Patent Publication Number: US-11038863-B2

Title: Facilitating encrypted persistent storage in browsers

Description:
INCORPORATION BY REFERENCE 
     An Application Data Sheet is filed concurrently with this specification as part of the present application. Each application that the present application claims benefit of or priority to as identified in the concurrently filed Application Data Sheet is incorporated by reference herein in its entirety and for all purposes. 
     COPYRIGHT NOTICE 
     A portion of the disclosure of this patent document contains material which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure as it appears in the United States Patent and Trademark Office patent file or records but otherwise reserves all copyright rights whatsoever. 
     TECHNICAL FIELD 
     This patent document generally relates to facilitating encrypted persistent storage in browsers. More specifically, this patent document discloses techniques for facilitating the persistent storage of data in a secure manner across browser sessions and the use of cryptographic keys across browser sessions to decrypt encrypted session data. 
     BACKGROUND 
     In a web application environment, customer data is typically stored in a data center. Since security of the customer data is often paramount to many customer situations, the customer data cannot be stored outside the data center. As a result, a browser operating on a client device typically requests customer data from a web server each time customer data is displayed. This leads to inefficiencies because the client device must make multiple data requests to the server in order to retrieve data across browser tabs and page refreshes. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The included drawings are for illustrative purposes and serve only to provide examples of possible structures and operations for the disclosed inventive systems, apparatus, methods and computer program products. These drawings in no way limit any changes in form and detail that may be made by one skilled in the art without departing from the spirit and scope of the disclosed implementations. 
         FIG. 1  shows an example of a web application environment  100 , in accordance with some implementations. 
         FIG. 2  shows an example of an aspect of a cross-session secure storage system  200 , in accordance with some implementations. 
         FIG. 3  shows a flowchart of an example of a method  300  for implementing persistent encrypted storage in browsers, in accordance with some implementations. 
         FIG. 4  shows a process flow diagram of an example of a method  400  for implementing persistent encrypted storage during a browser session, in accordance with some implementations. 
         FIG. 5  shows a process flow diagram of an example of a method  500  for implementing persistent encrypted storage across browser sessions, in accordance with some implementations. 
         FIG. 6  shows a process flow diagram of an example of a method  600  for implementing cryptographic keys across browser sessions, in accordance with some implementations. 
         FIG. 7  shows a flowchart of an example of a method  700  for implementing persistent encrypted storage using a cryptographic key, in accordance with some implementations. 
         FIG. 8  shows an example of a system  800 , in accordance with some implementations. 
         FIG. 9A  shows a block diagram of an example of an environment  10  in which an on-demand database service can be used in accordance with some implementations. 
         FIG. 9B  shows a block diagram of an example of some implementations of elements of  FIG. 9A  and various possible interconnections between these elements. 
         FIG. 10A  shows a system diagram of an example of architectural components of an on-demand database service environment  900 , in accordance with some implementations. 
         FIG. 10B  shows a system diagram further illustrating an example of architectural components of an on-demand database service environment, in accordance with some implementations. 
     
    
    
     DETAILED DESCRIPTION 
     Examples of systems, apparatus, methods and computer program products according to the disclosed implementations are described in this section. These examples are being provided solely to add context and aid in the understanding of the disclosed implementations. It will thus be apparent to one skilled in the art that implementations may be practiced without some or all of these specific details. In other instances, certain operations have not been described in detail to avoid unnecessarily obscuring implementations. Other applications are possible, such that the following examples should not be taken as definitive or limiting either in scope or setting. 
     In the following detailed description, references are made to the accompanying drawings, which form a part of the description and in which are shown, by way of illustration, specific implementations. Although these implementations are described in sufficient detail to enable one skilled in the art to practice the disclosed implementations, it is understood that these examples are not limiting, such that other implementations may be used and changes may be made without departing from their spirit and scope. For example, the operations of methods shown and described herein are not necessarily performed in the order indicated. It should also be understood that the methods may include more or fewer operations than are indicated. In some implementations, operations described herein as separate operations may be combined. Conversely, what may be described herein as a single operation may be implemented in multiple operations. 
     Typically, web applications do not enable data maintained in data centers to be persisted locally at client devices. Furthermore, browsers generally do not support encrypted data storage. As a result, when multiple instances of a web application are simultaneously active on a given client device, the client device must typically re-fetch data from a web server for each instance of the web application. These inefficiencies can impact the operation of the web server, as well as the client device. 
     Various implementations described or referenced herein are directed to different methods, apparatus, systems, and computer program products for facilitating the persistent storage of data in a secure manner across browser sessions (e.g., page refreshes and browser tabs) of a web browser. The system may use a database such as an indexed database to provide structured persistent storage. In addition, the system may employ web cryptography in the browser to encrypt session data and decrypt encrypted session data stored in the structured persistent storage. The system may utilize cryptographic logic to generate cryptographic session-based keys and utilize storage service abstractions of how and where to store data. The cryptographic session keys may be stored in ephemeral memory to ensure that encrypted data is stored in a secure manner. 
     The system may encrypt cached data at rest and persist it to disk. In accordance with various implementations, the browser stores encrypted session data in a browser cache. In some implementations, the system may use an indexed database to store encrypted session data. Encrypted session data stored in the indexed database may be accessed via an application programming interface (API). 
     Session data may include data such as customer data. For example, the data may be obtained from fields of records stored in a customer database. As another example, the data may include metadata such as information indicating locations at which the data is stored, either locally or remotely. 
     In accordance with various implementations, the system may derive cryptographic keys from session identifiers. When a web application is booted, the web application may execute a per-session request for a cryptographic key that is derived from the user&#39;s session and which is linked to the lifecycle of the session data. In a typical use scenario, there is one main authentication session and different, subsequent browser sub-sessions derived from that main authentication session. The system may include an abstraction logic layer to access browser cryptography logic and encrypted session data across browser tabs and page refreshes. In addition, the system may implement key storage logic to accelerate performance during browser sessions of a web browser, resulting in fewer server requests. 
     By way of illustration, John is an employee at an organization, Pyramid Construction, Inc. John logs in to a web site of the organization to access a web application that provides information regarding business opportunities of the organization. John accesses a user interface (UI) using a browser of a client device to view data pertaining to a business opportunity, XYZ. John is viewing the information via a web page rendered via a display when the browser crashes. After the browser crashes, the data will still be accessible, whereas with conventional approaches the data will have been purged and is no longer accessible to the browser. The disclosed techniques may be applied to facilitate the encryption, retrieval, and decryption of session data across browser sessions of a web browser, as will be described in further detail below. 
       FIG. 1  shows an example of a web application environment  100 , in accordance with some implementations. A web application environment  100  generally includes a client device  102  (e.g., mobile phone, laptop, tablet, and personal computer), a browser  104  (e.g., Safari, Internet Explorer, Google Chrome, Mozilla Firefox, Opera), and a server  106  (e.g., LAMP, Windows server, etc.). To improve the performance of web applications it is advantageous to store customer data locally at the client device  102 . However, this has historically not been feasible, since there fails to be a mechanism for securely persisting customer data outside of the data center. This leads to inefficiencies because the client device  102  must make multiple data requests to the server  106  in order to retrieve data across browser tabs and page refreshes. 
     In one typical use scenario, a user completes a user authentication process to use the web application and receives a session ID. The client device  102  may transmit a request for a cryptographic key, and a cryptographic key may be generated for use in encrypting session data received during browser sessions associated with the session ID. Encrypted session data may be stored to disk or ephemeral memory, depending on the browser capabilities. 
