processors/cores may interface or communicate with each other using a variety of interface techniques, such as core to core messaging, shared memory, kernel APIs, etc. 
     In embodiments employing multiple processors and/or multiple processor cores, described embodiments may distribute data packets among cores or processors, for example to balance the flows across the cores. For example, packet distribution may be based upon determinations of functions performed by each core, source and destination addresses, and/or whether: a load on the associated core is above a predetermined threshold; the load on the associated core is below a predetermined threshold; the load on the associated core is less than the load on the other cores; or any other metric that can be used to determine where to forward data packets based in part on the amount of load on a processor. 
     For example, data packets may be distributed among cores or processes using receive-side scaling (RSS) in order to process packets using multiple processors/cores in a network. RSS generally allows packet processing to be balanced across multiple processors/cores while maintaining in-order delivery of the packets. In some embodiments, RSS may use a hashing scheme to determine a core or processor for processing a packet. 
     The RSS may generate hashes from any type and form of input, such as a sequence of values. This sequence of values can include any portion of the network packet, such as any header, field or payload of network packet, and include any tuples of information associated with a network packet or data flow, such as addresses and ports. The hash result or any portion thereof may be used to identify a processor, core, engine, etc., for distributing a network packet, for example via a hash table, indirection table, or other mapping technique. 
     Additional details of the implementation and operation of a multi-processor and/or multi-core system may be as described in U.S. Pat. No. 9,538,345, issued Jan. 3, 2017 to Citrix Systems, Inc. of Fort Lauderdale, Fla., the teachings of which are hereby incorporated herein by reference. 
     Although shown in  FIGS. 1A and 1B  as being single appliances, appliances  200  may be implemented as one or more distributed or clustered appliances. Individual computing devices or appliances may be referred to as nodes of the cluster. A centralized management system may perform load balancing, distribution, configuration, or other tasks to allow the nodes to operate in conjunction as a single computing system. Such a cluster may be viewed as a single virtual appliance or computing device.  FIG. 4  shows a block diagram of an illustrative computing device cluster or appliance cluster  400 . A plurality of appliances  200  or other computing devices (e.g., nodes) may be joined into a single cluster  400 . Cluster  400  may operate as an application server, network storage server, backup service, or any other type of computing device to perform many of the functions of appliances  200  and/or  205 . 
     In some embodiments, each appliance  200  of cluster  400  may be implemented as a multi-processor and/or multi-core appliance, as described herein. Such embodiments may employ a two-tier distribution system, with one appliance if the cluster distributing packets to nodes of the cluster, and each node distributing packets for processing to processors/cores of the node. In many embodiments, one or more of appliances  200  of cluster  400  may be physically grouped or geographically proximate to one another, such as a group of blade servers or rack mount devices in a given chassis, rack, and/or data center. In some embodiments, one or more of appliances  200  of cluster  400  may be geographically distributed, with appliances  200  not physically or geographically co-located. In such embodiments, geographically remote appliances may be joined by a dedicated network connection and/or VPN. In geographically distributed embodiments, load balancing may also account for communications latency between geographically remote appliances. 
     In some embodiments, cluster  400  may be considered a virtual appliance, grouped via common configuration, management, and purpose, rather than as a physical group. For example, an appliance cluster may comprise a plurality of virtual machines or processes executed by one or more servers. 
     As shown in  FIG. 4 , appliance cluster  400  may be coupled to a first network  104 ( 1 ) via client data plane  402 , for example to transfer data between clients  102  and appliance cluster  400 . Client data plane  402  may be implemented a switch, hub, router, or other similar network device internal or external to cluster  400  to distribute traffic across the nodes of cluster  400 . For example, traffic distribution may be performed based on equal-cost multi-path (ECMP) routing with next hops configured with appliances or nodes of the cluster, open-shortest path first (OSPF), stateless hash-based traffic distribution, link aggregation (LAG) protocols, or any other type and form of flow distribution, load balancing, and routing. 
     Appliance cluster  400  may be coupled to a second network  104 ( 2 ) via server data plane  404 . Similarly, to client data plane  402 , server data plane  404  may be implemented as a switch, hub, router, or other network device that may be internal or external to cluster  400 . In some embodiments, client data plane  402  and server data plane  404  may be merged or combined into a single device. 
