`from_public_key_recovery` function using wrong parameter

[kcorlidy]

pubkey = "fe27389aada80332ec2478814eb3c81de9d1109bc3c21d23853a43bd16ed176057371f3ce271d1ef423ef6fa56f97925a07036158bf90bb87c6c24f248932554"

msg = "3045022100c3c38c977a3c11214f76eb59616a69838dbc14fc0d666e16c0d65989f7f9245b022037861ec5d4599caf17d80da102a89616a545cfca1932253bc2a539a0c9cb66e8"
msg = bytes.fromhex(msg)
raw_msg = "9302bda273a887cb40c13e02a50b4071a31fd3aae3ae04021b0b843dd61ad18e"
raw_msg = bytes.fromhex(raw_msg)

# right data
_r = 0x00c3c38c977a3c11214f76eb59616a69838dbc14fc0d666e16c0d65989f7f9245b
_s = 0x37861ec5d4599caf17d80da102a89616a545cfca1932253bc2a539a0c9cb66e8
signature = msg
data = raw_msg
curve = ecdsa.curves.SECP256k1

print("correct", _r, _s)
generator = curve.generator
r, s = ecdsa.util.sigdecode_der(signature, generator.order())
print(r, s)

pubkey = ecdsa.VerifyingKey.from_public_key_recovery(
		signature=signature, data=data, curve=curve, sigdecode=ecdsa.util.sigdecode_der)
print(hexlify(pubkey[0].to_string()), hexlify(pubkey[1].to_string()))

Then i got error

correct 88546510979682037774707173221481493851486333744139811890585270440885638210651 25114176564622922097833533925221099216470038098832442934481636541806701930216

88546510979682037774707173221481493851486333744139811890585270440885638210651 25114176564622922097833533925221099216470038098832442934481636541806701930216
Traceback (most recent call last):
  File "C:\Users\hasee\Desktop\test2.py", line 85, in <module>
    signature=signature, data=data, curve=curve, sigdecode=ecdsa.util.sigdecode_der)
  File "D:\anaconda3\envs\py37\lib\site-packages\ecdsa\keys.py", line 89, in from_public_key_recovery
    return klass.from_public_key_recovery_with_digest(signature, digest, curve, hashfunc=sha1, sigdecode=sigdecode_string)
  File "D:\anaconda3\envs\py37\lib\site-packages\ecdsa\keys.py", line 97, in from_public_key_recovery_with_digest
    r, s = sigdecode(signature, generator.order())
  File "D:\anaconda3\envs\py37\lib\site-packages\ecdsa\util.py", line 238, in sigdecode_string
    assert len(signature) == 2 * l, (len(signature), 2 * l)
AssertionError: (71, 64)

So i view #102 and code, then found the reason
https://github.com/warner/python-ecdsa/blob/master/src/ecdsa/keys.py#L89
The code should be return klass.from_public_key_recovery_with_digest(signature, digest, curve, hashfunc=sha1, sigdecode=sigdecode)

After changing the code, i got the correct public key

correct is 88546510979682037774707173221481493851486333744139811890585270440885638210651 25114176564622922097833533925221099216470038098832442934481636541806701930216
88546510979682037774707173221481493851486333744139811890585270440885638210651 25114176564622922097833533925221099216470038098832442934481636541806701930216
b'fe27389aada80332ec2478814eb3c81de9d1109bc3c21d23853a43bd16ed176057371f3ce271d1ef423ef6fa56f97925a07036158bf90bb87c6c24f248932554' b'9eb524f1401c38df84374fa68047d5cbdabe5ac710406012fc162a588347e8856fa4850ef58394a91cb8c413ccf6b5e2fbc97755c1cbf833020e97e2cfec062a'

[tomato42]

sigdecode is the default signature decoding method, why do you think that the default is wrong? why it shouldn't be sigdecode_string?

[tomato42]

no, scratch that, I though that the issue was with default value of the parameter

yes, it's a bug