(PHP Extension) Generate RSA Key and Sign a String

See more RSA Examples

Demonstrates how to generate a new RSA public/private key pair and use it to generate a signature for a string. The (binary) digital signature is returned as a hexidecimalized string.

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<?php

// The version number (9_5_0) should match version of the Chilkat extension used, omitting the micro-version number.
// For example, if using Chilkat v9.5.0.48, then include as shown here:
include("chilkat_9_5_0.php");

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

$rsa = new CkRsa();

// Generate a 2048-bit RSA key.
$success = $rsa->GenerateKey(2048);

// To return the signature in hex.
$rsa->put_EncodingMode('hex');

$strData = 'This is the string to be signed.';

// Sign the SHA256 hash of the string.
$hexSig = $rsa->signStringENC($strData,'sha256');

print $hexSig . "\n";
print $rsa->lastErrorText() . "\n";

// Now verify the signature:
$success = $rsa->VerifyStringENC($strData,'sha256',$hexSig);
if ($success == true) {
    print 'Signature verified!' . "\n";
}
else {
    print $rsa->lastErrorText() . "\n";
}

// Try it with an invalid signature:
$success = $rsa->VerifyStringENC($strData,'sha256','not a valid sig');
if ($success == true) {
    print 'Signature verified!' . "\n";
}
else {
    print $rsa->lastErrorText() . "\n";
}

// Try it with invalid data:
$success = $rsa->VerifyStringENC('Not the original data','sha256',$hexSig);
if ($success == true) {
    print 'Signature verified!' . "\n";
}
else {
    print $rsa->lastErrorText() . "\n";
}

// Try it with the wrong hash algorithm:
$success = $rsa->VerifyStringENC($strData,'sha-1',$hexSig);
if ($success == true) {
    print 'Signature verified!' . "\n";
}
else {
    print $rsa->lastErrorText() . "\n";
}


?>