Strict DER signature encoding/decoding.

Installation

pip install bip66

This library is a migration of https://github.com/bitcoinjs/bip66 to python

See bip66.

• This module works only with two's complement numbers.
• BIP66 doesn't check that r or s are fully valid.
  • check/decode doesn't check that r or s great than 33 bytes or that this number represent valid point on elliptic curve.
  • encode doesn't check that r/s represent valid point on elliptic curve.

Example

import binascii
import bip66
r = "29db2d5f4e1dcc04e19266cce3cb135865784c62ab653b307f0e0bb744f5c2aa"
s = "00a97f5826912cac8b44d9f577a26f169a2f8db781f2ddb7de2bc886e93b6844"
encoded = bip66.encode(binascii.unhexlify(r), binascii.unhexlify(s))
signature = binascii.hexlify(encoded).decode()
# > 3044022029db2d5f4e1dcc04e19266cce3cb135865784c62ab653b307f0e0bb744f5c2aa022000a97f5826912cac8b44d9f577a26f169a2f8db781f2ddb7de2bc886e93b6844

DER = "3044022029db2d5f4e1dcc04e19266cce3cb135865784c62ab653b307f0e0bb" \
      "744f5c2aa022000a97f5826912cac8b44d9f577a26f169a2f8db781f2ddb7de2bc886e93b6844"
r, s = bip66.decode(binascii.unhexlify(DER))
print(binascii.hexlify(r).decode())
print(binascii.hexlify(s).decode())

# > 29db2d5f4e1dcc04e19266cce3cb135865784c62ab653b307f0e0bb744f5c2aa
# > 00a97f5826912cac8b44d9f577a26f169a2f8db781f2ddb7de2bc886e93b6844

A catch-all exception regex:

/Expected DER (integer|sequence)|(R|S) value (excessively padded|is negative)|(R|S|DER sequence) length is (zero|too short|too long|invalid)/

LICENSE MIT