介绍

ESP和AH是通过IPsec进行加密保护的机制。

The Encapsulating Security Payload (ESP) [RFC4303] and the Authentication Header (AH) [RFC4302] are the mechanisms for applying cryptographic protection to data being sent over an IPsec Security Association (SA) [RFC4301].

背景

老的加密算法总是会被新的取代。

The field of cryptography evolves continuously: new, stronger algorithms appear, and existing algorithms are found to be less secure than originally thought. Therefore, algorithm implementation requirements and usage guidance need to be updated from time to time to reflect the new reality.

加密必须认证

Encryption Must Be Authenticated

   Encryption without authentication is not effective and MUST NOT be used.  IPsec offers three ways to provide both encryption and authentication:

   o  ESP with an Authenticated Encryption with Associated Data (AEAD) cipher

   o  ESP with a non-AEAD cipher + authentication

   o  ESP with a non-AEAD cipher + AH with authentication

5. ESP Encryption Algorithms

    +-------------------------+------------+---------+----------------+
    | Name                    | Status     | AEAD    | Comment        |
    +-------------------------+------------+---------+----------------+
    | ENCR_DES_IV64           | MUST NOT   | No      | UNSPECIFIED    |
    | ENCR_DES                | MUST NOT   | No      | [RFC2405]      |
    | ENCR_3DES               | SHOULD NOT | No      | [RFC2451]      |
    | ENCR_BLOWFISH           | MUST NOT   | No      | [RFC2451]      |
    | ENCR_3IDEA              | MUST NOT   | No      | UNSPECIFIED    |
    | ENCR_DES_IV32           | MUST NOT   | No      | UNSPECIFIED    |
    | ENCR_NULL               | MUST       | No      | [RFC2410]      |
    | ENCR_AES_CBC            | MUST       | No      | [RFC3602][1]   |
    | ENCR_AES_CCM_8          | SHOULD     | Yes     | [RFC4309](IoT) |
    | ENCR_AES_GCM_16         | MUST       | Yes     | [RFC4106][1]   |
    | ENCR_CHACHA20_POLY1305  | SHOULD     | Yes     | [RFC7634]      |
    +-------------------------+------------+---------+----------------+

6. ESP and AH Authentication Algorithms

   Authentication algorithm recommendations in this section are
   targeting two types of communications:

   o  Authenticated-only communications without encryption, such as ESP
      with NULL encryption or AH communications.

   o  Communications that are encrypted with a non-AEAD algorithm that
      MUST be combined with an authentication algorithm.

   +------------------------+----------------+-------------------------+
   | Name                   | Status         | Comment                 |
   +------------------------+----------------+-------------------------+
   | AUTH_NONE              | MUST /         | [RFC7296][RFC5282]      |
   |                        | MUST NOT       | AEAD-only               |
   | AUTH_HMAC_MD5_96       | MUST NOT       | [RFC2403][RFC7296]      |
   | AUTH_HMAC_SHA1_96      | MUST-          | [RFC2404][RFC7296]      |
   | AUTH_DES_MAC           | MUST NOT       | UNSPECIFIED             |
   | AUTH_KPDK_MD5          | MUST NOT       | UNSPECIFIED             |
   | AUTH_AES_XCBC_96       | SHOULD / MAY   | [RFC3566][RFC7296]      |
   |                        |                | (IoT)                   |
   | AUTH_AES_128_GMAC      | MAY            | [RFC4543]               |
   | AUTH_AES_256_GMAC      | MAY            | [RFC4543]               |
   | AUTH_HMAC_SHA2_256_128 | MUST           | [RFC4868]               |
   | AUTH_HMAC_SHA2_512_256 | SHOULD         | [RFC4868]               |
   +------------------------+----------------+-------------------------+

7.  ESP and AH Compression Algorithms

                +----------------+----------+-------------+
                | Name           | Status   | Comment     |
                +----------------+----------+-------------+
                | IPCOMP_OUI     | MUST NOT | UNSPECIFIED |
                | IPCOMP_DEFLATE | MAY      | [RFC3173]   |
                | IPCOMP_LZS     | MAY      | [RFC2395]   |
                | IPCOMP_LZJH    | MAY      | [RFC3051]   |
                +----------------+----------+-------------+

8.  Summary of Changes from RFC 7321

   The following table summarizes the changes from RFC 7321.

            +-------------------+----------+-----------------+
            | Algorithm         | RFC 7321 |     RFC 8221    |
            +-------------------+----------+-----------------+
            | ENCR_AES_GCM_16   | SHOULD+  |       MUST      |
            | ENCR_AES_CCM_8    |   MAY    |      SHOULD     |
            | ENCR_AES_CTR      |   MAY    |      MAY(*)     |
            | ENCR_3DES         |   MAY    |    SHOULD NOT   |
            | AUTH_HMAC_SHA1_96 |   MUST   |      MUST-      |
            | AUTH_AES_128_GMAC | SHOULD+  |       MAY       |
            | AUTH_NONE         |   MAY    | MUST / MUST NOT |
            +-------------------+----------+-----------------+