arno/trezor-firmware
1
0
Fork 0
mirror of https://github.com/trezor/trezor-firmware.git synced 2025-02-23 04:52:01 +00:00
Code Issues Releases Wiki Activity

cosi: fix bug in signing code, make tests pass

Browse Source
This commit is contained in:
matejcik 2018-10-02 16:09:12 +02:00
parent 4ff5fb4492
commit a66cf99b74
1 changed files with 4 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
trezorlib/cosi.py
View File

@ -94,12 +94,13 @@ def sign_with_privkey(
""" """
b = _ed25519.b b = _ed25519.b
h = _ed25519.H(privkey) h = _ed25519.H(privkey)
a = int.from_bytes(h, "little")
# curvepoint preparation: # curvepoint preparation:
# 1. clear lowest three and highest bit # 1. take lowest b bits of h
a = int.from_bytes(h[: b // 8], "little")
# 2. clear lowest three and highest bit
bitmask = 1 + 2 + 4 + (1 << b - 1) bitmask = 1 + 2 + 4 + (1 << b - 1)
a &= ~bitmask a &= ~bitmask
# 2. set next-highest bit # 3. set next-highest bit
a |= 1 << b - 2 a |= 1 << b - 2
S = (nonce + _ed25519.Hint(global_commit + global_pubkey + digest) * a) % _ed25519.l S = (nonce + _ed25519.Hint(global_commit + global_pubkey + digest) * a) % _ed25519.l