PHP Requires Chilkat v11.0.0+

JWE using RSAES-OAEP and AES GCM

See more JSON Web Encryption (JWE) Examples

This example duplicates the example A.1 in RFC 7516 for JSON Web Encryption (JWE). Chilkat2 PHP

<?php

use Chilkat2\JsonObject;
use Chilkat2\Jwe;
use Chilkat2\PrivateKey;
use Chilkat2\PublicKey;
use Chilkat2\StringBuilder;

// 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 = 'The true sign of intelligence is not knowledge but imagination.';

// ---------------------------------
// A.1.1 JOSE Header
// First build the JWE Protected Header.
// We want to build this: {"alg":"RSA-OAEP","enc":"A256GCM"}
$jweProtHdr = new JsonObject();
$jweProtHdr->AppendString('alg', 'RSA-OAEP');
$jweProtHdr->AppendString('enc', 'A256GCM');
echo 'JWE Protected Header: ', $jweProtHdr->Emit(), "\n";
echo "--\n";

// ---------------------------------
// A.1.2 Content Encryption Key
// Note: Chilkat automatically generates the random CEK internally.
// The application does not need to explicitly take this step.

// ---------------------------------
// A.1.3.  Key Encryption
// The application should load an RSA private key from any format.
// However, the application does not need to explicitly construct the JWE Encrypted Key.
// Chilkat automatically does it internally.
// The design of the Chilkat JWE API is to allow the application to create the JWE
// after specifying the inputs.  (This is in contrast to forcing the application developer
// to painstakingly go through each step of the JWE construction process.)

// The specific RSA key used in the A.1 example is the following JWK:
$sbJwk = new StringBuilder();
$sbJwk->Append('{"kty": "RSA",');
$sbJwk->Append('"n": "oahUIoWw0K0usKNuOR6H4wkf4oBUXHTxRvgb48E-BVvxkeDNjbC4he8rUW');
$sbJwk->Append('cJoZmds2h7M70imEVhRU5djINXtqllXI4DFqcI1DgjT9LewND8MW2Krf3S');
$sbJwk->Append('psk_ZkoFnilakGygTwpZ3uesH-PFABNIUYpOiN15dsQRkgr0vEhxN92i2a');
$sbJwk->Append('sbOenSZeyaxziK72UwxrrKoExv6kc5twXTq4h-QChLOln0_mtUZwfsRaMS');
$sbJwk->Append('tPs6mS6XrgxnxbWhojf663tuEQueGC-FCMfra36C9knDFGzKsNa7LZK2dj');
$sbJwk->Append('YgyD3JR_MB_4NUJW_TqOQtwHYbxevoJArm-L5StowjzGy-_bq6Gw",');
$sbJwk->Append('"e": "AQAB",');
$sbJwk->Append('"d": "kLdtIj6GbDks_ApCSTYQtelcNttlKiOyPzMrXHeI-yk1F7-kpDxY4-WY5N');
$sbJwk->Append('WV5KntaEeXS1j82E375xxhWMHXyvjYecPT9fpwR_M9gV8n9Hrh2anTpTD9');
$sbJwk->Append('3Dt62ypW3yDsJzBnTnrYu1iwWRgBKrEYY46qAZIrA2xAwnm2X7uGR1hghk');
$sbJwk->Append('qDp0Vqj3kbSCz1XyfCs6_LehBwtxHIyh8Ripy40p24moOAbgxVw3rxT_vl');
$sbJwk->Append('t3UVe4WO3JkJOzlpUf-KTVI2Ptgm-dARxTEtE-id-4OJr0h-K-VFs3VSnd');
$sbJwk->Append('VTIznSxfyrj8ILL6MG_Uv8YAu7VILSB3lOW085-4qE3DzgrTjgyQ",');
$sbJwk->Append('"p": "1r52Xk46c-LsfB5P442p7atdPUrxQSy4mti_tZI3Mgf2EuFVbUoDBvaRQ-');
$sbJwk->Append('SWxkbkmoEzL7JXroSBjSrK3YIQgYdMgyAEPTPjXv_hI2_1eTSPVZfzL0lf');
$sbJwk->Append('fNn03IXqWF5MDFuoUYE0hzb2vhrlN_rKrbfDIwUbTrjjgieRbwC6Cl0",');
$sbJwk->Append('"q": "wLb35x7hmQWZsWJmB_vle87ihgZ19S8lBEROLIsZG4ayZVe9Hi9gDVCOBm');
$sbJwk->Append('UDdaDYVTSNx_8Fyw1YYa9XGrGnDew00J28cRUoeBB_jKI1oma0Orv1T9aX');
$sbJwk->Append('IWxKwd4gvxFImOWr3QRL9KEBRzk2RatUBnmDZJTIAfwTs0g68UZHvtc",');
$sbJwk->Append('"dp": "ZK-YwE7diUh0qR1tR7w8WHtolDx3MZ_OTowiFvgfeQ3SiresXjm9gZ5KL');
$sbJwk->Append('hMXvo-uz-KUJWDxS5pFQ_M0evdo1dKiRTjVw_x4NyqyXPM5nULPkcpU827');
$sbJwk->Append('rnpZzAJKpdhWAgqrXGKAECQH0Xt4taznjnd_zVpAmZZq60WPMBMfKcuE",');
$sbJwk->Append('"dq": "Dq0gfgJ1DdFGXiLvQEZnuKEN0UUmsJBxkjydc3j4ZYdBiMRAy86x0vHCj');
$sbJwk->Append('ywcMlYYg4yoC4YZa9hNVcsjqA3FeiL19rk8g6Qn29Tt0cj8qqyFpz9vNDB');
$sbJwk->Append('UfCAiJVeESOjJDZPYHdHY8v1b-o-Z2X5tvLx-TCekf7oxyeKDUqKWjis",');
$sbJwk->Append('"qi": "VIMpMYbPf47dT1w_zDUXfPimsSegnMOA1zTaX7aGk_8urY6R8-ZW1FxU7');
$sbJwk->Append('AlWAyLWybqq6t16VFd7hQd0y6flUK4SlOydB61gwanOsXGOAOv82cHq0E3');
$sbJwk->Append('eL4HrtZkUuKvnPrMnsUUFlfUdybVzxyjz9JF_XyaY14ardLSjf4L_FNY"}');

