Python PyCrypto: Verify Signature Example.py

def verify_sign(public_key_loc, signature, data):
    '''
    Verifies with a public key from whom the data came that it was indeed 
    signed by their private key
    param: public_key_loc Path to public key
    param: signature String signature to be verified
    return: Boolean. True if the signature is valid; False otherwise. 
    '''
    from Crypto.PublicKey import RSA 
    from Crypto.Signature import PKCS1_v1_5 
    from Crypto.Hash import SHA256 
    from base64 import b64decode 
    pub_key = open(public_key_loc, "r").read() 
    rsakey = RSA.importKey(pub_key) 
    signer = PKCS1_v1_5.new(rsakey) 
    digest = SHA256.new() 
    # Assumes the data is base64 encoded to begin with
    digest.update(b64decode(data)) 
    if signer.verify(digest, b64decode(signature)):
        return True
    return False