# ECDSA verification of signature with foreign key **URL:** \ **Category:** ZYMKEY4\ **Created:** [July 3, 2020, 1:44pm UTC](https://community.zymbit.com/t/ecdsa-verification-of-signature-with-foreign-key/811 "2020-07-03T13:44:56Z")\ **Posts on this page:** 2\ **Page:** 1
**Author:** ![blackraven](https://avatars.discourse-cdn.com/v4/letter/b/b9e5f3/32.png) [@blackraven](https://community.zymbit.com/u/blackraven)\ **Post date:** [July 3, 2020, 1:44pm UTC](https://community.zymbit.com/t/ecdsa-verification-of-signature-with-foreign-key/811/1 "2020-07-03T13:44:56Z")
Hello, My application use-case requires to verify signatures over messages given an external (foreign) public key using the zymbit. I wonder if you could provide an example of verification of a signature using a foreign public key since the API documentation does not matches the current module.py implementation: def verify\_digest(self, sha256, sig, raise\_exception=True, pubkey\_slot=0, foreign=False): In the python API documentation PDF file: def zymkey.module.Zymkey.verify (self, src, sig, raise\_exception = True, slot = 0, pubkey = None, pubkey\_curve = ‘NISTP256’, sig\_is\_der = False ) However, I cannot find such declaration in the python API installed in my raspberry. Thanks in advance. ---
**Author:** ![Bob\_of\_Zymbit](https://avatars.discourse-cdn.com/v4/letter/b/82dd89/32.png) [@Bob\_of\_Zymbit](https://community.zymbit.com/u/Bob_of_Zymbit)\ **Post date:** [July 6, 2020, 4:07pm UTC](https://community.zymbit.com/t/ecdsa-verification-of-signature-with-foreign-key/811/2 "2020-07-06T16:07:49Z")
I apologize. I didn’t read your question correctly. I thought you were just pointing out the problem that the syntax in the API document doesn’t match the module. The zymkey APIs do not support the use of a foreign public key. You have to use a key from the zymkey. I’m editing my original post to reflect that.