Perl

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. Perl

use chilkat();

$success = 0;

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

$sb = chilkat::CkStringBuilder->new();
$crlfLineEnding = 1;

for ($i = 0; $i <= 10; $i++) {
    $sb->AppendLine("This is a test.",$crlfLineEnding);
}

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

# Get the public key to be used for signature verification.
$pubKey = chilkat::CkPublicKey->new();
$success = $pubKey->LoadFromFile("rsaKeys/chilkat-rsa-2048.pem");
if ($success == 0) {
    print $pubKey->lastErrorText() . "\r\n";
    exit;
}

$rsa = chilkat::CkRsa->new();
$success = $rsa->UsePublicKey($pubKey);
if ($success == 0) {
    print $rsa->lastErrorText() . "\r\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->put_Charset("utf-8");
$rsa->put_EncodingMode("base64");
$signedString = $sb->getAsString();
$success = $rsa->VerifyStringENC($signedString,"sha256",$base64_rsa_sig);

if ($success == 0) {
    print $rsa->lastErrorText() . "\r\n";
    print "Signature invalid." . "\r\n";
}
else {
    print "Signature valid." . "\r\n";
}