     If the browser closes or crashes during the session and is subsequently re-activated, the user may be automatically “re-authenticated.” In some implementations, the re-authentication process may include determining whether the current browser session is a child of, or related to, the previous browser session. If such a relationship is determined, a new encryption key for the new session may be generated that is compatible with the encrypted data from the previous session. If the new session is not a child of, or related to, the previous session, a cryptographic key that is not compatible with the encrypted data from the previous session may be generated. As a result, the previously stored encrypted session data in the browser cache may become inaccessible, and the session data may be retrieved from the server again. 
     In some implementations, the browser may determine if a cryptographic key is valid by decrypting an encrypted sentinel value. This additional security check enables system administrators a greater degree of access controls over customer data. For example, a system administrator may execute control to disallow access to cached data while browser  104  is offline, rendering the cryptographic key invalid. In addition, a system administrator may further disallow the user to re-authenticate and retrieve the customer data from the server. 
     If the cryptographic key cannot decrypt the encrypted sentinel value, the browser may ascertain that the cryptographic key is not valid. Where the cryptographic key is determined to be invalid, the encrypted session data may become inaccessible and the encrypted session data may be flushed from the browser cache or database. After the session data has become inaccessible, the browser may request the session data from the server again. 
       FIG. 2  shows an example of an aspect of a cross-session secure storage system  200 , in accordance with some implementations. As shown in this example, a cross-session secure storage system  200  includes a browser session  202  between a server  204  operated by an administrator  210  and a browser  206  executed by a client system  216  operated by a user. The browser session  202  may be linked to (e.g., related to) a main authentication session  212  via a common session identifier (ID) provided by server  204  to browser  206 . The browser session  202  may utilize encrypted session data  208  that is encrypted and decrypted using a cryptographic key  220  via an encryption abstraction layer  214 . Although a single browser session  202  of a web browser is illustrated in this example, encrypted session data  208  may also be encrypted and decrypted during another browser session of the web browser using cryptographic key  220  or another backwards compatible cryptographic key. The cross-session secure storage system  200  may be operated in accordance with a process for persistent encrypted storage in browser  206 , as will be described in further detail below with reference to  FIG. 3 . 
       FIG. 3  shows a flowchart of an example of a method  300  for implementing persistent encrypted storage in web browsers, in accordance with some implementations. As shown in this example, a process for persistent encrypted storage in web browsers  300  may assign a session ID from a main authentication session to a browser session and a cryptographic key (e.g., a symmetric or asymmetric cryptographic key) associated with the session ID may be generated at  302 . (The cryptographic key may be applied via an encryption abstraction layer to encrypt session data in memory at  304 . 
     A subsequent browser session may be initiated, either automatically or in response to a user action. For example, a subsequent browser session may be initiated if the browser crashes. As another example, a subsequent browser session may be initiated in response to a page refresh. As yet another example, a subsequent browser session may be initiated in association with a browser tab. 
     During the subsequent browser session, the web browser may transmit a cryptographic key request to a server at  306 . The server may perform a session check to determine if the browser session is a child of the main authentication session at  308 . As described above, the session check may be performed to determine whether the cryptographic key is valid. In some implementations, the session check may include decrypting a dummy encrypted value (e.g., sentinel value) with the cryptographic key. 
     If the session check succeeds, previously encrypted session data may be retrieved from memory and decrypted using the cryptographic key. If the session check fails, the browser may request re-transmission of the session data from the server at  310 . In some implementations, if the session check fails, the main authentication session may invalidate the cryptographic key, and the browser session may restart. Therefore, decryption of the session data in the memory may be dependent upon the session check succeeding. 
       FIG. 4  shows a process flow diagram of an example of a method  400  for implementing persistent encrypted storage during a browser session, in accordance with some implementations. Operations that may be performed between a client  402  and system  404  including a web server are described in further detail below. More particularly, a user of a client device  402  may complete login  406  to system  404 . After the user has successfully completed a login process, system  404  may provide a session identifier (SID) at  408  to client  402 . Client  402  may request a cryptographic key at  410  from system  404 . For example, client  402  may transmit a key request that includes the SID, enabling system  404  to assign a cryptographic key for the session. System  404  may provide a cryptographic key at  412  to client  402 . Client  402  may fetch data at  414  from system  404  during a browser session. After receiving session data at  416  from system  404 , client  402  may encrypt the session data using the cryptographic key at  418  and store the encrypted data in memory at  420 . For example, the encrypted data may be stored in a browser cache or indexed database. The encrypted data may subsequently be retrieved from memory and decrypted using the cryptographic key during the browser session or subsequent related browser sessions. 
     The user may choose to log out, as shown at  422 . After the user has logged out, the system  404  may invalidate the session ID and/or cryptographic key associated with the session at  424 . After the cryptographic key has been invalidated, the key may no longer be used to decrypt previously stored session data. In addition, the encrypted session data may be deleted. For example, the browser cache may be purged of the encrypted session data. 
       FIG. 5  shows a process flow diagram of an example of a method  500  for implementing persistent encrypted storage across browser sessions, in accordance with some implementations. Operations that may be performed by a system  502  including a web server and a client browser during a first browser session  504  and a second browser session  506  are described below. As shown in this example, during a first browser session  504  of a web browser, the client browser may send a cryptographic key request to system  502  at  508 , where the cryptographic key request identifies a SID associated with the first browser session. The client browser may obtain a first cryptographic key associated with the session ID at  510 . For example, the first cryptographic key may be a symmetric or asymmetric cryptographic key. 
     The client browser may fetch data during the first browser session at  512 . After receiving session data at  514 , the client browser may apply the first cryptographic key to generate encrypted session data at  516 . The encrypted session data may be stored in memory at  518 . For example, the encrypted session data may be stored in a memory of a browser (e.g., a browser cache). 
     A second browser session that is related to the first browser session may be initiated. For example, the second browser session may be initiated after a page refresh or after the user clicks on another tab within the web page. During the second browser session, the web browser may transmit a second cryptographic key request to the web server at  520 . Since the second browser session may be associated with the SID of the first browser session, the second key request may include the SID. Responsive to the second cryptographic key request, the web browser may receive a second cryptographic key from the web server at  522 . 
     In some implementations, the second cryptographic key may be backwards compatible with the first cryptographic key. For example, the second cryptographic key may be used to decrypt previously stored encrypted session data. During the second browser session, the web browser may retrieve the encrypted session data from the memory at  524 . The encrypted session data may then be decrypted using the second cryptographic key at  526 . 
     In some instances, a cryptographic key may be backwards compatible, but not forward compatible. In other words, a cryptographic key may be used to decrypt previously stored session data, but it may not be used to decrypt encrypted session data stored during subsequent browser sessions. 
     In some implementations, the browser may determine whether a particular cryptographic key is valid or “functional.” In other words, the browser may determine whether a particular cryptographic key is configured to decrypt encrypted session data. In some implementations, the browser may determine whether a particular cryptographic key is valid (e.g., configured to decrypt encrypted session data) by decrypting an encrypted sentinel value with the cryptographic key. For example, the browser may determine whether the second cryptographic key is valid by decrypting an encrypted sentinel value with the second cryptographic key. If the cryptographic key is determined to be valid, the browser may decrypt previously encrypted session data using the cryptographic key. For example, if the second cryptographic key is determined to be valid, session data that was encrypted during the first browser session may be decrypted using the second cryptographic key. 