     In some embodiments, each appliance  200  of cluster  400  may be connected via an internal communication network or back plane  406 . Back plane  406  may enable inter-node or inter-appliance control and configuration messages, for inter-node forwarding of traffic, and/or for communicating configuration and control traffic from an administrator or user to cluster  400 . In some embodiments, back plane  406  may be a physical network, a VPN or tunnel, or a combination thereof. 
     Additional details of cluster  400  may be as described in U.S. Pat. No. 9,538,345, issued Jan. 3, 2017 to Citrix Systems, Inc. of Fort Lauderdale, Fla., the teachings of which are hereby incorporated herein by reference. 
     B. Applying an Application Layer Policy to a Transport Layer Security Request 
     The systems and methods described herein can apply an application layer policy to a transport layer security request. A device intermediary to one or more client devices and one or more servers can selectively allow or disable early data request (e.g., transport layer security (TLS) 1.3 requests) processing dynamically for each request. For example, the device can allow or reject early data requests for an application or resource provided by a server based in part on application layer policies generated for the particular application or resource provided by the server. The application layer policies can be generated to provide precise control of speed versus security tradeoffs for early data request processing based at least in part on polices applied to the respective requests. 
     In some embodiments, the device can process TLS data and application data (e.g., HTTP application data) together to combine the full flexibility of application-layer request-based policy rules with a TLS-layer early data control mechanism. Thus, application servers do not have to be modified to get the full benefit of TLS early data features (e.g., TLS 1.3&#39;s 0-RTT early data feature), yet the application servers can remain protected from early data replay attacks through use of the proxy device intermediary to the clients and application servers. 
     The device (e.g., proxy device) can include a TLS server (or TLS proxy) and a policy engine (e.g., HTTP policy engine). The device can process TLS requests and application requests received by one or more client devices. For example, a TLS request from the one or more client devices can include an application layer request for an application or resource provided by at least one server. In some embodiments, the device can proxy HTTP application requests to a backend HTTP application server. For example, the device can process the TLS and HTTP layers of an application request together before either forwarding the HTTP request to the application server or dropping the HTTP request (e.g., rejecting the application layer request). 
     The policy engine of the device can include one or more application-level policies for determining whether to accept or reject a request. In some embodiments, the device (e.g., proxy) can inspect application layer requests in the HTTP layer, yet takes conditional action according to the configured policy in the TLS layer (e.g., to either allow or disallow the early data request from being processed by an application server). For example, if the HTTP request for a resource matches a particular pattern (e.g., request URI matches a particular string) and the particular pattern has been identified using at least one application layer policy as a request to reject, the device can use the TLS layer to reject the early data request. The application layer policy can indicate that access to the resource or application is not replay-safe, for example, and instruct the device to reject early data requests for the resource or application (e.g., HTTP application). The application layer policies can be generated by an administrator of the device, by the device, an administrator of the application server, and/or the application server. 
     In some embodiments, the rejection of the early data can occur in the TLS layer when an “early_data” extension is omitted in a message (e.g., EncryptedExtensions message) that a server transmits during a TLS handshake or a client device transmits during a TLS handshake. The device can reject early data requests to reduce or eliminate the possibility of replay attacks. For example, a policy author (e.g., application layer policy) can identify one or more resources (e.g., application, URLs, methods) in one or more applications or provided by one or more application servers that are replay-safe and write a policy to allow early data processing just for those resources. The policy author (e.g., application layer policy) can identify one or more resources (e.g., application, URLs, methods) in one or more applications or provided by one or more application servers that are not replay-safe and write a policy to reject early data processing just for those resources. In some embodiments, policy authors (or application operators, administrators) can generate or customize a default policy rule that indicates whether early data processing is to be allowed or disallowed in the event that no other policy rule applies to the current request. 
     Referring to  FIG. 5 , depicted is a block diagram of a system  500  for applying an application layer policy to a transport layer security request. As depicted in  FIG. 5 , a plurality of client devices  502   a - 502   n  can transmit TLS requests  510  to a device  520  that is intermediary to the client device  502   a - 502   n  and a plurality of servers  530   a - 530   n . The TLS requests  510  can include application layer requests  512  for at least one resource  532  provided by at least one server  530 . The device  520  can apply application layer policies  526  to the TLS requests  510  to determine whether to accept or reject an application layer requests  512  included with the TLS request  510 . The device  520  can use the application layer policies  526  to prevent and reject replay attacks for the resources  532   a - 532   n  provided by the servers  530   a - 530   n.    
