commit 81702d1d830a81b4920cd04851d43e3e5eb1ba27 Author: Nick Mathewson <nickm@torproject.org> Date: Wed Mar 13 23:30:23 2013 -0400 Make it more explicit that everything in tor-spec is big-endian Clarify what we mean when we talk about the MSB of a big-endian value. --- tor-spec.txt | 15 +++++++++++++-- 1 files changed, 13 insertions(+), 2 deletions(-) diff --git a/tor-spec.txt b/tor-spec.txt index 9aea142..b9834bc 100644 --- a/tor-spec.txt +++ b/tor-spec.txt @@ -33,10 +33,17 @@ see tor-design.pdf. [A0 B1 C2] -- a three-byte sequence, containing the bytes with hexadecimal values A0, B1, and C2, in that order. - All numeric values are encoded in network (big-endian) order. - H(m) -- a cryptographic hash of m. + We use "byte" and "octet" interchangeably. Possibly we shouldn't. + +0.1.1. Encoding integers + + Unless we explicitly say otherwise below, all numeric values in the + Tor protocol are encoded in network (big-endian) order. So a "32-bit + integer" means a big-endian 32-bit integer; a "2-byte" integer means + a big-endian 16-bit integer, and so forth. + 0.2. Security parameters Tor uses a stream cipher, a public-key cipher, the Diffie-Hellman @@ -1277,6 +1284,10 @@ see tor-design.pdf. The FLAGS value has one or more of the following bits set, where "bit 1" is the LSB of the 32-bit value, and "bit 32" is the MSB. + (Remember that all values in Tor are big-endian (see 0.1.1 above), so + the MSB of a 4-byte value is the MSB of the first byte, and the LSB + of a 4-byte value is the LSB of its last byte.) + bit meaning 1 -- IPv6 okay. We support learning about IPv6 addresses and connecting to IPv6 addresses.