Skip to content

canonical versions of sigencode methods #17

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 1 commit into from
Feb 18, 2014
Merged

canonical versions of sigencode methods #17

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
18 changes: 18 additions & 0 deletions ecdsa/util.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -197,6 +197,24 @@ def sigencode_string(r, s, order):
def sigencode_der(r, s, order):
return der.encode_sequence(der.encode_integer(r), der.encode_integer(s))

# canonical versions of sigencode methods
# these enforce low S values, by negating the value (modulo the order) if above order/2
# see CECKey::Sign() https://github.com/bitcoin/bitcoin/blob/master/src/key.cpp#L214
def sigencode_strings_canonize(r, s, order):
if s > order / 2:
s = order - s
return sigencode_strings(r, s, order)

def sigencode_string_canonize(r, s, order):
if s > order / 2:
s = order - s
return sigencode_string(r, s, order)

def sigencode_der_canonize(r, s, order):
if s > order / 2:
s = order - s
return sigencode_der(r, s, order)


def sigdecode_string(signature, order):
l = orderlen(order)
Expand Down