     The client devices  502   a - 502   n  can be an instance of any client device described herein. For example, the client devices  502   a - 502   n  can be the same as or substantially similar to at least one of clients  102 ( 1 )- 102   n  of  FIG. 1A  or client  102  of  FIG. 1B . The client devices  502   a - 502   n  can include client applications  504   a - 504   n  executing thereon. The client applications  504   a - 504   n  can include or provide browsers  506   a - 506   n  for the client devices  502   a - 502   n  to interact with resources  532   a - 532   n  hosted by the servers  530   a - 530   n . The client applications  504   a - 504   n  may be any instance of any client application or appliance described herein. The client applications  504   a - 504   n  can include or be provided a device (e.g., intermediary device) or appliance. For example, the client applications  504   a - 504   n  can be the same as, substantially similar to, or be provided by appliances  200 ( 1 )- 200 ( n ) of  FIG. 1A  and appliance  200  of  FIGS. 1B-2 . The client applications  504   a - 504   n  with browsers  506   a - 506   n  (e.g., embedded browser (CEB)) can include a CEB. The browsers  506   a - 506   n  can include elements and functionalities of a web browser application or engine. The browsers  506   a - 506   n  can locally render one or more of resources  532   a - 532   n  as a component or extension of the client applications  504   a - 504   n . For example, the browsers  506   a - 506   n  can render a SaaS/Web application inside the CEB which can provide the CEB with full visibility and control of at least one application session. 
     The device  520  can include an intermediary device that are disposed within a network  104  intermediary to the plurality of client devices  502   a - 502   n  and the plurality of servers  530   a - 530   n . The device  520  can include servers, third party servers, proxy servers, HTTP proxy servers, or transport layer security (TLS) servers. The device  520  can be the same as or substantially similar to servers  106 ( 1 )- 106   n  of  FIG. 1A  and server  106  of  FIG. 1B . For example, the device  520  may include an application delivery system for delivering a computing environment, application, and/or data files to client devices  502   a - 502   n . In some embodiments, the device  520  can correspond to a proxy server and include a TLS server  522  and a policy engine  524 . The TLS server  522  can correspond to a server or TLS proxy. The TLS server  522  can provide or implement TLS protocol for communications security over network  104  (e.g., network  104  of  FIG. 1A ) between the plurality of clients  502   a - 502   n  and the plurality of servers  530   a - 530   n.    
     The policy engine  524  can include or correspond to an HTTP policy engine. The policy engine  524  can include one or more application layer policies  526 . For example, the policy engine  524  can include one or more application layer policies  526  for the resources  532   a - 532   n  provided by the servers  530   a - 530   n . In some embodiment, the application layer policies  526  can indicate whether to allow or reject early data processing for one or more of the resources  532   a - 532   n  provided by the servers  530   a - 530   n . For example, the application layer policies  526  can indicate that one or more of the resources  532   a - 532   n  are replay-safe and the application layer policies  526  allow early data processing for respective one or more of the resources  532   a - 532   n  provided by the servers  530   a - 530   n . The application layer policies  526  can indicate that one or more of the resources  532   a - 532   n  are not replay-safe and the application layer policies  526  can reject or disallow early data processing for respective one or more of the resources  532   a - 532   n  provided by the servers  530   a - 530   n.    
     In some embodiments, the application layer policies  526  can include default instructions to allow early data processing for one or more of the resources  532   a - 532   n  provided by the servers  530   a - 530   n  in the event that no other policy rule applies to respective one or more of the resources  532   a - 532   n . The application layer policies  526  can include default instructions to reject or disallow early data processing for one or more of the resources  532   a - 532   n  provided by the servers  530   a - 530   n  in the event that no other policy rule applies to respective one or more of the resources  532   a - 532   n . The application layer policies  526  can identify at least one resource  532 , at least one server  530  or subset of servers  530   a - 530   n  of the plurality of servers  530   a - 530   n . The application layer policies  526  can include a pattern corresponding to a resource  532 . For example, the pattern can include an identifier, string, a URL, or a portion of URL corresponding to a resource  532 . Thus, the policy engine  524  may control and manage the access to, and execution and delivery of, applications or resources  532   a - 532   n  provided by servers  530   a - 530   n . For example, the TLS server  522  can use the policy engine  524  to determine whether a client device  502  may access a resource  532  and/or how the resource  532  should be delivered to the respective client device  502 , such as a server-based computing, streaming or delivering the application locally to the respective client device  502  for local execution. 
