Change:
such as a SIM card; or interacting with a user, such as password prompting. <del> 3.8.3.2. </del> <ins> 3.4.3.2. </ins> Since ESP is below transport protocols, it does not have any dependencies on the transports themselves, other than on UDP or TCP where encapsulation is employed. <del> 3.9. </del> <ins> 3.5. </ins> <del> WireGuard is a layer 3 protocol designed to complement or replace IPsec WireGuard.  Unlike most transport security protocols, which rely on PKI for peer authentication, WireGuard authenticates peers using pre-shared public keys delivered out-of-band, each of which is bound to one or more IP addresses.  Moreover, as a protocol suited for VPNs, WireGuard offers no extensibility, negotiation, or cryptographic agility. </del> <ins> SRTP - Secure RTP - is a profile for RTP that provides confidentiality, message authentication, and replay protection for data and control packets RFC3711.  SRTP packets are encrypted using a session key, which is derived from a separate master key.  Master keys are derived and managed externally, e.g., via DTLS, as specified in RFC 5763 RFC5763, under the control of a signaling protocol such as SIP RFC3261 or WebRTC I-D.ietf-rtcweb-security-arch. </ins> <del> 3.9.1. </del> <ins> 3.5.1. </ins> <del> WireGuard is a simple VPN protocol that binds a pre-shared public key to one or more IP addresses.  Users configure WireGuard by associating peer public keys with IP addresses.  These mappings are stored in a CryptoKey Routing Table.  (See Section 2 of WireGuard for more details and sample configurations.)  These keys are used upon WireGuard packet transmission and reception.  For example, upon receipt of a Handshake Initiation message, receivers use the static public key in their CryptoKey routing table to perform necessary cryptographic computations. </del> <ins> SRTP adds confidentiality and optional integrity protection to RTP data packets, and adds confidentially and mandatory integrity protection to RTP control (RTCP) packets.  For RTP data packets, this is done by encrypting the payload section of the packet and optionally appending an authentication tag (MAC) as a packet trailer, with the RTP header authenticated but not encrypted.  The RTP header itself is left unencrypted to enable RTP header compression RFC3545. For RTCP packets, the first packet in the compound RTCP packet is partially encrypted, leaving the first eight octets of the header as cleartext to allow identification of the packet as RTCP, while the remainder of the compound packet is fully encrypted.  The entire RTCP packet is then authenticated by appending a MAC as packet trailer. Packets are encrypted using session keys, which are ultimately derived from a master key and some additional master salt and session salt.  SRTP packets carry a 2-byte sequence number to partially identify the unique packet index.  SRTP peers maintain a separate rollover counter (ROC) for RTP data packets that is incremented whenever the sequence number wraps.  The sequence number and ROC together determine the packet index.  RTCP packets have a similar, yet differently named, field called the RTCP index which serves the same purpose. Numerous encryption modes are supported.  For popular modes of operation, e.g., AES-CTR, the (unique) initialization vector (IV) used for each encryption mode is a function of the RTP SSRC (synchronization source), packet index, and session "salting key". SRTP offers replay detection by keeping a replay list of already seen and processed packet indices.  If a packet arrives with an index that matches one in the replay list, it is silently discarded. DTLS RFC5764 is commonly used as a way to perform mutual authentication and key agreement for SRTP RFC5763.  (Here, certificates marshal public keys between endpoints.  Thus, self- signed certificates may be used if peers do not mutually trust one another, as is common on the Internet.)  When DTLS is used, certificate fingerprints are transmitted out-of-band using SIP. Peers typically verify that DTLS-offered certificates match that which are offered over SIP.  This prevents active attacks on RTP, but not on the signaling (SIP or WebRTC) channel. 3.5.2. Optional replay protection with tunable replay windows. Out-of-order packet receipt. (RFC5763) Mandatory mutually authenticated key exchange. Partial encryption, protecting media payloads and control packets but not data packet headers. Optional authentication of data packets; mandatory authentication of control packets. 