       FIG. 6  shows a process flow diagram of an example of a method  600  for implementing cryptographic keys across browser sessions, in accordance with some implementations. As described above with reference to  FIG. 5 , two different browser sessions or instances may use different cryptographic keys across different instances of a web application. In this example, the first cryptographic key associated with the first browser session may be used to decrypt data that has been received and encrypted during the first browser session. Similarly, the second cryptographic key associated with the second browser session may be used to decrypt data that has been received and encrypted during the second browser session. 
     In some implementations, cryptographic keys associated with a particular session ID are backwards compatible, but are not forwards compatible. Thus, the second cryptographic key associated with the session ID may be used to decrypt session data that was encrypted during the first browser session, while the first cryptographic key associated with the session ID may not be used to decrypt session data that is encrypted during the second browser session. 
     In some implementations, all cryptographic keys that are generated in association with a particular SID are identical. However, even where the cryptographic keys that are generated in association a SID are identical, cryptographic keys may periodically be updated or “cycled” over time to increase the security with which session data is encrypted and stored. As a result, two different cryptographic keys associated with the same SID may be different from each other at a given point in time. 
     In accordance with various implementations, a second browser instance operating during the second browser session transmits the second cryptographic key to a first browser instance operating during the first browser session so that the first browser instance may decrypt session data that is encrypted during the second browser session. As shown in this example, the second browser instance may fetch session data at  602 . After receiving session data  2  at  604 , the second browser instance may apply the second cryptographic key to encrypt the session data  2  received during the second browser session at  606 . After storing encrypted session data  2  at  608 , encrypted session data  2  may be retrieved and decrypted using the second cryptographic key. 
     As shown in this example, the second browser instance may transmit a key notification including the second cryptographic key at  610  to the first browser instance, enabling the first browser instance to use the second cryptographic key to decrypt session data that was encrypted during the second browser session. For example, the second browser instance may transmit the key notification in response to obtaining the second cryptographic key. The first browser instance may store the second cryptographic key at  612 . For example, the second cryptographic key may be stored in ephemeral memory. The first browser instance may retrieve encrypted data  2  (encrypted during the second browser session) from memory (e.g., a browser cache) at  614  and decrypt the encrypted data  2  at  616  using the second cryptographic key. In this manner, new or updated cryptographic keys may be communicated across browser instances operating during related browser sessions. 
       FIG. 7  shows a flowchart of an example of a method  700  for implementing persistent encrypted storage using a cryptographic key, in accordance with some implementations. As shown in this example, a web browser may transmit a cryptographic key request to a web server at  702  to request a cryptographic key associated with a particular Session ID. After the web browser receives a cryptographic key associated with the Session ID at  704  from the web server, the web browser may attempt to decrypt previously encrypted session data. However, it is possible that an administrator has disallowed access to cached data by invalidating the cryptographic key. 
     In accordance with various implementations, the browser may periodically determine whether the cryptographic key is valid at  706 . In some implementations, the browser may communicate with the web server to determine whether the cryptographic key is valid. In further implementations, the web browser may determine whether the cryptographic key is valid by determining whether the cryptographic key decrypts a sentinel value within a database. 
     If the web browser determines that the cryptographic key is not valid (e.g., the cryptographic key has not successfully decrypted the sentinel value) at  708 , the web browser may delete the encrypted session data (e.g., by clearing a browser cache) at  710 . The web browser may subsequently request session data from the web server. 
     As described above, a browser instance operating during a browser session may transmit a cryptographic key to other browser instances operating during “related” browser sessions (e.g., other browser sessions associated with the same session ID). In some implementations, if the cryptographic key is determined to be valid, the browser instance may transmit the cryptographic key to other browser instance(s) associated with the session ID at  712 . In addition, the web browser may determine whether session data associated with the session ID is in memory of the client device at  714 . For example, the web browser may check whether session data associated with the session ID is in a browser cache or database of the web browser. If the browser determines at  716  that the session data associated with the session ID is in the memory, the browser may retrieve the encrypted session data from the memory at  718  and decrypt the encrypted session data using the cryptographic key at  720 . If the web browser determines that the session data associated with the session ID is not in memory, the browser may request the session data from a web server at  722 , encrypt the session data using the cryptographic key at  724 , and store the encrypted session data in the memory (e.g., browser cache or database) at  726 . 
       FIG. 8  shows an example of a system  800 , in accordance with some implementations. In various embodiments, system  800  may include one or more physical and/or logical devices that collectively provide the functionalities described herein. In some embodiments, system  800  may comprise one or more replicated and/or distributed physical or logical devices. 
     In some embodiments, system  800  may include one or more computing resources provisioned from a “cloud computing” provider, for example, Amazon Elastic Compute Cloud (“Amazon EC2”), provided by Amazon.com, Inc. of Seattle, Wash.; Sun Cloud Compute Utility, provided by Sun Microsystems, Inc. of Santa Clara, Calif.; Windows Azure, provided by Microsoft Corporation of Redmond, Wash., and the like. In this example, system  800  includes a bus  802  interconnecting several components including a network interface  808 , a display  806 , a central processing unit  810 , and a memory  804 . 
     Memory  804  generally comprises a random access memory (“RAM”) and permanent non-transitory mass storage device, such as a hard disk drive or solid-state drive. Memory  804  may store an operating system  812 . These and other software components may be loaded into memory  804  of system  800  using a drive mechanism (not shown) associated with a non-transitory computer-readable medium  816 , such as a floppy disc, tape, DVD/CD-ROM drive, memory card, or the like. 
     Memory  804  may include a database  814  such as an indexed database. In some embodiments, system  800  may communicate with database  814  via network interface  808 , a storage area network (“SAN”), a high-speed serial bus, and/or via the other suitable communication technology. 
     In some implementations, database  814  may comprise one or more storage resources provisioned from a “cloud storage” provider, for example, Amazon Simple Storage Service (“Amazon S3”), provided by Amazon.com, Inc. of Seattle, Wash., Google Cloud Storage, provided by Google, Inc. of Mountain View, Calif., and the like. 
     In various implementations, system  800  may include a desktop PC, server, workstation, mobile phone, laptop, tablet, set-top box, appliance, or other computing device that is capable of performing operations such as those described herein. In some implementations, system  800  may include many more components than those shown in  FIG. 8 . However, it is not necessary that all of these generally conventional components be shown in order to disclose an illustrative embodiment. 
     Collectively, the various tangible components or a subset of the tangible components may be referred to herein as “logic” configured or adapted in a particular way, for example as logic configured or adapted with particular software or firmware. “Logic” may refer to machine memory circuits, non-transitory machine readable media, and/or circuitry which by way of its material and/or material-energy configuration comprises control and/or procedural signals, and/or settings and values (such as resistance, impedance, capacitance, inductance, current/voltage ratings, etc.), that may be applied to influence the operation of a device. Magnetic media, electronic circuits, electrical and optical memory (both volatile and nonvolatile), and firmware are examples of logic. Logic specifically excludes pure signals or software per se (however does not exclude machine memories comprising software and thereby forming configurations of matter). 
