(Ruby) 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 Ruby Downloads install from rubygems.org gem install chilkat or download... Ruby Library for Windows, MacOS, Linux, Alpine Linux

require '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.new()
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 + "\n";

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

# (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.new()
success = privKey.LoadPemFile("qa_data/ecc/secp256r1-key-pkcs8.pem")
if (success != true)
    print privKey.lastErrorText() + "\n";
    exit
end

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

# Sign the hash..
ecdsa = Chilkat::CkEcc.new()
ecdsaSigBase64 = ecdsa.signHashENC(hash1,"base64",privKey,prng)
if (ecdsa.get_LastMethodSuccess() != true)
    print ecdsa.lastErrorText() + "\n";
    exit
end

print "ECDSA signature = " + ecdsaSigBase64 + "\n";

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

pubKey = Chilkat::CkPublicKey.new()
success = pubKey.LoadFromFile("qa_data/ecc/secp256r1-pubkey.pem")
if (success != true)
    print pubKey.lastErrorText() + "\n";
    exit
end

result = ecdsa.VerifyHashENC(hash1,ecdsaSigBase64,"base64",pubKey)
if (result == 1)
    print "Signature is valid." + "\n";
    exit
end

if (result == 0)
    print "Signature is invalid." + "\n";
    exit
end

if (result < 0)
    print ecdsa.lastErrorText() + "\n";
    print "The VerifyHashENC method call failed." + "\n";
    exit
end