Ruby

Create and Verify an Opaque PKCS7/CMS Signature

See more Digital Signatures Examples

Demonstrates how to create a PKCS7 opaque signature, and also how to verify an opaque signature. An opaque signature is different than a detached PKCS7 signature in that it contains the original data. Verifying an opaque signature retrieves the original content. Ruby

require 'chilkat'

success = false

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

crypt = Chilkat::CkCrypt2.new()

# A certificate and private key is needed to create a signature.
# Chilkat provides many different ways to load a certificate and private key, such
# as from a PFX/.p12, Java keystore, JWK, Windows registry-based certificate stores, and other sources.
# This example will load the certificate from a .crt and the private key from a .key file

cert = Chilkat::CkCert.new()
# The LoadFromFile method will automatically detect the format and load it.
success = cert.LoadFromFile("qa_data/certs/test_12345678a.cer")
if (success != true)
    print cert.lastErrorText() + "\n";
    exit
end

# Our private key is in an encrypted PKCS8 format.
# If you don't know the format of your key, but you do know it's encrypted,
# and requires a password, then just call any of the Chilkat methods that load
# a private key w/ a password argument.  Chilkat will auto-detect the format
# and load it correctly even if it's not the format indicated by the method name..
privKey = Chilkat::CkPrivateKey.new()
password = "12345678a"
success = privKey.LoadPkcs8EncryptedFile("qa_data/certs/test_12345678a.key",password)
if (success != true)
    print privKey.lastErrorText() + "\n";
    exit
end

# Set properties required for signing.

# Tell it to use the cert and private key we've loaded.
success = crypt.SetSigningCert2(cert,privKey)
if (success != true)
    print crypt.lastErrorText() + "\n";
    exit
end

# Indicate we want the opaque signature in base64 format:
crypt.put_EncodingMode("base64")

# Sign the string using the "utf-8" byte representation:
crypt.put_Charset("utf-8")

# Create the opaque signature:
originalData = "This is the string to be signed."
opaqueSig = crypt.opaqueSignStringENC(originalData)
if (crypt.get_LastMethodSuccess() != true)
    print crypt.lastErrorText() + "\n";
    exit
end

print opaqueSig + "\n";

# The output looks like this:
# MIIPgQYJKoZIhvcNAQcCoIIPcjCCD24CAQExCzAJBgUrDgMCGgUAMC8GCSqGSIb3DQEHAaAiBCBUaGlzIGlzIHRoZSBzdHJpbmcgdG8gYmUgc...

# ----------------------------------------------------------------------------------------------
# Now let's verify the signature and retrieve the original data.
# We'll use a new Crypt2 object to keep things completely separate...

vCrypt = Chilkat::CkCrypt2.new()

vCrypt.put_EncodingMode("base64")
vCrypt.put_Charset("utf-8")

extractedData = vCrypt.opaqueVerifyStringENC(opaqueSig)
if (vCrypt.get_LastMethodSuccess() != true)
    print vCrypt.lastErrorText() + "\n";
    exit
end

print "The extracted data: " + extractedData + "\n";

# The output is:
# The extracted data: This is the string to be signed.