X-Git-Url: http://www.git.cypherpunks.ru/?p=govpn.git;a=blobdiff_plain;f=doc%2Ftransport.texi;h=e5f5abba9eba15dec245489f2aa53c807d007b5f;hp=812322528f03019d4b882dab6e925ebdd386afa4;hb=0bf04621961589bc735dc8bd8a075d7db24c4178;hpb=c6a35dfd54ce509db91c4430b0207ac5c91b1bea diff --git a/doc/transport.texi b/doc/transport.texi index 8123225..e5f5abb 100644 --- a/doc/transport.texi +++ b/doc/transport.texi @@ -2,7 +2,7 @@ @section Transport protocol @verbatim - NONCE = 64bit(MAC(MAC_KEY, SERIAL)) + NONCE = 64bit(ZEROS) || 64bit(MAC(MAC_KEY, SERIAL)) PAYLOAD = DATA || PAD [|| ZEROS] CIPHERTEXT = ENCRYPT(KEY, NONCE, PAYLOAD) TAG = AUTH(AUTH_KEY, CIPHERTEXT || NONCE) @@ -13,16 +13,16 @@ CIPHERTEXT = ENCRYPT(KEY, NONCE, PAYLOAD) client (to server) messages, evens for server (to client) messages. @code{MAC} is BLAKE2b-MAC used to obfuscate @code{SERIAL}. MAC's key -@code{MAC_KEY} is the first 256-bit of Salsa20's output with established +@code{MAC_KEY} is the first 256-bit of ChaCha20's output with established common key and zero nonce (message nonces start from 1). @verbatim MAC_KEY = 256bit(ENCRYPT(KEY, 0)) @end verbatim -@code{ENCRYPT} is Salsa20 stream cipher, with established session +@code{ENCRYPT} is ChaCha20 stream cipher, with established session @code{KEY} and obfuscated @code{SERIAL} used as a nonce. 512 bit of -Salsa20's output is ignored and only remaining is XORed with ther data, +ChaCha20's output is ignored and only remaining is XORed with ther data, encrypting it. @code{DATA} is padded using ISO/IEC 7816-4 format (@code{PAD} (0x80 @@ -30,7 +30,7 @@ byte) with optional @code{ZEROS} following), to fill up packet to conceal payload packet length. @code{AUTH} is Poly1305 authentication function. First 256 bits of -Salsa20's output are used as a one-time key for @code{AUTH}. +ChaCha20's output are used as a one-time key for @code{AUTH}. @verbatim AUTH_KEY = 256bit(ENCRYPT(KEY, NONCE))