     Those skilled in the art will appreciate that logic may be distributed throughout one or more devices, and/or may be comprised of combinations memory, media, processing circuits and controllers, other circuits, and so on. Therefore, in the interest of clarity and correctness logic may not always be distinctly illustrated in drawings of devices and systems, although it is inherently present therein. The techniques and procedures described herein may be implemented via logic distributed in one or more computing devices. The particular distribution and choice of logic will vary according to implementation. Those having skill in the art will appreciate that there are various logic implementations by which processes and/or systems described herein can be effected (e.g., hardware, software, and/or firmware), and that the preferred vehicle will vary with the context in which the processes are deployed. “Software” refers to logic that may be readily readapted to different purposes (e.g. read/write volatile or nonvolatile memory or media). “Firmware” refers to logic embodied as read-only memories and/or media. “Hardware” refers to logic embodied as analog and/or digital circuits. If an implementer determines that speed and accuracy are paramount, the implementer may opt for a hardware and/or firmware vehicle; alternatively, if flexibility is paramount, the implementer may opt for a solely software implementation; or, yet again alternatively, the implementer may opt for some combination of hardware, software, and/or firmware. Hence, there are several possible vehicles by which the processes described herein may be effected, none of which is inherently superior to the other in that any vehicle to be utilized is a choice dependent upon the context in which the vehicle will be deployed and the specific concerns (e.g., speed, flexibility, or predictability) of the implementer, any of which may vary. Those skilled in the art will recognize that optical aspects of implementations may involve optically-oriented hardware, software, and or firmware. 
     The foregoing detailed description has set forth various embodiments of the devices and/or processes via the use of block diagrams, flowcharts, and/or examples. Insofar as such block diagrams, flowcharts, and/or examples contain one or more functions and/or operations, it will be understood as notorious by those within the art that each function and/or operation within such block diagrams, flowcharts, or examples can be implemented, individually and/or collectively, by a wide range of hardware, software, firmware, or virtually any combination thereof. Several portions of the subject matter described herein may be implemented via Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs), digital signal processors (DSPs), or other integrated formats. However, those skilled in the art will recognize that some aspects of the embodiments disclosed herein, in whole or in part, can be equivalently implemented in standard integrated circuits, as one or more computer programs running on one or more computers (e.g., as one or more programs running on one or more computer systems), as one or more programs running on one or more processors (e.g., as one or more programs running on one or more microprocessors), as firmware, or as virtually any combination thereof, and that designing the circuitry and/or writing the code for the software and/or firmware would be well within the skill of one of skill in the art in light of this disclosure. 
     In addition, those skilled in the art will appreciate that the mechanisms of the subject matter described herein are capable of being distributed as a program product in a variety of forms, and that an illustrative embodiment of the subject matter described herein applies equally regardless of the particular type of signal bearing media used to actually carry out the distribution. Examples of a signal bearing media include, but are not limited to, the following: recordable type media such as floppy disks, hard disk drives, CD ROMs, digital tape, flash drives, SD cards, solid state fixed or removable storage, and computer memory. 
     In a general sense, those skilled in the art will recognize that the various aspects described herein which can be implemented, individually and/or collectively, by a wide range of hardware, software, firmware, or any combination thereof can be viewed as being composed of various types of “circuitry.” Consequently, as used herein “circuitry” includes, but is not limited to, electrical circuitry having at least one discrete electrical circuit, electrical circuitry having at least one integrated circuit, electrical circuitry having at least one application specific integrated circuit, circuitry forming a general purpose computing device configured by a computer program (e.g., a general purpose computer configured by a computer program which at least partially carries out processes and/or devices described herein, or a microprocessor configured by a computer program which at least partially carries out processes and/or devices described herein), circuitry forming a memory device (e.g., forms of random access memory), and/or circuitry forming a communications device (e.g., a modem, communications switch, or optical-electrical equipment). 
     Those skilled in the art will recognize that it is common within the art to describe devices and/or processes in the fashion set forth herein, and thereafter use standard engineering practices to integrate such described devices and/or processes into larger systems. That is, at least a portion of the devices and/or processes described herein can be integrated into a network processing system via a reasonable amount of experimentation. 
     Various implementations described or referenced herein are directed to different methods, apparatus, systems, and computer program products for facilitating the encrypted persistent storage of session data across browser sessions. Some but not all of the techniques described or referenced herein are implemented using or in conjunction with a customer relationship management (CRM) system or other database management system. CRM systems have become a popular way to manage and analyze customer interactions and data throughout the business lifecycle. Salesforce.com, Inc. is a provider of CRM services and other database management services, any of which can be accessed and used in conjunction with the techniques disclosed herein in some implementations. In some but not all implementations, these various services can be provided in a cloud computing environment, for example, in the context of a multi-tenant database system. Thus, the disclosed techniques can be implemented without having to install software locally, that is, on computing devices of users interacting with services available through the cloud. 
     Some CRM systems can be implemented in various settings, including organizations. For instance, a CRM system can be implemented to provide database access to users within an enterprise such as a company or business partnership, or a group of users within such an organization. For instance, employee users in a division of a business organization may share data with users in another division of the business organization. In the example of a multi-tenant database system, each organization or group within the organization can be a respective tenant of the system, as described in greater detail below. In some but not all implementations, the disclosed methods, apparatus, systems, and computer program products may be configured or designed for use in a multi-tenant database environment. 
     The term “multi-tenant database system” generally refers to those systems in which various elements of hardware and/or software of a database system may be shared by one or more customers. For example, a given application server may simultaneously process requests for a great number of customers, and a given database table may store rows of data such as customer sales data for a potentially much greater number of customers. 
     Where there are multiple tenants, a user is typically associated with a particular tenant. For example, a user could be a salesperson of a company, which is a tenant of the database system that provides a database service. 
     In some implementations, data objects in the form of CRM records such as cases, accounts, or opportunities are stored in a database system. Updates to a record may include any change to a record. Examples of record updates include field changes in the record, updates to the status of a record, as well as the creation or deletion of the record itself. 
     The term “record” generally refers to a data entity having fields with values and stored in database system. An example of a record is an instance of a data object created by a user of the database service, for example, in the form of a CRM record about a particular (actual or potential) business relationship or project. The record can have a data structure defined by the database service (a standard object) or defined by a user (custom object). For example, a record can be for a business partner or potential business partner (e.g., a client, vendor, distributor, etc.) of the user, and can include information describing an entire company, subsidiaries, or contacts at the company. As another example, a record can be a project that the user is working on, such as an opportunity (e.g., a possible sale) with an existing partner, or a project that the user is trying to get. 
     In one implementation of a multi-tenant database system, each record for the tenants has a unique identifier stored in a common table. A record has data fields that are defined by the structure of the object (e.g., fields of certain data types and purposes). A record can also have custom fields defined by a user. A field can be another record or include links thereto, thereby providing a parent-child relationship between the records. 
     A record can also have a status, the update of which can be provided by an owner of the record or other users having suitable write access permissions to the record. The owner can be a single user, multiple users, or a group. 
     In various implementations, an event can be an update of a record and/or can be triggered by a specific action by a user. Which actions trigger an event can be configurable. 
     Some non-limiting examples of systems, apparatus, and methods are described below for implementing database systems and enterprise level networking systems in conjunction with the disclosed techniques. Such implementations can provide more efficient use of a database system. Data may be synchronized between a database system of a primary organization and a database system of a secondary organization. Data synchronization may be suspended and resumed, as described above. 
       FIG. 9A  shows a block diagram of an example of an environment  10  in which an on-demand database service exists and can be used in accordance with some implementations. Environment  10  may include user systems  12 , network  14 , database system  16 , processor system  17 , application platform  18 , network interface  20 , tenant data storage  22 , system data storage  24 , program code  26 , and process space  28 . In other implementations, environment  10  may not have all of these components and/or may have other components instead of, or in addition to, those listed above. 
