From 05855bf2ce7d5cd0a6db18bc0b4214ed5ef7516d Mon Sep 17 00:00:00 2001 From: "djm@openbsd.org" Date: Tue, 3 May 2016 13:10:24 +0000 Subject: upstream commit clarify ordering of subkeys; pointed out by ietf-ssh AT stbuehler.de Upstream-ID: 05ebe9f949449a555ebce8e0aad7c8c9acaf8463 --- PROTOCOL.chacha20poly1305 | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'PROTOCOL.chacha20poly1305') diff --git a/PROTOCOL.chacha20poly1305 b/PROTOCOL.chacha20poly1305 index 9cf73a92..4857d385 100644 --- a/PROTOCOL.chacha20poly1305 +++ b/PROTOCOL.chacha20poly1305 @@ -34,6 +34,8 @@ Detailed Construction The chacha20-poly1305@openssh.com cipher requires 512 bits of key material as output from the SSH key exchange. This forms two 256 bit keys (K_1 and K_2), used by two separate instances of chacha20. +The first 256 bits consitute K_2 and the second 256 bits become +K_1. The instance keyed by K_1 is a stream cipher that is used only to encrypt the 4 byte packet length field. The second instance, @@ -101,5 +103,5 @@ References [3] "ChaCha20 and Poly1305 based Cipher Suites for TLS", Adam Langley http://tools.ietf.org/html/draft-agl-tls-chacha20poly1305-03 -$OpenBSD: PROTOCOL.chacha20poly1305,v 1.2 2013/12/02 02:50:27 djm Exp $ +$OpenBSD: PROTOCOL.chacha20poly1305,v 1.3 2016/05/03 13:10:24 djm Exp $ -- cgit v1.2.1