     In embodiments, the device  520  can establish TLS connections  514   a - 514   n  with the client devices  502   a - 502   n . The device  520  can establish application connections  540   a - 540   n  between at least one of the client devices  502   a - 502   n  and at least one of the servers  530   a - 530   n . The connections  514   a - 514   n ,  540   a - 540   n  can include any type or form of a session as described herein. For example, connections  514   a - 514   n ,  540   a - 540   n  may include, but not limited to, an application session, an execution session, a desktop session, a hosted desktop session, a terminal services session, a browser session, a remote desktop session, a URL session and a remote application session. The connections  514   a - 514   n ,  540   a - 540   n  (e.g., TLS connections, application connections, application sessions) can include encrypted connections or secure connections established between a client device and a device and/or application server. For example, the connections  514   a - 514   n ,  540   a - 540   n  can include encrypted and/or secure sessions established between a resource  532  and a client device  502  and/or between device  520  and a client device  502 . The connections  514   a - 514   n ,  540   a - 540   n  can include encrypted data or traffic transmitted between at least one resource  532  and a client device  502  and/or the device  520  and a client device  502 . 
     The TLS requests  510  can include a TLS connection request and an application layer request  512 . In some embodiments, the TLS requests  510  can include a first request to establish a TLS connection  514  with device  520  to a client device  502 . The TLS requests  510  can include a second request or application layer request  512  to establish an application connection  540  to at least one server  530  of the plurality of servers  530   a - 530   n  to a client device  502 . The TLS requests  510  can identify the device  520  to establish a TLS connection  514  with the client device  502 . The TLS requests  510  can identify at least one server  530  of the plurality of servers  530   a - 530   n  to establish an application connection  540  with the client device  502 . In some embodiments, the TLS requests  510  can identify at least one resource  532  hosted or provided by at least one server  530  of the plurality of servers  530   a - 530   n . The application layer request  512  can identify at least one server  530  of the plurality of servers  530   a - 530   n  to establish an application connection  540  with the client device  502 . In some embodiments, the application layer request  512  can identify at least one resource  532  hosted or provided by at least one server  530  of the plurality of servers  530   a - 530   n . For example, the application layer request  512  can include a HTTP request. The application layer request  512  can include a pattern corresponding to a resource  532  provided by at least one server  530  of the plurality of servers  530   a - 530   n . In some embodiments, the application layer request  512  can include an identifier, string, a URL, or a portion of URL corresponding to a resource  532  provided by at least one server  530  of the plurality of servers  530   a - 530   n.    
     The servers  530   a - 530   n  can be the same as or substantially similar to servers  106 ( 1 )- 106   n  of  FIG. 1A  and server  106  of  FIG. 1B . For example, the servers  530   a - 530   n  may include an application delivery system for delivering a computing environment, resources  532   a - 532   n , and/or data files to client devices  502   a - 502   n . The servers  530   a - 530   n  can include remote severs or third party servers that host one or more resources  532   a - 532   n . The servers  530   a - 530   n  can include HTTP servers or application servers. The resources  532   a - 532   n  may include resources provided by or hosted by the servers  530   a - 530   n . For example, the resources  532   a - 532   n  may include network applications that are served from and/or hosted on the servers  530   a - 530   n . The resources  532   a - 532   n  can include an application hosted on at least one server  530  accessed by at least one client device  502  via a network  104 . The resources  532   a - 532   n  can include, but not limited to, a web application, a desktop application, remote-hosted application, a virtual application, a software as a service (SaaS) application, a mobile application, an HDX application, a local application, a native application (e.g., native to the client device), and/or a device couple with one or more of the client devices  502   a - 502   n.    
     Network  104  may be a public network, such as a wide area network (WAN) or the Internet. In some embodiments, network  104  may be a private network such as a local area network (LAN) or a company Intranet. Network  104  may employ one or more types of physical networks and/or network topologies, such as wired and/or wireless networks, and may employ one or more communication transport protocols, such as transmission control protocol (TCP), internet protocol (IP), user datagram protocol (UDP) or other similar protocols. 
