(PHP Extension) JWE using RSAES-PKCS1-v1_5 and AES_128_CBC_HMAC_SHA_256

This example duplicates the example A.2 in RFC 7516 for JSON Web Encryption (JWE).

Note: This example requires Chilkat v9.5.0.66 or greater.

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

// Note: This example requires Chilkat v9.5.0.66 or greater.

$plaintext = 'Live long and prosper.';

// First build the JWE Protected Header.
// We want to build this: {"alg":"RSA1_5","enc":"A128CBC-HS256"}
$jweProtHdr = new CkJsonObject();
$jweProtHdr->AppendString('alg','RSA1_5');
$jweProtHdr->AppendString('enc','A128CBC-HS256');
print 'JWE Protected Header: ' . $jweProtHdr->emit() . "\n";
print '--' . "\n";

// The specific RSA key used in the A.2 example is the following JWK:
$sbJwk = new CkStringBuilder();
$sbJwk->Append('{\'kty\':\'RSA\',');
$sbJwk->Append('\'n\':\'sXchDaQebHnPiGvyDOAT4saGEUetSyo9MKLOoWFsueri23bOdgWp4Dy1Wl');
$sbJwk->Append('UzewbgBHod5pcM9H95GQRV3JDXboIRROSBigeC5yjU1hGzHHyXss8UDpre');
$sbJwk->Append('cbAYxknTcQkhslANGRUZmdTOQ5qTRsLAt6BTYuyvVRdhS8exSZEy_c4gs_');
$sbJwk->Append('7svlJJQ4H9_NxsiIoLwAEk7-Q3UXERGYw_75IDrGA84-lA_-Ct4eTlXHBI');
$sbJwk->Append('Y2EaV7t7LjJaynVJCpkv4LKjTTAumiGUIuQhrNhZLuF_RJLqHpM2kgWFLU');
$sbJwk->Append('7-VTdL1VbC2tejvcI2BlMkEpk1BzBZI0KQB0GaDWFLN-aEAw3vRw\',');
$sbJwk->Append('\'e\':\'AQAB\',');
$sbJwk->Append('\'d\':\'VFCWOqXr8nvZNyaaJLXdnNPXZKRaWCjkU5Q2egQQpTBMwhprMzWzpR8Sxq');
$sbJwk->Append('1OPThh_J6MUD8Z35wky9b8eEO0pwNS8xlh1lOFRRBoNqDIKVOku0aZb-ry');
$sbJwk->Append('nq8cxjDTLZQ6Fz7jSjR1Klop-YKaUHc9GsEofQqYruPhzSA-QgajZGPbE_');
$sbJwk->Append('0ZaVDJHfyd7UUBUKunFMScbflYAAOYJqVIVwaYR5zWEEceUjNnTNo_CVSj');
$sbJwk->Append('-VvXLO5VZfCUAVLgW4dpf1SrtZjSt34YLsRarSb127reG_DUwg9Ch-Kyvj');
$sbJwk->Append('T1SkHgUWRVGcyly7uvVGRSDwsXypdrNinPA4jlhoNdizK2zF2CWQ\',');
$sbJwk->Append('\'p\':\'9gY2w6I6S6L0juEKsbeDAwpd9WMfgqFoeA9vEyEUuk4kLwBKcoe1x4HG68');
$sbJwk->Append('ik918hdDSE9vDQSccA3xXHOAFOPJ8R9EeIAbTi1VwBYnbTp87X-xcPWlEP');
$sbJwk->Append('krdoUKW60tgs1aNd_Nnc9LEVVPMS390zbFxt8TN_biaBgelNgbC95sM\',');
$sbJwk->Append('\'q\':\'uKlCKvKv_ZJMVcdIs5vVSU_6cPtYI1ljWytExV_skstvRSNi9r66jdd9-y');
$sbJwk->Append('BhVfuG4shsp2j7rGnIio901RBeHo6TPKWVVykPu1iYhQXw1jIABfw-MVsN');
$sbJwk->Append('-3bQ76WLdt2SDxsHs7q7zPyUyHXmps7ycZ5c72wGkUwNOjYelmkiNS0\',');
$sbJwk->Append('\'dp\':\'w0kZbV63cVRvVX6yk3C8cMxo2qCM4Y8nsq1lmMSYhG4EcL6FWbX5h9yuv');
$sbJwk->Append('ngs4iLEFk6eALoUS4vIWEwcL4txw9LsWH_zKI-hwoReoP77cOdSL4AVcra');
$sbJwk->Append('Hawlkpyd2TWjE5evgbhWtOxnZee3cXJBkAi64Ik6jZxbvk-RR3pEhnCs\',');
$sbJwk->Append('\'dq\':\'o_8V14SezckO6CNLKs_btPdFiO9_kC1DsuUTd2LAfIIVeMZ7jn1Gus_Ff');
$sbJwk->Append('7B7IVx3p5KuBGOVF8L-qifLb6nQnLysgHDh132NDioZkhH7mI7hPG-PYE_');
$sbJwk->Append('odApKdnqECHWw0J-F0JWnUd6D2B_1TvF9mXA2Qx-iGYn8OVV1Bsmp6qU\',');
$sbJwk->Append('\'qi\':\'eNho5yRBEBxhGBtQRww9QirZsB66TrfFReG_CcteI1aCneT0ELGhYlRlC');
$sbJwk->Append('tUkTRclIfuEPmNsNDPbLoLqqCVznFbvdB7x-Tl-m0l_eFTj2KiqwGqE9PZ');
$sbJwk->Append('B9nNTwMVvH3VRRSLWACvPnSiwP8N5Usy-WRXS-V7TbpxIhvepTfE0NNo\'');
$sbJwk->Append('}');

