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| author | Nick Mathewson <nickm@torproject.org> | 2023-02-06 21:00:24 +0000 |
|---|---|---|
| committer | Nick Mathewson <nickm@torproject.org> | 2023-02-06 21:00:24 +0000 |
| commit | e4596ecced32a08c0d9437722fe6354092e405ec (patch) | |
| tree | 4e4a3861a4fad9baf58787bb78fb0ddda2dd11f5 | |
| parent | 103c7720c0e6c16d2e964dfebc566f47053ef121 (diff) | |
| parent | 7b3d7a40a0ac8f59b9f6d79205dfc53de4168f0c (diff) | |
| download | torspec-e4596ecced32a08c0d9437722fe6354092e405ec.tar.gz torspec-e4596ecced32a08c0d9437722fe6354092e405ec.zip | |
Merge branch 'hs-desc-ephem' into 'main'
Call the key in desc-auth-ephemeral-key, KP_hs_desc_ephem
See merge request tpo/core/torspec!111
| -rw-r--r-- | rend-spec-v3.txt | 12 |
1 files changed, 4 insertions, 8 deletions
diff --git a/rend-spec-v3.txt b/rend-spec-v3.txt index a8ac264..805e0d9 100644 --- a/rend-spec-v3.txt +++ b/rend-spec-v3.txt @@ -1208,7 +1208,7 @@ Table of contents: If client authorization is disabled, the value here should be "x25519". - "desc-auth-ephemeral-key" SP key NL + "desc-auth-ephemeral-key" SP KP_hs_desc_ephem NL [Exactly once] @@ -1231,21 +1231,17 @@ Table of contents: When client authorization is enabled, each "auth-client" line contains the descriptor cookie encrypted to each individual client. We assume that - each authorized client possesses a pre-shared x25519 keypair which is - used to decrypt the descriptor cookie. + each authorized client possesses a pre-shared x25519 keypair + KS/KP_hsc_desc_enc which is used to decrypt the descriptor cookie. We now describe the descriptor cookie encryption scheme. Here are the relevant keys: - client_x = private x25519 key of authorized client - client_X = public x25519 key of authorized client - hs_y = private key of ephemeral x25519 keypair of hidden service - hs_Y = public key of ephemeral x25519 keypair of hidden service descriptor_cookie = descriptor cookie used to encrypt the descriptor And here is what the hidden service computes: - SECRET_SEED = x25519(hs_y, client_X) + SECRET_SEED = x25519(KS_hs_desc_ephem, KP_hsc_desc_enc) KEYS = KDF(N_hs_subcred | SECRET_SEED, 40) CLIENT-ID = fist 8 bytes of KEYS COOKIE-KEY = last 32 bytes of KEYS |