(Ruby) RSA Sign with PKCS8 Encrypted Key

Demonstrates how to load a private key from an encrypted PKCS8 file and create an RSA digital signature (and then verify it).

Chilkat Ruby Downloads Ruby Library for Linux and MAC OS X

require 'chilkat'

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

pkey = Chilkat::CkPrivateKey.new()

# Load the private key from an RSA PEM file:
success = pkey.LoadPkcs8EncryptedFile("raul_privateKey.key","a0123456789")

# Get the private key in XML format:
pkeyXml = pkey.getXml()

rsa = Chilkat::CkRsa.new()

# Import the private key into the RSA component:
success = rsa.ImportPrivateKey(pkeyXml)
if (success != true)
    print rsa.lastErrorText() + "\n";
    exit
end

# This example will sign a string, and receive the signature
# in a hex-encoded string.  Therefore, set the encoding mode
# to "hex":
rsa.put_EncodingMode("hex")

strData = "This is the string to be signed."

# Sign the string using the sha-1 hash algorithm.
# Other valid choices are "md2" and "md5".
hexSig = rsa.signStringENC(strData,"sha-1")

print hexSig + "\n";

# Now verify with the public key.
# This example shows how to use the public key from 
# a digital certificate (.cer file)
cert = Chilkat::CkCert.new()
success = cert.LoadFromFile("raul_publicKey.cer")
if (success != true)
    print cert.lastErrorText() + "\n";
    exit
end

# pubKey is a CkPublicKey
pubKey = cert.ExportPublicKey()

# Get the private key in XML format:
pubKeyXml = pubKey.getXml()

rsa2 = Chilkat::CkRsa.new()
success = rsa2.ImportPublicKey(pubKeyXml)
if (success != true)
    print rsa2.lastErrorText() + "\n";
    exit
end

# Verify the signature against the original data:
rsa2.put_EncodingMode("hex")
success = rsa2.VerifyStringENC(strData,"sha-1",hexSig)
if (success != true)
    print rsa2.lastErrorText() + "\n";
    exit
end

print "Signature verified!" + "\n";

# Verify with incorrect data:
success = rsa2.VerifyStringENC("something else","sha-1",hexSig)
if (success != true)
    print "Signature not verified! (which was expected in this case)" + "\n";
else
    print "Hmmm... that's not right..." + "\n";
end