     A user system  12  may be implemented as any computing device(s) or other data processing apparatus such as a machine or system used by a user to access a database system  16 . For example, any of user systems  12  can be a handheld and/or portable computing device such as a mobile phone, a smartphone, a laptop computer, or a tablet. Other examples of a user system include computing devices such as a work station and/or a network of computing devices. As illustrated in  FIG. 9A  (and in more detail in  FIG. 9B ) user systems  12  might interact via a network  14  with an on-demand database service, which is implemented in the example of  FIG. 9A  as database system  16 . 
     An on-demand database service, implemented using system  16  by way of example, is a service that is made available to users who do not need to necessarily be concerned with building and/or maintaining the database system. Instead, the database system may be available for their use when the users need the database system, i.e., on the demand of the users. Some on-demand database services may store information from one or more tenants into tables of a common database image to form a multi-tenant database system (MTS). A database image may include one or more database objects. A relational database management system (RDBMS) or the equivalent may execute storage and retrieval of information against the database object(s). Application platform  18  may be a framework that allows the applications of system  16  to run, such as the hardware and/or software, e.g., the operating system. In some implementations, application platform  18  enables creating, managing and executing one or more applications developed by the provider of the on-demand database service, users accessing the on-demand database service via user systems  12 , or third party application developers accessing the on-demand database service via user systems  12 . 
     The users of user systems  12  may differ in their respective capacities, and the capacity of a particular user system  12  might be entirely determined by permissions (permission levels) for the current user. For example, when a salesperson is using a particular user system  12  to interact with system  16 , the user system has the capacities allotted to that salesperson. However, while an administrator is using that user system to interact with system  16 , that user system has the capacities allotted to that administrator. In systems with a hierarchical role model, users at one permission level may have access to applications, data, and database information accessible by a lower permission level user, but may not have access to certain applications, database information, and data accessible by a user at a higher permission level. Thus, different users will have different capabilities with regard to accessing and modifying application and database information, depending on a user&#39;s security or permission level, also called authorization. 
     Network  14  is any network or combination of networks of devices that communicate with one another. For example, network  14  can be any one or any combination of a LAN (local area network), WAN (wide area network), telephone network, wireless network, point-to-point network, star network, token ring network, hub network, or other appropriate configuration. Network  14  can include a TCP/IP (Transfer Control Protocol and Internet Protocol) network, such as the global internetwork of networks often referred to as the Internet. The Internet will be used in many of the examples herein. However, it should be understood that the networks that the present implementations might use are not so limited. 
     User systems  12  might communicate with system  16  using TCP/IP and, at a higher network level, use other common Internet protocols to communicate, such as HTTP, FTP, AFS, WAP, etc. In an example where HTTP is used, user system  12  might include an HTTP client commonly referred to as a “browser” for sending and receiving HTTP signals to and from an HTTP server at system  16 . Such an HTTP server might be implemented as the sole network interface  20  between system  16  and network  14 , but other techniques might be used as well or instead. In some implementations, the network interface  20  between system  16  and network  14  includes load sharing functionality, such as round-robin HTTP request distributors to balance loads and distribute incoming HTTP requests evenly over a plurality of servers. At least for users accessing system  16 , each of the plurality of servers has access to the MTS&#39; data; however, other alternative configurations may be used instead. 
     In one implementation, system  16 , shown in  FIG. 9A , implements a web-based CRM system. For example, in one implementation, system  16  includes application servers configured to implement and execute CRM software applications as well as provide related data, code, forms, web pages and other information to and from user systems  12  and to store to, and retrieve from, a database system related data, objects, and Webpage content. With a multi-tenant system, data for multiple tenants may be stored in the same physical database object in tenant data storage  22 , however, tenant data typically is arranged in the storage medium(s) of tenant data storage  22  so that data of one tenant is kept logically separate from that of other tenants so that one tenant does not have access to another tenant&#39;s data, unless such data is expressly shared. In certain implementations, system  16  implements applications other than, or in addition to, a CRM application. For example, system  16  may provide tenant access to multiple hosted (standard and custom) applications, including a CRM application. User (or third party developer) applications, which may or may not include CRM, may be supported by the application platform  18 , which manages creation of applications, storage of the applications into one or more database objects and executing of the applications in a virtual machine in the process space of the system  16 . 
     One arrangement for elements of system  16  is shown in  FIGS. 9A and 9B , including a network interface  20 , application platform  18 , tenant data storage  22  for tenant data  23 , system data storage  24  for system data  25  accessible to system  16  and possibly multiple tenants, program code  26  for implementing various functions of system  16 , and a process space  28  for executing MTS system processes and tenant-specific processes, such as running applications as part of an application hosting service. Additional processes that may execute on system  16  include database indexing processes. 
     Several elements in the system shown in  FIG. 9A  include conventional, well-known elements that are explained only briefly here. For example, each user system  12  could include a desktop personal computer, workstation, laptop, PDA, cell phone, or any wireless access protocol (WAP) enabled device or any other computing device capable of interfacing directly or indirectly to the Internet or other network connection. The term “computing device” is also referred to herein simply as a “computer.” User system  12  typically runs an HTTP client, e.g., a browsing program, such as Microsoft&#39;s Internet Explorer browser, Netscape&#39;s Navigator browser, Opera&#39;s browser, or a WAP-enabled browser in the case of a cell phone, PDA or other wireless device, or the like, allowing a user (e.g., subscriber of the multi-tenant database system) of user system  12  to access, process and view information, pages and applications available to it from system  16  over network  14 . Each user system  12  also typically includes one or more user input devices, such as a keyboard, a mouse, trackball, touch pad, touch screen, pen or the like, for interacting with a GUI provided by the browser on a display (e.g., a monitor screen, LCD display, OLED display, etc.) of the computing device in conjunction with pages, forms, applications and other information provided by system  16  or other systems or servers. Thus, “display device” as used herein can refer to a display of a computer system such as a monitor or touch-screen display, and can refer to any computing device having display capabilities such as a desktop computer, laptop, tablet, smartphone, a television set-top box, or wearable device such Google Glass® or other human body-mounted display apparatus. For example, the display device can be used to access data and applications hosted by system  16 , and to perform searches on stored data, and otherwise allow a user to interact with various GUI pages that may be presented to a user. As discussed above, implementations are suitable for use with the Internet, although other networks can be used instead of or in addition to the Internet, such as an intranet, an extranet, a virtual private network (VPN), a non-TCP/IP based network, any LAN or WAN or the like. 
     According to one implementation, each user system  12  and all of its components are operator configurable using applications, such as a browser, including computer code run using a central processing unit such as an Intel Pentium® processor or the like. Similarly, system  16  (and additional instances of an MTS, where more than one is present) and all of its components might be operator configurable using application(s) including computer code to run using processor system  17 , which may be implemented to include a central processing unit, which may include an Intel Pentium® processor or the like, and/or multiple processor units. Non-transitory computer-readable media can have instructions stored thereon/in, that can be executed by or used to program a computing device to perform any of the methods of the implementations described herein. Computer program code  26  implementing instructions for operating and configuring system  16  to intercommunicate and to process web pages, applications and other data and media content as described herein is preferably downloadable and stored on a hard disk, but the entire program code, or portions thereof, may also be stored in any other volatile or non-volatile memory medium or device as is well known, such as a ROM or RAM, or provided on any media capable of storing program code, such as any type of rotating media including floppy disks, optical discs, digital versatile disk (DVD), compact disk (CD), microdrive, and magneto-optical disks, and magnetic or optical cards, nanosystems (including molecular memory ICs), or any other type of computer-readable medium or device suitable for storing instructions and/or data. Additionally, the entire program code, or portions thereof, may be transmitted and downloaded from a software source over a transmission medium, e.g., over the Internet, or from another server, as is well known, or transmitted over any other conventional network connection as is well known (e.g., extranet, VPN, LAN, etc.) using any communication medium and protocols (e.g., TCP/IP, HTTP, HTTPS, Ethernet, etc.) as are well known. It will also be appreciated that computer code for the disclosed implementations can be realized in any programming language that can be executed on a client system and/or server or server system such as, for example, C, C++, HTML, any other markup language, Java™, JavaScript, ActiveX, any other scripting language, such as VBScript, and many other programming languages as are well known may be used. (Java™ is a trademark of Sun Microsystems, Inc.). 
