Perl

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. Perl

use chilkat();

$success = 0;

# 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 != 1) {
    print $cert->lastErrorText() . "\r\n";
    exit;
}

# 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 != 1) {
    print $privKey->lastErrorText() . "\r\n";
    exit;
}

# Set properties required for signing.

# Tell it to use the cert and private key we've loaded.
$success = $crypt->SetSigningCert2($cert,$privKey);
if ($success != 1) {
    print $crypt->lastErrorText() . "\r\n";
    exit;
}

# 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() != 1) {
    print $crypt->lastErrorText() . "\r\n";
    exit;
}

print $opaqueSig . "\r\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() != 1) {
    print $vCrypt->lastErrorText() . "\r\n";
    exit;
}

print "The extracted data: " . $extractedData . "\r\n";

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