3.5.3. External key derivation and management mechanism or protocol, e.g., DTLS RFC5763. External signaling protocol to manage RTP parameters and locate and identify peers, e.g., SIP RFC3261 or WebRTC I-D.ietf-rtcweb- security-arch. 3.6. ((TODO: write me)) 3.7. Tcpcrypt is a lightweight extension to the TCP protocol to enable opportunistic encryption with hooks available to the application layer for implementation of endpoint authentication. 3.7.1. Tcpcrypt extends TCP to enable opportunistic encryption between the two ends of a TCP connection I-D.ietf-tcpinc-tcpcrypt.  It is a family of TCP encryption protocols (TEP), distinguished by key exchange algorithm.  The use of a TEP is negotiated with a TCP option during the initial TCP handshake via the mechanism described by TCP Encryption Negotiation Option (ENO) I-D.ietf-tcpinc-tcpeno.  In the case of initial session establishment, once a tcpcrypt TEP has been negotiated the key exchange occurs within the data segments of the first few packets exchanged after the handshake completes.  The initiator of a connection sends a list of supported AEAD algorithms, a random nonce, and an ephemeral public key share.  The responder typically chooses a mutually-supported AEAD algorithm and replies with this choice, its own nonce, and ephemeral key share.  An initial shared secret is derived from the ENO handshake, the tcpcrypt handshake, and the initial keying material resulting from the key exchange.  The traffic encryption keys on the initial connection are derived from the shared secret.  Connections can be re-keyed before the natural AEAD limit for a single set of traffic encryption keys is reached. Each tcpcrypt session is associated with a ladder of resumption IDs, each derived from the respective entry in a ladder of shared secrets. These resumption IDs can be used to negotiate a stateful resumption of the session in a subsequent connection, resulting in use of a new shared secret and traffic encryption keys without requiring a new key exchange.  Willingness to resume a session is signaled via the ENO option during the TCP handshake.  Given the length constraints imposed by TCP options, unlike stateless resumption mechanisms (such as that provided by session tickets in TLS) resumption in tcpcrypt requires the maintenance of state on the server, and so successful resumption across a pool of servers implies shared state. Owing to middlebox ossification issues, tcpcrypt only protects the payload portion of a TCP packet.  It does not encrypt any header information, such as the TCP sequence number. Tcpcrypt exposes a universally-unique connection-specific session ID to the application, suitable for application-level endpoint authentication either in-band or out-of-band. 3.7.2. Forward-secure TCP payload encryption and integrity protection. Session caching and address-agnostic resumption. Connection re-keying. Application-level authentication primitive. 3.7.3. TCP TCP Encryption Negotiation Option (ENO) 3.8. WireGuard is a layer 3 protocol designed to complement or replace IPsec WireGuard.  Unlike most transport security protocols, which rely on PKI for peer authentication, WireGuard authenticates peers using pre-shared public keys delivered out-of-band, each of which is bound to one or more IP addresses.  Moreover, as a protocol suited for VPNs, WireGuard offers no extensibility, negotiation, or cryptographic agility. 3.8.1. WireGuard is a simple VPN protocol that binds a pre-shared public key to one or more IP addresses.  Users configure WireGuard by associating peer public keys with IP addresses.  These mappings are stored in a CryptoKey Routing Table.  (See Section 2 of WireGuard for more details and sample configurations.)  These keys are used upon WireGuard packet transmission and reception.  For example, upon receipt of a Handshake Initiation message, receivers use the static public key in their CryptoKey routing table to perform necessary cryptographic computations. </ins> WireGuard builds on Noise Noise for 1-RTT key exchange with identity hiding.  The handshake hides peer identities as per the SIGMA

Discussion:
Sort the protocols we describe based on perceived importance, popularity, etc. Basically, put non-standard ones at the end, and all else towards the front.
Correct!
I'm assuming the content itself hasn't changed, just moved around? It's not obvious from the diff, so LMK if not and I'll un-approve.