     Each of the above-mentioned elements or entities is implemented in hardware, or a combination of hardware and software, in one or more embodiments. Each component of the client applications  504   a - 504   n  may be implemented using hardware or a combination of hardware or software detailed above in connection with  FIGS. 1A-4 . For instance, each of these elements or entities can include any application, program, library, script, task, service, process or any type and form of executable instructions executing on hardware of a client device (e.g., the client device  502 ). The hardware includes circuitry such as one or more processors in one or more embodiments. 
     Referring now to  FIGS. 6A-6B , depicted is a flow diagram of one embodiment of a method  600  for applying an application layer policy to a transport layer security request. The functionalities of the method  600  may be implemented using, or performed by, the components detailed herein in connection with  FIGS. 1-5 . In brief overview, a request can be received ( 605 ). A protocol can be determined ( 610 ). A key corresponding to the client can be validated ( 615 ). The request can be decrypted ( 620 ). A policy can be applied to the request ( 625 ). A determination can be made to accept or reject the request ( 630 ). If the request is accepted, a response can be generated to indicate to the client the request was accepted ( 635 ). A portion of the request can be transmitted to a server ( 640 ). If the request is rejected, a response can be generated to indicate to the client the request was rejected ( 645 ). The request can be rejected ( 650 ). 
     Referring now to operation ( 605 ), and in some embodiments, a request  510  can be received. For example, method  600  can include receiving, by a device  520  intermediary to one or more clients  502  and one or more servers  530 , a transport layer security (TLS) request  510  to establish a TLS connection  514  between a client device  502  of the one or more clients  502  and a server  530  of the one or more servers  530 . The TLS request  510  can include an application layer request  512  to a resource  532  of the server  530 . In some embodiments, the TLS request  510  can identify one or more servers  530  of the plurality of servers  530   a - 530   n  to establish an application connection  540  with a client device  502 . The TLS request  510  can identify a resource  532  hosted or provided by at least one server  530  of the plurality of servers  530   a - 530   n.    
     The application layer request  512  can include a HyperText Transfer Protocol (HTTP) request. For example, the application layer request  512  can identify at least one server  530  (e.g., HTTP server) of the plurality of servers  530   a - 530   n  to establish an application connection  540 . In some embodiments, the application layer request  512  can identify at least one resource  532  hosted or provided by at least one server  530  of the plurality of servers  530   a - 530   n . The application layer request  512  can include a pattern for matching against at least a portion of an application layer policy  526 . For example, the application layer request  512  can include a pattern corresponding to a resource  532  provided by at least one server  530  of the plurality of servers  530   a - 530   n . In some embodiments, the application layer request  512  can include an identifier, string, a URL, or a portion of URL corresponding to a resource  532  provided by at least one server  530  of the plurality of servers  530   a - 530   n . The client device  502  can transmit a TLS request  510  to the device  520 . The client device  502  can transmit a plurality of TLS requests  510  to the device  520 . In some embodiments, a plurality of client devices  502   a - 502   n  can transmit a TLS request  510  to the device  520 . A plurality of client devices  502   a - 502   n  can transmit a plurality of TLS requests  510  to the device  520 . 
     The device  520  can be positioned within a network  104  intermediary to the plurality of clients  502   a - 502   n  and a plurality of servers  530   a - 530   n . For example, the device  520  can include intermediary devices disposed between one or more clients  502   a - 502   n  and one or more servers  530   a - 530   n , such as but not limited to, HTTP servers. The device  520  can include servers, third party servers or TLS servers  522 . The device  520  can include a TLS server  522  and a policy engine  526 . The TLS server  522  can implement TLS protocol to provide communications security over a network  104 . In some embodiments, the TLS server  522  can implement the TLS protocol to provide communications security over a network  104 . The device  520  can establish an application connection  540  between a client device  502  and a server  530 . The device  520  can establish a TLS connection  514  between a client device  502  and the device  520 . In some embodiments, the device can establish a plurality TLS connections  514   a - 514   n  to one or more client devices  502   a - 502   n  responsive to a plurality of TLS requests  510 . For example, a TLS connection  514  can be established responsive to each TLS request  510 . In some embodiments, the device  520  can selectively establish TLS connections  514   a - 514   n  responsive to TLS requests  510  based in part application layer policies  526 . The TLS connections  514   a - 514   n  can be established between the client devices  502   a - 502   n  and the device  520 . 