     According to some implementations, each system  16  is configured to provide web pages, forms, applications, data and media content to user (client) systems  12  to support the access by user systems  12  as tenants of system  16 . As such, system  16  provides security mechanisms to keep each tenant&#39;s data separate unless the data is shared. If more than one MTS is used, they may be located in close proximity to one another (e.g., in a server farm located in a single building or campus), or they may be distributed at locations remote from one another (e.g., one or more servers located in city A and one or more servers located in city B). As used herein, each MTS could include one or more logically and/or physically connected servers distributed locally or across one or more geographic locations. Additionally, the term “server” is meant to refer to one type of computing device such as a system including processing hardware and process space(s), an associated storage medium such as a memory device or database, and, in some instances, a database application (e.g., OODBMS or RDBMS) as is well known in the art. It should also be understood that “server system” and “server” are often used interchangeably herein. Similarly, the database objects described herein can be implemented as single databases, a distributed database, a collection of distributed databases, a database with redundant online or offline backups or other redundancies, etc., and might include a distributed database or storage network and associated processing intelligence. 
       FIG. 9B  shows a block diagram of an example of some implementations of elements of  FIG. 9A  and various possible interconnections between these elements. That is,  FIG. 9B  also illustrates environment  10 . However, in  FIG. 9B  elements of system  16  and various interconnections in some implementations are further illustrated.  FIG. 9B  shows that user system  12  may include processor system  12 A, memory system  12 B, input system  12 C, and output system  12 D.  FIG. 9B  shows network  14  and system  16 .  FIG. 9B  also shows that system  16  may include tenant data storage  22 , tenant data  23 , system data storage  24 , system data  25 , User Interface (UI)  30 , Application Program Interface (API)  32 , PL/SOQL  34 , save routines  36 , application setup mechanism  38 , application servers  50   1 - 50   N , system process space  52 , tenant process spaces  54 , tenant management process space  60 , tenant storage space  62 , user storage  64 , and application metadata  66 . In other implementations, environment  10  may not have the same elements as those listed above and/or may have other elements instead of, or in addition to, those listed above. 
     User system  12 , network  14 , system  16 , tenant data storage  22 , and system data storage  24  were discussed above in  FIG. 9A . Regarding user system  12 , processor system  12 A may be any combination of one or more processors. Memory system  12 B may be any combination of one or more memory devices, short term, and/or long term memory. Input system  12 C may be any combination of input devices, such as one or more keyboards, mice, trackballs, scanners, cameras, and/or interfaces to networks. Output system  12 D may be any combination of output devices, such as one or more monitors, printers, and/or interfaces to networks. As shown by  FIG. 9B , system  16  may include a network interface  20  (of  FIG. 9A ) implemented as a set of application servers  50 , an application platform  18 , tenant data storage  22 , and system data storage  24 . Also shown is system process space  52 , including individual tenant process spaces  54  and a tenant management process space  60 . Each application server  50  may be configured to communicate with tenant data storage  22  and the tenant data  23  therein, and system data storage  24  and the system data  25  therein to serve requests of user systems  12 . The tenant data  23  might be divided into individual tenant storage spaces  62 , which can be either a physical arrangement and/or a logical arrangement of data. Within each tenant storage space  62 , user storage  64  and application metadata  66  might be similarly allocated for each user. For example, a copy of a user&#39;s most recently used (MRU) items might be stored to user storage  64 . Similarly, a copy of MRU items for an entire organization that is a tenant might be stored to tenant storage space  62 . A UI  30  provides a user interface and an API  32  provides an application programmer interface to system  16  resident processes to users and/or developers at user systems  12 . The tenant data and the system data may be stored in various databases, such as one or more Oracle® databases. 
     Application platform  18  includes an application setup mechanism  38  that supports application developers&#39; creation and management of applications, which may be saved as metadata into tenant data storage  22  by save routines  36  for execution by subscribers as one or more tenant process spaces  54  managed by tenant management process  60  for example. Invocations to such applications may be coded using PL/SOQL  34  that provides a programming language style interface extension to API  32 . A detailed description of some PL/SOQL language implementations is discussed in commonly assigned U.S. Pat. No. 7,730,478, titled METHOD AND SYSTEM FOR ALLOWING ACCESS TO DEVELOPED APPLICATIONS VIA A MULTI-TENANT ON-DEMAND DATABASE SERVICE, by Craig Weissman, issued on Jun. 1, 2010, and hereby incorporated by reference in its entirety and for all purposes. Invocations to applications may be detected by one or more system processes, which manage retrieving application metadata  66  for the subscriber making the invocation and executing the metadata as an application in a virtual machine. 
     Each application server  50  may be communicably coupled to database systems, e.g., having access to system data  25  and tenant data  23 , via a different network connection. For example, one application server  50   1  might be coupled via the network  14  (e.g., the Internet), another application server  50   N-1  might be coupled via a direct network link, and another application server  50   N  might be coupled by yet a different network connection. Transfer Control Protocol and Internet Protocol (TCP/IP) are typical protocols for communicating between application servers  50  and the database system. However, it will be apparent to one skilled in the art that other transport protocols may be used to optimize the system depending on the network interconnect used. 
     In certain implementations, each application server  50  is configured to handle requests for any user associated with any organization that is a tenant. Because it is desirable to be able to add and remove application servers from the server pool at any time for any reason, there is preferably no server affinity for a user and/or organization to a specific application server  50 . In one implementation, therefore, an interface system implementing a load balancing function (e.g., an F5 Big-IP load balancer) is communicably coupled between the application servers  50  and the user systems  12  to distribute requests to the application servers  50 . In one implementation, the load balancer uses a least connections algorithm to route user requests to the application servers  50 . Other examples of load balancing algorithms, such as round robin and observed response time, also can be used. For example, in certain implementations, three consecutive requests from the same user could hit three different application servers  50 , and three requests from different users could hit the same application server  50 . In this manner, by way of example, system  16  is multi-tenant, wherein system  16  handles storage of, and access to, different objects, data and applications across disparate users and organizations. 
     As an example of storage, one tenant might be a company that employs a sales force where each salesperson uses system  16  to manage their sales process. Thus, a user might maintain contact data, leads data, customer follow-up data, performance data, goals and progress data, etc., all applicable to that user&#39;s personal sales process (e.g., in tenant data storage  22 ). In an example of a MTS arrangement, since all of the data and the applications to access, view, modify, report, transmit, calculate, etc. can be maintained and accessed by a user system having nothing more than network access, the user can manage his or her sales efforts and cycles from any of many different user systems. For example, if a salesperson is visiting a customer and the customer has Internet access in their lobby, the salesperson can obtain critical updates as to that customer while waiting for the customer to arrive in the lobby. 