// Load this JWK into a Chilkat private key object.
$rsaPrivKey = new CkPrivateKey();
$success = $rsaPrivKey->LoadJwk($sbJwk->getAsString());
if ($success != true) {
    print $rsaPrivKey->lastErrorText() . "\n";
    exit;
}

// The public key is used to encrypt (i.e. create the JWE), 
// and the private key is used to decrypt.
// The RSA public key is simply a subset of the private key.  The RSA public key
// is composed of the "n" and "e" members shown above.  These are also known as the
// modulus and exponent.
// We can simply get the public key object from the private key object
// rsaPubKey is a CkPublicKey
$rsaPubKey = $rsaPrivKey->GetPublicKey();

// Create the JWE...
$jwe = new CkJwe();
$jwe->SetProtectedHeader($jweProtHdr);
$jwe->SetPublicKey(0,$rsaPubKey);

$strJwe = $jwe->encrypt($plaintext,'utf-8');
if ($jwe->get_LastMethodSuccess() != true) {
    print $jwe->lastErrorText() . "\n";
    exit;
}

// Show the JWE we just created:
print $strJwe . "\n";

// Note: The RSA PKCS1_V1_5 padding uses random value, and the results
// will be different each time.  However, each result should be successfully
// decrypting if using the correct RSA private key.

// Let's decrypt the JWE that was just produced.
// Do the following to decrypt a JWE:
// 1) Load the JWE.
// 2) Set the private key for decryption.
// 3) Decrypt.
$jwe2 = new CkJwe();
$success = $jwe2->LoadJwe($strJwe);
if ($success != true) {
    print $jwe2->lastErrorText() . "\n";
    exit;
}

// Provide the RSA private key for decryption.
// (The JWE was encrypted for a single recipient at index 0.)
$jwe2->SetPrivateKey(0,$rsaPrivKey);

// Decrypt.
$originalPlaintext = $jwe2->decrypt(0,'utf-8');
if ($jwe2->get_LastMethodSuccess() != true) {
    print $jwe2->lastErrorText() . "\n";
    exit;
}

print 'original text: ' . "\n";
print $originalPlaintext . "\n";

// ---------------------------------------------------------------------------------
// It should also be possible to decrypt the JWE as shown in RFC 7516, Appendix A.2.7
// because it was produced using the same RSA key.

$sbJwe = new CkStringBuilder();
$sbJwe->Append('eyJhbGciOiJSU0ExXzUiLCJlbmMiOiJBMTI4Q0JDLUhTMjU2In0.');
$sbJwe->Append('UGhIOguC7IuEvf_NPVaXsGMoLOmwvc1GyqlIKOK1nN94nHPoltGRhWhw7Zx0-kFm');
$sbJwe->Append('1NJn8LE9XShH59_i8J0PH5ZZyNfGy2xGdULU7sHNF6Gp2vPLgNZ__deLKxGHZ7Pc');
$sbJwe->Append('HALUzoOegEI-8E66jX2E4zyJKx-YxzZIItRzC5hlRirb6Y5Cl_p-ko3YvkkysZIF');
$sbJwe->Append('NPccxRU7qve1WYPxqbb2Yw8kZqa2rMWI5ng8OtvzlV7elprCbuPhcCdZ6XDP0_F8');
$sbJwe->Append('rkXds2vE4X-ncOIM8hAYHHi29NX0mcKiRaD0-D-ljQTP-cFPgwCp6X-nZZd9OHBv');
$sbJwe->Append('-B3oWh2TbqmScqXMR4gp_A.');
$sbJwe->Append('AxY8DCtDaGlsbGljb3RoZQ.');
$sbJwe->Append('KDlTtXchhZTGufMYmOYGS4HffxPSUrfmqCHXaI9wOGY.');
$sbJwe->Append('9hH0vgRfYgPnAHOd8stkvw');

$success = $jwe2->LoadJweSb($sbJwe);
if ($success != true) {
    print $jwe2->lastErrorText() . "\n";
    exit;
}

// Provide the RSA private key for decryption.
$jwe2->SetPrivateKey(0,$rsaPrivKey);

// Decrypt.
$originalPlaintext = $jwe2->decrypt(0,'utf-8');
if ($jwe2->get_LastMethodSuccess() != true) {
    print $jwe2->lastErrorText() . "\n";
    exit;
}

print $originalPlaintext . "\n";

?>