     Referring now to operation ( 610 ), and in some embodiments, a protocol can be determined. In some embodiments, the device  520  and a client device  502  transmitting a TLS request  510  can negotiate an application protocol to use for the TLS request  510 . The application protocol can include, but not limited to HTTP protocol. For example, the device  520  and client device  502  can negotiate using application layer protocol negotiation to determine a protocol for the TLS request  510 . The device  220  can negotiate or determine an application protocol through application layer protocol TLS extension. The application layer negotiation can be performed over a secure connection between the device  520  and the client device  502 . In some embodiments, the application layer negotiation can be performed independent of the application layer protocols. For example, the device  520  and client device  502  can use out-of-band negotiation to determine a protocol for the TLS request  510 . The device  520  and client device  502  can use out-of-band data to process the TLS request  510 . The device  520  can determine to use HTTP protocol responsive to the negotiation. 
     Referring now to operation ( 615 ), and in some embodiments, a key corresponding to the client device  502  can be validated. For example, the TLS request  510  can include a key or verification tool. In some embodiments, the client device  502  can pre-share a key with the device  520  or TLS server  522  prior to transmitting the TLS request  510 . The key can include a verification tool or unique identifier corresponding to the client device  502 . The device  520  or TLS server  522  can receive or accept the key and validate the client device  502  using the key. In some embodiments, the key can include encryption or decryption data. For example, the device  520  or TLS server  522  can use the key to decrypt early application data received from the client device  502 . In some embodiments, the client device  502  can include an early data extension value, early data extension indication, or early data extension identifier in application layer request  512 . In some embodiments, when a pre-shared key is used and early data is allowed for the pre-shared key, the client device  502  can transmit the TLS request  510  and/or application layer request  512  having both the early data extension and the pre-shared key extension. The device  520  can search the TLS request  510  or respective application layer request  512  to determine if an extension for early data is included in the TLS request  510  or application layer request  512  transmitted during the TLS handshake with the client device  502 . The extension for early data can be included in an encrypted extension message included with the TLS request  510  or application layer request  512 . 
     Referring now to operation ( 620 ), and in some embodiments, the request  510 ,  512  can be decrypted. For example, the device  520  can decrypt the TLS request  510 , the application layer request  512 , or both the TLS request  510  and the application layer request  512 . In some embodiments, the TLS request  510  and/or application layer request  512  received at the device  520  can be encrypted. The device  520  can receive the encrypted TLS request  510  and decrypt the encrypted TLS request  510 . The decrypted TLS request  510  can be analyzed within the device  520 . In some embodiments, the decrypted TLS request  510  can be analyzed by the TLS server  522  using the policy engine  524 . The device  520  can receive the encrypted application layer request  512  and decrypt the application layer request  512 . The decrypted application layer request  512  can be analyzed within the device  520 . In some embodiments, the decrypted application layer request  512  can be analyzed by the TLS server  522  using the policy engine  524 . In some embodiments, if the negotiated application protocol is HTTP, the decrypted HTTP application layer request  512  can be analyzed within the device  520  and compared against the configured early data acceptance policy (e.g., application layer policies  526 ). 
     Referring now to operation ( 625 ), and in some embodiments, a policy  526  can be applied to the request  510 . The application layer policies  526  can be stored by the policy engine  524  (e.g., HTTP policy engine). The application layer policies  526  can include, but not limited to, early data acceptance policies. The application layer policies  526  can include, but not limited to, HTTP policies. The application layer policies  526  can be generated by one or more of the servers  530   a - 530   n . For example, the servers  530   a - 530   n  can generate application layer policies  526  to control access to one or more resources  532   a - 532   n  hosted or provided by the respective server  530 . The application layer policies  526  can be generated by administrators of servers  530   a - 530   n . In some embodiments, the device  520  or TLS server  522  can generate application layer policies  526  to control access to one or more resources  532   a - 532   n  hosted or provided by the respective server  530 . The application layer policies  526  can be generated by administrators of the device  520  or TLS server  522 . The application layer policies  526  can allow to disallow early data requests for the one or more resources  532   a - 532   n  hosted or provided by the respective server  530 . The application layer policies  526  may indicate that the one or more resources  532   a - 532   n  hosted or provided by the respective server  530  are replay-safe. The application layer policies  526  may indicate that the one or more resources  532   a - 532   n  hosted or provided by the respective server  530  are not replay-safe. 