     While each user&#39;s data might be separate from other users&#39; data regardless of the employers of each user, some data might be organization-wide data shared or accessible by a plurality of users or all of the users for a given organization that is a tenant. Thus, there might be some data structures managed by system  16  that are allocated at the tenant level while other data structures might be managed at the user level. Because an MTS might support multiple tenants including possible competitors, the MTS should have security protocols that keep data, applications, and application use separate. Also, because many tenants may opt for access to an MTS rather than maintain their own system, redundancy, up-time, and backup are additional functions that may be implemented in the MTS. In addition to user-specific data and tenant-specific data, system  16  might also maintain system level data usable by multiple tenants or other data. Such system level data might include industry reports, news, postings, and the like that are sharable among tenants. 
     In certain implementations, user systems  12  (which may be client systems) communicate with application servers  50  to request and/or update system-level or tenant-level data from system  16 , which may involve sending one or more queries to tenant data storage  22  and/or system data storage  24 . System  16  (e.g., an application server  50  in system  16 ) automatically generates one or more SQL statements (e.g., one or more SQL queries) that are designed to access the desired information. System data storage  24  may generate query plans to access the requested data from the database. 
     Each database can generally be viewed as a collection of objects, such as a set of logical tables, containing data fitted into predefined categories. A “table” is one representation of a data object, and may be used herein to simplify the conceptual description of objects and custom objects according to some implementations. It should be understood that “table” and “object” may be used interchangeably herein. Each table generally contains one or more data categories logically arranged as columns or fields in a viewable schema. Each row or record of a table contains an instance of data (e.g., data item) for each category defined by the fields. For example, a CRM database may include a table that describes a customer with fields for basic contact information such as name, address, phone number, fax number, etc. Another table might describe a purchase order, including fields for information such as customer, product, sale price, date, etc. In some multi-tenant database systems, standard entity tables might be provided for use by all tenants. For CRM database applications, such standard entities might include tables for case, account, contact, lead, and opportunity data objects, each containing pre-defined fields. It should be understood that the word “entity” may also be used interchangeably herein with “object” and “table”. 
     In some multi-tenant database systems, tenants may be allowed to create and store custom objects, or they may be allowed to customize standard entities or objects, for example by creating custom fields for standard objects, including custom index fields. Commonly assigned U.S. Pat. No. 7,779,039, titled CUSTOM ENTITIES AND FIELDS IN A MULTI-TENANT DATABASE SYSTEM, by Weissman et al., issued on Aug. 17, 2010, and hereby incorporated by reference in its entirety and for all purposes, teaches systems and methods for creating custom objects as well as customizing standard objects in a multi-tenant database system. In certain implementations, for example, all custom entity data rows are stored in a single multi-tenant physical table, which may contain multiple logical tables per organization. It is transparent to customers that their multiple “tables” are in fact stored in one large table or that their data may be stored in the same table as the data of other customers. 
       FIG. 10A  shows a system diagram of an example of architectural components of an on-demand database service environment  900 , in accordance with some implementations. A client machine located in the cloud  904 , generally referring to one or more networks in combination, as described herein, may communicate with the on-demand database service environment via one or more edge routers  908  and  912 . A client machine can be any of the examples of user systems  12  described above. The edge routers may communicate with one or more core switches  920  and  924  via firewall  916 . The core switches may communicate with a load balancer  928 , which may distribute server load over different pods, such as the pods  940  and  944 . The pods  940  and  944 , which may each include one or more servers and/or other computing resources, may perform data processing and other operations used to provide on-demand services. Communication with the pods may be conducted via pod switches  932  and  936 . Components of the on-demand database service environment may communicate with a database storage  956  via a database firewall  948  and a database switch  952 . 
     As shown in  FIGS. 10A and 10B , accessing an on-demand database service environment may involve communications transmitted among a variety of different hardware and/or software components. Further, the on-demand database service environment  900  is a simplified representation of an actual on-demand database service environment. For example, while only one or two devices of each type are shown in  FIGS. 10A and 10B , some implementations of an on-demand database service environment may include anywhere from one to many devices of each type. Also, the on-demand database service environment need not include each device shown in  FIGS. 10A and 10B , or may include additional devices not shown in  FIGS. 10A and 10B . 
     Moreover, one or more of the devices in the on-demand database service environment  900  may be implemented on the same physical device or on different hardware. Some devices may be implemented using hardware or a combination of hardware and software. Thus, terms such as “data processing apparatus,” “machine,” “server” and “device” as used herein are not limited to a single hardware device, but rather include any hardware and software configured to provide the described functionality. 
     The cloud  904  is intended to refer to a data network or combination of data networks, often including the Internet. Client machines located in the cloud  904  may communicate with the on-demand database service environment to access services provided by the on-demand database service environment. For example, client machines may access the on-demand database service environment to retrieve, store, edit, and/or process information. 
     In some implementations, the edge routers  908  and  912  route packets between the cloud  904  and other components of the on-demand database service environment  900 . The edge routers  908  and  912  may employ the Border Gateway Protocol (BGP). The BGP is the core routing protocol of the Internet. The edge routers  908  and  912  may maintain a table of IP networks or ‘prefixes’, which designate network reachability among autonomous systems on the Internet. 
     In one or more implementations, the firewall  916  may protect the inner components of the on-demand database service environment  900  from Internet traffic. The firewall  916  may block, permit, or deny access to the inner components of the on-demand database service environment  900  based upon a set of rules and other criteria. The firewall  916  may act as one or more of a packet filter, an application gateway, a stateful filter, a proxy server, or any other type of firewall. 
     In some implementations, the core switches  920  and  924  are high-capacity switches that transfer packets within the on-demand database service environment  900 . The core switches  920  and  924  may be configured as network bridges that quickly route data between different components within the on-demand database service environment. In some implementations, the use of two or more core switches  920  and  924  may provide redundancy and/or reduced latency. 
     In some implementations, the pods  940  and  944  may perform the core data processing and service functions provided by the on-demand database service environment. Each pod may include various types of hardware and/or software computing resources. An example of the pod architecture is discussed in greater detail with reference to  FIG. 10B . 
     In some implementations, communication between the pods  940  and  944  may be conducted via the pod switches  932  and  936 . The pod switches  932  and  936  may facilitate communication between the pods  940  and  944  and client machines located in the cloud  904 , for example via core switches  920  and  924 . Also, the pod switches  932  and  936  may facilitate communication between the pods  940  and  944  and the database storage  956 . 
     In some implementations, the load balancer  928  may distribute workload between the pods  940  and  944 . Balancing the on-demand service requests between the pods may assist in improving the use of resources, increasing throughput, reducing response times, and/or reducing overhead. The load balancer  928  may include multilayer switches to analyze and forward traffic. 
     In some implementations, access to the database storage  956  may be guarded by a database firewall  948 . The database firewall  948  may act as a computer application firewall operating at the database application layer of a protocol stack. The database firewall  948  may protect the database storage  956  from application attacks such as structure query language (SQL) injection, database rootkits, and unauthorized information disclosure. 
     In some implementations, the database firewall  948  may include a host using one or more forms of reverse proxy services to proxy traffic before passing it to a gateway router. The database firewall  948  may inspect the contents of database traffic and block certain content or database requests. The database firewall  948  may work on the SQL application level atop the TCP/IP stack, managing applications&#39; connection to the database or SQL management interfaces as well as intercepting and enforcing packets traveling to or from a database network or application interface. 
     In some implementations, communication with the database storage  956  may be conducted via the database switch  952 . The multi-tenant database storage  956  may include more than one hardware and/or software components for handling database queries. Accordingly, the database switch  952  may direct database queries transmitted by other components of the on-demand database service environment (e.g., the pods  940  and  944 ) to the correct components within the database storage  956 . 
