(CkPython) ECDSA Sign Data and Verify Signature

Demonstrates using the Elliptic Curve Digital Signature Algorithm to hash data and sign it. Also demonstrates how to verify the ECDSA signature.

Chilkat Python Downloads install with pip pip3 install chilkat or download... Python Module for Windows, MacOS, Linux, Alpine Linux, Solaris

import sys
import chilkat

# This example requires the Chilkat API to have been previously unlocked.
# See Global Unlock Sample for sample code.

# To create an ECDSA signature, the data first needs to be hashed.  Then the hash
# is signed.

# Use Chilkat Crypt2 to generate a hash for any of the following
# hash algorithms: SHA256, SHA384, SHA512, SHA1, MD5, MD2, HAVAL, RIPEMD128/160/256/320

crypt = chilkat.CkCrypt2()
crypt.put_HashAlgorithm("SHA256")
crypt.put_Charset("utf-8")
crypt.put_EncodingMode("base64")

# Hash a string.
hash1 = crypt.hashStringENC("The quick brown fox jumps over the lazy dog")
print("hash1 = " + hash1)

# Or hash a file..
hash2 = crypt.hashFileENC("qa_data/hamlet.xml")
print("hash2 = " + hash2)

# (The Crypt2 API provides many other ways to hash data..)

# -----------------------------------------------------------
# An ECDSA private key is used for signing.  The public key is for signature verification.
# Load our ECC private key.
# Our private key file contains this:

# 	// -----BEGIN PRIVATE KEY-----
# 	MIGHAgEAMBMGByqGSM49AgEGCCqGSM49AwEHBG0wawIBAQQg3J8q/24D1sEKGdP9
# 	72MGYElLGpw/a56Y3t6pfON3uhShRANCAATlSmoizyhAwoYZAOuFBATl07/1RR54
# 	a1Dzfm16grxJe666AGKR+bSs24hk7TEpaeCTvT8YOOM3l+xKFg7zq6Q9
# 	-----END PRIVATE KEY-----

privKey = chilkat.CkPrivateKey()
success = privKey.LoadPemFile("qa_data/ecc/secp256r1-key-pkcs8.pem")
if (success != True):
    print(privKey.lastErrorText())
    sys.exit()

# We'll need a PRNG source for random number generation.
# Use Chilkat's PRNG (for the Fortuna PRNG algorithm).
prng = chilkat.CkPrng()

# Sign the hash..
ecdsa = chilkat.CkEcc()
ecdsaSigBase64 = ecdsa.signHashENC(hash1,"base64",privKey,prng)
if (ecdsa.get_LastMethodSuccess() != True):
    print(ecdsa.lastErrorText())
    sys.exit()

print("ECDSA signature = " + ecdsaSigBase64)

# -----------------------------------------------------------
# Now let's verify the signature using the public key.

pubKey = chilkat.CkPublicKey()
success = pubKey.LoadFromFile("qa_data/ecc/secp256r1-pubkey.pem")
if (success != True):
    print(pubKey.lastErrorText())
    sys.exit()

result = ecdsa.VerifyHashENC(hash1,ecdsaSigBase64,"base64",pubKey)
if (result == 1):
    print("Signature is valid.")
    sys.exit()

if (result == 0):
    print("Signature is invalid.")
    sys.exit()

if (result < 0):
    print(ecdsa.lastErrorText())
    print("The VerifyHashENC method call failed.")
    sys.exit()