[tor-commits] [torspec/master] rend-spec-v3: document trailing zero byte in BLIND_STRING (A.2.)

[nickm at torproject.org]

commit 73f26437470e4b4b360a484daaa1ce94efad317f
Author: Filippo Valsorda <hi at filippo.io>
Date:   Fri Nov 17 15:18:57 2017 -0500

    rend-spec-v3: document trailing zero byte in BLIND_STRING (A.2.)
    
    The implementation uses sizeof instead of strlen, so the C string NUL byte is hashed.
---
 rend-spec-v3.txt | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/rend-spec-v3.txt b/rend-spec-v3.txt
index ef5f940..d595268 100644
--- a/rend-spec-v3.txt
+++ b/rend-spec-v3.txt
@@ -2160,7 +2160,7 @@ A.2. Tor's key derivation scheme
   blinding factor like this:
 
            h = H(BLIND_STRING | A | s | B | N)
-           BLIND_STRING = "Derive temporary signing key"
+           BLIND_STRING = "Derive temporary signing key" | INT_1(0)
            N = "key-blind" | INT_8(period-number) | INT_8(period_length)
 
   then clamp the blinding factor 'h' according to the ed25519 spec: