gistfile1.py

import requests
from M2Crypto import BIO, RSA, EVP, X509

def verify_message(pem, msg, sig):
    cert = X509.load_cert_string(pem)
    pubkey = cert.get_pubkey()
    sig = sig.decode('base64')

    # Write a few files to disk for debugging purposes
    f = open("sig", "wb")
    f.write(sig)
    f.close()

    f = open("msg", "w")
    f.write(msg)
    f.close()

    f = open("mypubkey.pem", "w")
    f.write(pubkey.get_rsa().as_pem())
    f.close()

    pubkey.reset_context(md='sha1')
    pubkey.verify_init()
    pubkey.verify_update(msg)
    return pubkey.verify_final(sig)

PEM = """-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----
"""

MSG = """

"""

SIG = """
FFOSR4UhPjheKN3hNAXIh/XL5OByp23+Gk+NRgonsZoI0eQHJn7nCEr/b1NbL/DP7UVL7o
nM6+RC1/yjiSi4J8wj4kqs19PY4ZGQXbnnDxutJoMfo+lhRA/H+jTPL5u8bs/d07ln0eHl
AzyOCxee3DRTxJKbmQewb48xhmou4jQ=
"""

print verify_message(PEM, PEM, SIG)