     The application layer policies  526  can be generated for accessing resources  532   a - 532   n  of a particulate server  530  and/or for a particular resource  532 . The application layer policies  526  can specify a pattern for matching against at least a portion of a TLS request  510  and/or application layer request  512 . The application layer policies  526  can include a pattern for matching against at least a portion of a TLS request  510  and/or application layer request  512 . For example, the application layer policies  526  can include a pattern corresponding to a resource  532  provided by at least one server  530  of the plurality of servers  530   a - 530   n . In some embodiments, the application layer polices  526  can include an identifier, string, a URL, or a portion of URL corresponding to a resource  532  provided by at least one server  530  of the plurality of servers  530   a - 530   n.    
     The device  520  or TLS server  522  can apply one or more of the application layer policies  526  to the TLS request  510 , to the application layer request  512 , or to both the TLS request  510  and the application layer request  512 . The application layer polies  526  can be used by the device  520  to control access to the resources  532   a - 532   n  provided by the servers  530   a - 530   n . In some embodiments, the device  520  can identify an application layer policy  526  based at least in part on the TLS request  510 , the application layer request  512 , or both the TLS request  510  and the application layer request  512 . The application layer policy  526  can correspond to a policy for accessing one or more resources  532   a - 532   n  provided by the servers  530   a - 530   n . For example, the application layer policies  526  can indicate if a particular resource  532  is replay-safe and, if so, the corresponding application layer policy  526  can include instructions or a policy to allow early data processing for the respective resource  532 . The application layer policies  526  can indicate if a particular resource  532  is not replay-safe and, if so, the corresponding application layer policy  526  can include instructions or a policy to prevent or otherwise disallow early data processing for the respective resource  532 . 
     The application layer policies  526  can be generated having default instructions for resources  532   a - 532   n  in which no early data processing polices have been written or generated. For example, the application layer policies  526  can include a default policy rule that indicates whether early data processing is to be allowed or disallowed in the event that no other policy rule applies to the current request. In some embodiments, the application layer policies  526  can include a default policy rule that indicates that early data processing is to be allowed in the event that no other policy rule applies to a TLS request  510 , application layer request  512 , or requested resource  532 . For example, the application layer policy  526  or the policy engine  524  can include a default policy indicating that early data requests are allowed by default. The application layer policy  526  or the policy engine  524  can include black-list including exemptions to the default policy that includes or enumerates specific resources  532 - 532   n  which are not allowed in early data requests. In some embodiments, the application layer policies  526  can include a default policy rule that indicates that early data processing is to be prevented or disallowed in the event that no other policy rule applies to a TLS request  510 , application layer request  512 , or requested resource  532 . For example, the application layer policy  526  or the policy engine  524  can include a default policy indicating that early data requests are not allowed by default. The application layer policy  526  or the policy engine  524  can include white-list including exemptions to the default policy that includes or enumerates specific resources  532 - 532   n  which are allowed in early data requests. 
     Referring now to operation ( 630 ), and in some embodiments, a determination can be made to accept or reject the request  510 ,  512 . In some embodiments, the device  520 , responsive to applying the application layer policy  526  to the application layer request  512  of the TLS request  510 , can determine whether to accept or reject at least the application layer request  512  of the TLS request  510 . The device  520  can compare a pattern included in the application layer policy  526  to a pattern included in the TLS request  510 , application layer request  512 , or a pattern included in both the TLS request  510 , application layer request  512 . In some embodiments, if the pattern included in the TLS request  510 , application layer request  512 , or both the TLS request  510 , application layer request  512 , the device  520  can determine to accept or reject the request  510 ,  512  based in part on the instructions in the corresponding application layer policy  526 . 
     Referring now to operation ( 635 ), and in some embodiments, if the request  510 ,  512  is accepted, a response can be generated to indicate to the client device  502  the request  510 ,  512  was accepted. The device  520  can determine to accept the TLS request  510 , the application layer request  512 , or both the TLS request  510 , the application layer request  512 . The device  520  can determine accept the TLS request  510 , application layer request  512 , or both the TLS request  510  and the application layer request  512  using the TLS layer or in the TLS layer. In some embodiments, the device  520  can include an extension for early data during a TLS handshake with the client device  502  to indicate allowing both the TLS request  510  and the application layer request  512 . For example, if the application layer policy  526  evaluation results in an allow early data decision, the device  520  can indicate to the client device  502  (e.g., via the EncryptedExtensions message in the TLS handshake) that both the TLS request  510  and the application layer request  512  are accepted. In some embodiments, the device  520  can generate an early data extension in an encrypted extension message (e.g., “early_data” extension in EncryptedExtensions) indicating to the client device  502  if the device  520  intends to allow (e.g., process) the TLS request  510  and application layer request  512  for early data. In some embodiments, the device  520  can establish a TLS connection  514  with the client device  502  responsive to accepting the TLS request  510 . The TLS connection  514  can include an encrypted connection between the device  520  and the client device  502 . 
