Create PKCS7 Signature using .cer and .key Files

Uses a digital certificate (.cer file) and private key file to create a PKCS7 signature.

Downloads for Windows/Linux and Install Instructions

require 'rubygems'
require 'chilkat'

#  First, load the .cer and .key files into Chilkat objects...
cert = Chilkat::CkCert.new()

success = cert.LoadFromFile("myCert.cer")
if (success != true)
    print cert.lastErrorText() + "\n";
    exit
end

privKey = Chilkat::CkPrivateKey.new()
password = "myPassword"
#  The private key object provides different methods for
#  loading keys of many different formats.
#  This example loads a PKCS8 encrypted private key.
success = privKey.LoadPkcs8EncryptedFile("myPrivateKey.key",password)
if (success != true)
    print privKey.lastErrorText() + "\n";
    exit
end

#  NOTE:  In this example, the .cer should contain the public key
#  that corresponds to the private key.

crypt = Chilkat::CkCrypt2.new()

#  Any string argument automatically begins the 30-day trial.
success = crypt.UnlockComponent("30-day trial")
if (success != true)
    print crypt.lastErrorText() + "\n";
    exit
end

#  Set the certifcate + private key to be used for signing:
crypt.SetSigningCert2(cert,privKey)

pkcs7 = Chilkat::CkByteData.new()

textToSign = "This is the text to be signed."
success = crypt.SignString(textToSign,pkcs7)
if (success == false)
    print crypt.lastErrorText() + "\n";
    exit
end

#  Save the PKCS7 signature to a file.
success = pkcs7.saveFile("out_pkcs7.p7s")
if (success == false)
    print "Failed to save output file." + "\n"
else
    print "Success." + "\n"
end