commit 50b1937b2f59d29f5d31e8eadf9f991b821676e5 Author: George Kadianakis desnacked@riseup.net Date: Wed Apr 13 14:58:25 2016 +0300

prop224: Specify sane use of PRNG once and for all.

Tor is doing the right thing anyway, and specs would look terrible if we have to refer to [RANDOM-REFS] everytime we use random bytes. --- proposals/224-rend-spec-ng.txt | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/proposals/224-rend-spec-ng.txt b/proposals/224-rend-spec-ng.txt index a47be65..6526e05 100644 --- a/proposals/224-rend-spec-ng.txt +++ b/proposals/224-rend-spec-ng.txt @@ -97,6 +97,11 @@ Status: Draft

This specification uses the following cryptographic building blocks:

+ * A pseudorandom number generator backed by a strong entropy source. + The output of the PRNG should always be hashed before being posted on + the network to avoid leaking raw PRNG bytes to the network + (see [PRNG-REFS]). + * A stream cipher STREAM(iv, k) where iv is a nonce of length S_IV_LEN bytes and k is a key of length S_KEY_LEN bytes.

@@ -1487,9 +1492,7 @@ Status: Draft Pubkey [32 bytes] Signature [64 bytes]

- Nonce is a random value. (Noncen should be derived from hashed PRNG - output, so that we don't leak the raw bytes returned by a PRNG to the - network. See [RANDOM-REFS].) Pubkey is the public key that will be used + Nonce is a random value. Pubkey is the public key that will be used to authenticate. [TODO: should this be an identifier for the public key instead?] Signature is the signature, using Ed25519, of:

@@ -1532,9 +1535,7 @@ Status: Draft by the client. The client SHOULD choose a new rendezvous cookie for each new connection attempt. If the rendezvous cookie is already in use on an existing circuit, the rendezvous point should reject it and - destroy the circuit. RENDEZVOUS_COOKIE should be derived using hashed - PRNG output, so that we don't leak the raw bytes returned by a PRNG - to the network. See [RANDOM-REFS]. + destroy the circuit.

Upon receiving a ESTABLISH_RENDEZVOUS cell, the rendezvous point associates the cookie with the circuit on which it was sent. It @@ -1673,7 +1674,7 @@ References: J. Bernstein, Niels Duif, Tanja Lange, Peter Schwabe, and Bo-Yin Yang. http://cr.yp.to/papers.html#ed25519

-[RANDOM-REFS]: +[PRNG-REFS]: http://projectbullrun.org/dual-ec/ext-rand.html https://lists.torproject.org/pipermail/tor-dev/2015-November/009954.html