Bulletproof TLS Newsletter #75
IETF formally deprecates TLS 1.0 and 1.1
31 Mar 2021
Author: Hanno Böck

This issue was distributed to 56,278 email subscribers.

Bulletproof TLS Newsletter is a free periodic newsletter bringing you commentary and news surrounding SSL/TLS and Internet PKI, designed to keep you informed about the latest developments in this space.

In this issue:

  1. IETF formally deprecates TLS 1.0 and 1.1
  2. Short news

IETF formally deprecates TLS 1.0 and 1.1

The Internet Engineering Task Force has published RFC 8996, which officially deprecates the old TLS versions 1.0 and 1.1. These old versions have inherent security weaknesses that can only be fixed by moving to a newer protocol version.

This move is not a surprise; it merely codifies what is already widespread practice. Back in late 2018, all major browser vendors announced plans to deprecate these old TLS versions, and web clients today usually don’t initiate connections with TLS 1.0 and 1.1.

Together with the old TLS versions, two other RFCs are marked as obsolete. One is RFC 5469, which specifies DES and IDEA cipher suites that were never allowed within TLS 1.2 and thus are no longer usable. The other is RFC 7507, which specifies a downgrade protection mechanism called Signaling Cipher Suite Value (SCSV) that was used to prevent client downgrades to previous TLS versions on connection failures. TLS 1.3 introduced a different version negotiation and downgrade protection mechanism and thus made SCSV obsolete.

Short news


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