Obsolete ADLER-32 but don't forbid it. #828

draft-ietf-httpbis-digest-headers.md

@@ -26,7 +26,9 @@ author:
 
 normative:
   RFC1321:
+  RFC1950:
   RFC3230:
+  RFC3309:
   RFC2119:
   RFC5789:
   RFC5843:
@@ -674,6 +676,12 @@ However, these rely on collision-resistance for their security proofs [CMU-83606
 The MD5 and SHA-1 algorithms are vulnerable to collisions attacks and 
 they are NOT RECOMMENDED.
 
+## Other deprecated algorithms
+
+The ADLER32 algorithm defined in [RFC1950] has been deprecated
+by [RFC3309] because under certain conditions it provides
+weak detection of errors and is now NOT RECOMMENDED.
+
 ## Digest for end-to-end integrity
 
 `Digest` alone does not provide end-to-end integrity
@@ -760,6 +768,20 @@ registry:
 * Description: As specified in {{algorithms}}.
 * Status: As specified in {{algorithms}}.
 
+## Obsolete "ADLER32" Digest Algorithm {#iana-adler-32}
+
+This memo updates the "ADLER32" digest algorithm in the [HTTP Digest
+Algorithm
+Values](https://www.iana.org/assignments/http-dig-alg/http-dig-alg.xhtml)
+registry:
+
+* Digest Algorithm: ADLER32
+* Description: The ADLER32 algorithm is a checksum specified in [RFC1950] "ZLIB Compressed Data Format".
+  The 32-bit output is encoded in hexadecimal (using between 1 and 8 ASCII characters from 0-9, A-F, and a-f; leading 0's are allowed).
+  For example, ADLER32=03da0195 and ADLER32=3DA0195 are both valid checksums for the 4-byte message "Wiki".
+  This algorithm is obsoleted and SHOULD NOT be used.
+* Status: obsoleted
+
 ## The "ID-SHA-256" Digest Algorithm {#iana-ID-SHA-256}
 
 This memo registers the "ID-SHA-256" digest algorithm in the [HTTP Digest