Python PyCrypto: Sign Data Example.py

def sign_data(private_key_loc, data):
    '''
    param: private_key_loc Path to your private key
    param: package Data to be signed
    return: base64 encoded signature
    '''
    from Crypto.PublicKey import RSA 
    from Crypto.Signature import PKCS1_v1_5 
    from Crypto.Hash import SHA256 
    from base64 import b64encode, b64decode 
    key = open(private_key_loc, "r").read() 
    rsakey = RSA.importKey(key) 
    signer = PKCS1_v1_5.new(rsakey) 
    digest = SHA256.new() 
    # It's being assumed the data is base64 encoded, so it's decoded before updating the digest 
    digest.update(b64decode(data)) 
    sign = signer.sign(digest) 
    return b64encode(sign)