Perl Requires Chilkat v11.0.0+

Verify an RSA Signature Against the Signed String

See more Apple Keychain Examples

Demonstrates how to validate an RSA Signature against the string that was signed. Chilkat2 Perl

use strict;
use warnings;
use Chilkat2;

# Create the same string we previously signed in this example:
# RSA Sign utf-8 Bytes of String to get Base64 RSA Signature

my $sb = Chilkat2::StringBuilder->new;
my $crlfLineEnding = 1;
for my $i (0 .. 10) {
    $sb->AppendLine('This is a test.', $crlfLineEnding);
}

my $base64_rsa_sig = 'gWgpEXQqvXN6wh0MuFXPiw2xCb8cnmdizBT1TD1Tpm2GlJ8gnD59DGSj35GGXk1tM+mCOvMa2uW/9gmz8p6A90JLbn918i/2wKGvcde4wXnzPO7JADSNn2UwYzf3rp4/q/JrHv1GZETRJhABSFqTxOgdmdbEJQE/zijOSctCtQAM2CTb6t2BO8uHKSSUAwPH2cbeWxqsaVRLT4ruk5nZOxhoLgLMSjupiSzbE8zSTkkFOEHD+Mbb2xwg85AI0E4DsUnp+hLwwtS0blesgSyvtBY8oJODJeFcJsR7JDOTPdzHQHgJRl/2A4ij5xT91TpXy7ok43jhT6O9j7Q3qrafIQ==';

# Get the public key to be used for signature verification.
my $pubKey = Chilkat2::PublicKey->new;
my $success = $pubKey->LoadFromFile('rsaKeys/chilkat-rsa-2048.pem');
if (!$success) {
    print $pubKey->LastErrorText, "\n";
    exit;
}

my $rsa = Chilkat2::Rsa->new;
$success = $rsa->UsePublicKey($pubKey);
if (!$success) {
    print $rsa->LastErrorText, "\n";
    exit;
}

# Verify the string against the signature.
# We signed the utf-8 byte representation of the string, so we must indicate
# to also validate against the utf-8 byte representation.
$rsa->Charset('utf-8');
$rsa->EncodingMode('base64');
my $signedString = $sb->GetAsString();
$success = $rsa->VerifyStringENC($signedString, 'sha256', $base64_rsa_sig);

if (!$success) {
    print $rsa->LastErrorText, "\n";
    print "Signature invalid.\n";
} else {
    print "Signature valid.\n";
}