     Referring now to operation ( 640 ), and in some embodiments, a portion of the request can be transmitted to a server. The device  520  can transmit the application layer request  512  to a server  530  of the plurality of servers  530   a - 530   n  indicated in the respective application layer request  512 . In some embodiments, the device  520  can transmit or forward the HTTP request  512  to server  530  (e.g., HTTP server) of the plurality of servers  530   a - 530   n  indicated in the respective application layer request  512 . The device  520  or the TLS server  522  can proxy an application connection  540  between the client device  502  and the server  530 . For example, the device  520  can establish an application connection  540  with the server  530  of the plurality of servers  530   a - 530   n  indicated in the respective application layer request  512 . The device  520  can establish an application connection  540  with the client device  502  that transmitted the application layer request  512 . In some embodiments, the device  520  can establish the application connection  520  between the client device  502  that transmitted the application layer request  512  and the server  530  indicated in the respective application layer request  512 . In some embodiments, the application connection  540  (e.g., communication channel) between the device  520  (or TLS server  522 ) and the server  532  (e.g., HTTP (application) server) can include or be formed as an encrypted channel. For example, the client device  502  may reside in the proxy or device  520  and forward application layer requests  512  (e.g., HTTP request) to a separate TLS server  522  disposed at or inside the server  530  (e.g., HTTP (application) server). In some embodiments, the device  520  can terminate at the device  520  the TLS connection  514  with the client device  502 . For example, the device  520  can terminate at the device  520  the TLS connection  514  between the client device  502  and the device  520  and establish a communication channel or session between the device  520  and the server  530 . In some embodiments, the communication channel or session between the device  520  and the server  530  may not include TLS protocol or a TLS communication channel. 
     Referring now to operation ( 645 ), and in some embodiments, if the request  510 ,  512  is rejected, a response can be generated to indicate to the client device  502  the request  510 ,  512  was rejected. The device  520  can reject the TLS request  510 , the application layer request  512 , or both the TLS request  510  and the application layer request  512 . The device  520  can determine to reject the TLS request  510 , application layer request  512 , or both the TLS request  510  and the application layer request  512  using the TLS layer or in the TLS layer. For example, the device  520  can omit an extension for early data during the TLS handshake with the client device  502  to indicate acceptance of the TLS request  510  and rejection of the application layer request  512 . For example, the application layer policy  526  evaluation results in a rejection or disallow early data decision, the device  520  can indicate to the client device  502  that the TLS request  510  is accepted and that the application layer request  512  is rejected. The device  520  can discard the decrypted application layer request  512 . In some embodiments, the device  520  can carry out the TLS handshake, omitting the early data extension in an encrypted extension message (e.g., “early_data” extension in EncryptedExtensions) indicating to the client device  502  that the device  520  intends to reject the request for early data. 
     Referring now to operation ( 650 ), and in some embodiments, the request  510 ,  512  can be rejected. The device  520  can reject the TLS request  510 , the application layer request  512 , or both the TLS request  510  and the application layer request  512 . In some embodiments, the device  520  can accept the TLS request  510  and reject the application layer request  512 . For example, the device  520  can establish a TLS connection  514  between the client device  502  and the device  520  and reject the application layer request  512 . The TLS connection  514  can include an encrypted connection between the device  520  and the client device  502 . 
     Various elements, which are described herein in the context of one or more embodiments, may be provided separately or in any suitable subcombination. For example, the processes described herein may be implemented in hardware, software, or a combination thereof. Further, the processes described herein are not limited to the specific embodiments described. For example, the processes described herein are not limited to the specific processing order described herein and, rather, process blocks may be re-ordered, combined, removed, or performed in parallel or in serial, as necessary, to achieve the results set forth herein. 
     It will be further understood that various changes in the details, materials, and arrangements of the parts that have been described and illustrated herein may be made by those skilled in the art without departing from the scope of the following claims.