Code change:
Addressing Roman's AD comments.
has 2 conflicts, not sure how to resolve, the updates look fine. Please merge.
There was a conflict with the 8174 reference being in the other branch. I added it in because it's now part of the terminology paragraph.
Please address the following IDNits: -- The document seems to lack an IANA Considerations section. (See Section 2.2 of URL for how to handle the case when there are no actions for IANA.) -- The draft header indicates that this document updates RFC5246, but the abstract doesn't seem to mention this, which it should. -- The draft header indicates that this document updates RFC7525, but the abstract doesn't seem to mention this, which it should. Section 1. Editorial. -- s/RFC 5246 [RFC5246]/[RFC5246]/ -- s/RFC 6151 [RFC6151]/[RFC6151]/ -- s/RFC7525 [RFC7525]/[RFC7525]/ Section 1. Editorial. For symmetry with the rest of the text: OLD RFC 6151 [RFC6151] details the security considerations, including collision attacks for MD5, published in 2011. NEW In 2011, [RFC6151] detailed the security considerations, including collision attacks for MD5. Section 1. Please provide a reference for "Wang, et al". Is there a reference to provide for the "the potential for brute-force attack" Section 6. Editorial Nit. s/RFC5246 [RFC5246]/[RFC5246]/ Section 6. Move the text "In Section 7.4.1.4.1: the text should be revised from" out of the "OLD" block of text to be its own intro paragraph so that the OLD vs. NEW is a clear cut-and-paste. Section 7. Editorial. s/ RFC7525 [RFC7525]/[RFC7525]/ Section 7. SHA-1 is also not mentioned in RFC7525. Recommend: OLD The prior text did not explicitly include MD5 and this text adds it to ensure it is understood as having been deprecated. NEW The prior text did not explicitly include MD5 or SHA-1; and this text adds guidance to ensure that these algorithms have been deprecated. Section 7. Editorial. Grammar. OLD In addition, the use of the SHA-256 hash algorithm is RECOMMENDED, SHA-1 or MD5 MUST NOT be used NEW In addition, the use of the SHA-256 hash algorithm is RECOMMENDED; and SHA-1 or MD5 MUST NOT be used Section 10.2 Please make RFC5246 a normative reference.

Related discussion:
text: The MD5 and SHA-1 hashing algorithms are steadily weakening in strength and their deprecation process should begin for their use in TLS 1.2 digital signatures.  However, this document does not <del> deprecate SHA-1 in HMAC for record protection. </del> <ins> deprecate SHA-1 in HMAC for record protection.  This document updates RFC 5246 and RFC 7525. </ins> 1. The usage of MD5 and SHA-1 for signature hashing in TLS 1.2 is specified in RFC5246.  MD5 and SHA-1 have been proven to be insecure, <del> subject to collision attacks.  RFC6151 details the security considerations, including collision attacks for MD5, published in 2011.  NIST formally deprecated use of SHA-1 in 2011 NISTSP800-131A-R2 and disallowed its use for digital signatures at the end of 2013, based on both the Wang, et. al, attack and the potential for brute-force attack.  In 2016, researchers from INRIA identified a new class of transcript collision attacks on TLS (and other protocols) that rely on efficient collision-finding algorithms on the underlying hash constructions Transcript-Collision.  Further, in 2017, researchers from Google and CWI Amsterdam SHA-1-Collision proved SHA-1 collision attacks were practical.  This document updates RFC5246 and RFC7525 in such a way that MD5 and SHA-1 MUST NOT be used for digital signatures.  However, this document does not deprecate SHA-1 in HMAC for record protection. </del> <ins> subject to collision attacks Wang.  In 2011, RFC6151 detailed the security considerations, including collision attacks for MD5.  NIST formally deprecated use of SHA-1 in 2011 NISTSP800-131A-R2 and disallowed its use for digital signatures at the end of 2013, based on both the Wang, et. al, attack and the potential for brute-force attack.  In 2016, researchers from INRIA identified a new class of transcript collision attacks on TLS (and other protocols) that rely on efficient collision-finding algorithms on the underlying hash constructions Transcript-Collision.  Further, in 2017, researchers from Google and CWI Amsterdam SHA-1-Collision proved SHA-1 collision attacks were practical.  This document updates RFC5246 and RFC7525 in such a way that MD5 and SHA-1 MUST NOT be used for digital signatures.  However, this document does not deprecate SHA-1 in HMAC for record protection. </ins> 1.1. The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", <del> "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC2119. </del> <ins> "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 RFC2119 RFC8174 when, and only when, they appear in all capitals, as shown here. </ins> 2.