Re: [TLS] draft-ietf-tls-rfc4492bis-15 and the X25519 significant bit.
Brian Smith <brian@briansmith.org> Wed, 15 March 2017 21:33 UTC
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From: Brian Smith <brian@briansmith.org>
Date: Wed, 15 Mar 2017 11:32:47 -1000
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To: David Benjamin <davidben@chromium.org>
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Subject: Re: [TLS] draft-ietf-tls-rfc4492bis-15 and the X25519 significant bit.
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David Benjamin <davidben@chromium.org> wrote: > draft-ietf-tls-rfc4492bis-15, section 5.11, contains the following text: > > Since there are some implementation of the X25519 function that > impose this restriction on their input and others that don't, > implementations of X25519 in TLS SHOULD reject public keys when the > high-order bit of the final byte is set (in other words, when the > value of the rightmost byte is greater than 0x7F) in order to prevent > implementation fingerprinting. Note that this deviates from RFC 7748 > which suggests that This value be masked. > > https://tools.ietf.org/html/draft-ietf-tls-rfc4492bis-15#section-5.11 > > There was a thread about this way back, but it seems not to have come to a > clear conclusion: > https://www.ietf.org/mail-archive/web/tls/current/msg18821.html Although I argued in favor of a different alternative in that previous thread, given how RFC 7748 ended up, I agree with your suggested change, to align with RFC 7748. Cheers, Brian -- https://briansmith.org/
- [TLS] draft-ietf-tls-rfc4492bis-15 and the X25519… David Benjamin
- Re: [TLS] draft-ietf-tls-rfc4492bis-15 and the X2… Eric Rescorla
- Re: [TLS] draft-ietf-tls-rfc4492bis-15 and the X2… David Benjamin
- Re: [TLS] draft-ietf-tls-rfc4492bis-15 and the X2… Salz, Rich
- Re: [TLS] draft-ietf-tls-rfc4492bis-15 and the X2… Brian Smith