Skip to content

VerifyingKey.verify() with 71 bytes signature #269

Description

@Bastien-BO

Hello,

i'm curently trying to use python-ecdsa to verify message's integrity from gpay.
to do so google give a sig that is 71 bytes:

That folow this structure (i believe):
6 byte | DER encoding overhead
32 byte | r-value
32 byte | S-value
1 byte | Signature Hash

Exemple

pub: str = "BOdoXP+9Aq473SnGwg3JU1aiNpsd9vH2ognq4PtDtlLGa3Kj8TPf+jaQNPyDSkh3JUhiS0KyrrlWhAgNZKHYF2Y\u003d"
sig: str= "MEUCIQDY3SyBgKv2iegv4hOd3iYTPB43oLOMe4MMZN3QPv9XFAIgIfuT4Uzof6fIFe8lUucowAecPbwsod6DY8Q5JFaB7Q8\u003d"

vk2 = VerifyingKey.from_string(base64.b64decode(pub), curve=NIST256p, hashfunc=hashlib.sha256)
vk2.verify(signature=base64.b64decode(sig), data="my_data".encode(), hashfunc=hashlib.sha256)

the error message i get: "ecdsa.keys.BadSignatureError: ('Malformed formatting of signature', MalformedSignature('Invalid length of signature, expected 64 bytes long, provided string is 71 bytes long'))"

Is there a way to use this signature as is with the lib ? Or do i need to trim unnecessary bytes, if so do you have any advises ?

regards,

Activity

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

Metadata

Metadata

Assignees

No one assigned

    Labels

    Type

    No type

    Projects

    No projects

      Milestone

      No milestone

      Relationships

      None yet

      Development

      No branches or pull requests

      Issue actions