Coverage for /pythoncovmergedfiles/medio/medio/usr/local/lib/python3.11/site-packages/starkbank_ecdsa-2.3.1-py3.11.egg/ellipticcurve/ecdsa.py: 89%

1from hashlib import sha256 

2from .signature import Signature 

3from .math import Math 

4from .utils.integer import RandomInteger 

5from .utils.binary import numberFromByteString 

6from .utils.compatibility import * 

7 

8 

9class Ecdsa: 

10 

11 @classmethod 

12 def sign(cls, message, privateKey, hashfunc=sha256): 

13 curve = privateKey.curve 

14 byteMessage = hashfunc(toBytes(message)).digest() 

15 numberMessage = numberFromByteString(byteMessage, curve.nBitLength) 

16 

17 r, s, randSignPoint = 0, 0, None 

18 kIterator = RandomInteger.rfc6979(byteMessage, privateKey.secret, curve, hashfunc) 

19 while r == 0 or s == 0: 

20 randNum = next(kIterator) 

21 randSignPoint = Math.multiplyGenerator(curve, randNum) 

22 r = randSignPoint.x % curve.N 

23 s = ((numberMessage + r * privateKey.secret) * (Math.inv(randNum, curve.N))) % curve.N 

24 recoveryId = randSignPoint.y & 1 

25 if randSignPoint.x >= curve.N: 

26 recoveryId += 2 

27 if s > curve.N // 2: 

28 s = curve.N - s 

29 recoveryId ^= 1 

30 

31 return Signature(r=r, s=s, recoveryId=recoveryId) 

32 

33 @classmethod 

34 def verify(cls, message, signature, publicKey, hashfunc=sha256): 

35 curve = publicKey.curve 

36 byteMessage = hashfunc(toBytes(message)).digest() 

37 numberMessage = numberFromByteString(byteMessage, curve.nBitLength) 

38 r = signature.r 

39 s = signature.s 

40 

41 if not 1 <= r <= curve.N - 1: 

42 return False 

43 if not 1 <= s <= curve.N - 1: 

44 return False 

45 if not curve.contains(publicKey.point): 

46 return False 

47 inv = Math.inv(s, curve.N) 

48 v = Math.multiplyAndAdd( 

49 curve.G, (numberMessage * inv) % curve.N, 

50 publicKey.point, (r * inv) % curve.N, 

51 curve=curve, 

52 ) 

53 if v.isAtInfinity(): 

54 return False 

55 return v.x % curve.N == r