     In some implementations, the database storage  956  is an on-demand database system shared by many different organizations. The on-demand database service may employ a multi-tenant approach, a virtualized approach, or any other type of database approach. On-demand database services are discussed in greater detail with reference to  FIG. 10B . 
       FIG. 10B  shows a system diagram further illustrating an example of architectural components of an on-demand database service environment, in accordance with some implementations. The pod  944  may be used to render services to a user of the on-demand database service environment  900 . In some implementations, each pod may include a variety of servers and/or other systems. The pod  944  includes one or more content batch servers  964 , content search servers  968 , query servers  982 , file servers  986 , access control system (ACS) servers  980 , batch servers  984 , and app servers  988 . Also, the pod  944  includes database instances  990 , quick file systems (QFS)  992 , and indexers  994 . In one or more implementations, some or all communication between the servers in the pod  944  may be transmitted via the switch  936 . 
     The content batch servers  964  may handle requests internal to the pod. These requests may be long-running and/or not tied to a particular customer. For example, the content batch servers  964  may handle requests related to log mining, cleanup work, and maintenance tasks. 
     The content search servers  968  may provide query and indexer functions. For example, the functions provided by the content search servers  968  may allow users to search through content stored in the on-demand database service environment. 
     The file servers  986  may manage requests for information stored in the file storage  998 . The file storage  998  may store information such as documents, images, and basic large objects (BLOBs). By managing requests for information using the file servers  986 , the image footprint on the database may be reduced. 
     The query servers  982  may be used to retrieve information from one or more file systems. For example, the query system  982  may receive requests for information from the app servers  988  and then transmit information queries to the NFS  996  located outside the pod. 
     The pod  944  may share a database instance  990  configured as a multi-tenant environment in which different organizations share access to the same database. Additionally, services rendered by the pod  944  may call upon various hardware and/or software resources. In some implementations, the ACS servers  980  may control access to data, hardware resources, or software resources. 
     In some implementations, the batch servers  984  may process batch jobs, which are used to run tasks at specified times. Thus, the batch servers  984  may transmit instructions to other servers, such as the app servers  988 , to trigger the batch jobs. 
     In some implementations, the QFS  992  may be an open source file system available from Sun Microsystems® of Santa Clara, Calif. The QFS may serve as a rapid-access file system for storing and accessing information available within the pod  944 . The QFS  992  may support some volume management capabilities, allowing many disks to be grouped together into a file system. File system metadata can be kept on a separate set of disks, which may be useful for streaming applications where long disk seeks cannot be tolerated. Thus, the QFS system may communicate with one or more content search servers  968  and/or indexers  994  to identify, retrieve, move, and/or update data stored in the network file systems  996  and/or other storage systems. 
     In some implementations, one or more query servers  982  may communicate with the NFS  996  to retrieve and/or update information stored outside of the pod  944 . The NFS  996  may allow servers located in the pod  944  to access information to access files over a network in a manner similar to how local storage is accessed. 
     In some implementations, queries from the query servers  922  may be transmitted to the NFS  996  via the load balancer  928 , which may distribute resource requests over various resources available in the on-demand database service environment. The NFS  996  may also communicate with the QFS  992  to update the information stored on the NFS  996  and/or to provide information to the QFS  992  for use by servers located within the pod  944 . 
     In some implementations, the pod may include one or more database instances  990 . The database instance  990  may transmit information to the QFS  992 . When information is transmitted to the QFS, it may be available for use by servers within the pod  944  without using an additional database call. 
     In some implementations, database information may be transmitted to the indexer  994 . Indexer  994  may provide an index of information available in the database  990  and/or QFS  992 . The index information may be provided to file servers  986  and/or the QFS  992 . 
     In some implementations, one or more application servers or other servers described above with reference to  FIGS. 8A and 8B  include a hardware and/or software framework configurable to execute procedures using programs, routines, scripts, etc. Thus, in some implementations, one or more of application servers  50   1 - 50   N  of  FIG. 9B  can be configured to initiate performance of one or more of the operations described above with reference to  FIGS. 1A-7D  by instructing another computing device to perform an operation. In some implementations, one or more application servers  50   1 - 50   N  carry out, either partially or entirely, one or more of the disclosed operations described with reference to  FIGS. 1A-7D . In some implementations, app servers  988  of  FIG. 10B  support the construction of applications provided by the on-demand database service environment  900  via the pod  944 . Thus, an app server  988  may include a hardware and/or software framework configurable to execute procedures to partially or entirely carry out or instruct another computing device to carry out one or more operations disclosed herein, including operations described above with reference to  FIG. 5  In alternative implementations, two or more app servers  988  may cooperate to perform or cause performance of such operations. Any of the databases and other storage facilities described above with reference to  FIGS. 9A, 9B, 10A and 10B  can be configured to store lists, articles, documents, records, files, and other objects for implementing the operations described above with reference to  FIG. 5 . For instance, lists of published fields associated with corresponding connections can be maintained in tenant data storage  22  and/or system data storage  24  of  FIGS. 9A and 9B . In some other implementations, rather than storing one or more lists, articles, documents, records, and/or files, the databases and other storage facilities described above can store pointers to the lists, articles, documents, records, and/or files, which may instead be stored in other repositories external to the systems and environments described above with reference to  FIGS. 9A, 9B, 10A and 10B . 
     While some of the disclosed implementations may be described with reference to a system having an application server providing a front end for an on-demand database service capable of supporting multiple tenants, the disclosed implementations are not limited to multi-tenant databases nor deployment on application servers. Some implementations may be practiced using various database architectures such as ORACLE®, DB2® by IBM and the like without departing from the scope of the implementations claimed. 
     It should be understood that some of the disclosed implementations can be embodied in the form of control logic using hardware and/or computer software in a modular or integrated manner. Other ways and/or methods are possible using hardware and a combination of hardware and software. 
     Any of the disclosed implementations may be embodied in various types of hardware, software, firmware, and combinations thereof. For example, some techniques disclosed herein may be implemented, at least in part, by computer-readable media that include program instructions, state information, etc., for performing various services and operations described herein. Examples of program instructions include both machine code, such as produced by a compiler, and files containing higher-level code that may be executed by a computing device such as a server or other data processing apparatus using an interpreter. Examples of computer-readable media include, but are not limited to: magnetic media such as hard disks, floppy disks, and magnetic tape; optical media such as flash memory, compact disk (CD) or digital versatile disk (DVD); magneto-optical media; and hardware devices specially configured to store program instructions, such as read-only memory (ROM) devices and random access memory (RAM) devices. A computer-readable medium may be any combination of such storage devices. 
     Any of the operations and techniques described in this application may be implemented as software code to be executed by a processor using any suitable computer language such as, for example, Java, C++ or Perl using, for example, object-oriented techniques. The software code may be stored as a series of instructions or commands on a computer-readable medium. Computer-readable media encoded with the software/program code may be packaged with a compatible device or provided separately from other devices (e.g., via Internet download). Any such computer-readable medium may reside on or within a single computing device or an entire computer system, and may be among other computer-readable media within a system or network. A computer system or computing device may include a monitor, printer, or other suitable display for providing any of the results mentioned herein to a user. 
     While various implementations have been described herein, it should be understood that they have been presented by way of example only, and not limitation. Thus, the breadth and scope of the present application should not be limited by any of the implementations described herein, but should be defined only in accordance with the following and later-submitted claims and their equivalents.