// Load this JWK into a Chilkat private key object.
$rsaPrivKey = new PrivateKey();
try {
    $rsaPrivKey->LoadJwk($sbJwk->GetAsString());

    // 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 = new PublicKey();
    $rsaPrivKey->ToPublicKey($rsaPubKey);

    // ---------------------------------
    // A.1.4.  Initialization Vector
    // Chilkat automatically generates the necessary random IV internally.
    // The application does not need to do this explicitly.

    // ---------------------------------
    // A.1.5.  Additional Authenticated Data
    // The Additional Authenticated Data encryption parameter is
    // ASCII(BASE64URL(UTF8(JWE Protected Header))).
    // Again, Chilkat automatically takes care of this internally.
    // The application does not need to explicitly take this step.

    // ---------------------------------
    // A.1.6.  Content Encryption
    // Again... this step is handled by Chilkat internally.

    // ---------------------------------
    // A.1.7.  Complete Representation
    // The application need only call the Encrypt, EncryptSb, or EncryptBd method
    // return the fully assembled JWE.
    // The final representation in the Compact Serialization
    // is the string BASE64URL(UTF8(JWE Protected Header)) || '.' ||
    // BASE64URL(JWE Encrypted Key) || '.' || BASE64URL(JWE Initialization
    // Vector) || '.' || BASE64URL(JWE Ciphertext) || '.' || BASE64URL(JWE
    // Authentication Tag).

    $jwe = new Jwe();
    $jwe->SetProtectedHeader($jweProtHdr);
    $jwe->SetPublicKey(0, $rsaPubKey);

    $strJwe = $jwe->Encrypt($plaintext, 'utf-8');
} catch (\Chilkat2\Exception $e) {
    echo $e->getMessage(), "\n";
    exit;
}

// Note: The RSA OAEP algorithm uses random padding bytes internally.
// Therefore, the results will appear different each time -- even if the
// identical plaintext is encrypted with the identical RSA key.
// (Do not expect the appearance of the results to be the same as what
// is published in the RFC.  However, what is published in the RFC *should*
// be decryptable using the code that follows.)
echo $strJwe, "\n";

// 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 Jwe();
try {
    $jwe2->LoadJwe($strJwe);

    // 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');
} catch (\Chilkat2\Exception $e) {
    echo $e->getMessage(), "\n";
    exit;
}

echo "original text: \n";
echo $originalPlaintext, "\n";

// ---------------------------------------------------------------------------------
// It should also be possible to decrypt the JWE as shown in RFC 7516, Appendix A.1.7
// because it was produced using the same RSA key.

$sbJwe = new StringBuilder();
$sbJwe->Append('eyJhbGciOiJSU0EtT0FFUCIsImVuYyI6IkEyNTZHQ00ifQ.');
$sbJwe->Append('OKOawDo13gRp2ojaHV7LFpZcgV7T6DVZKTyKOMTYUmKoTCVJRgckCL9kiMT03JGe');
$sbJwe->Append('ipsEdY3mx_etLbbWSrFr05kLzcSr4qKAq7YN7e9jwQRb23nfa6c9d-StnImGyFDb');
$sbJwe->Append('Sv04uVuxIp5Zms1gNxKKK2Da14B8S4rzVRltdYwam_lDp5XnZAYpQdb76FdIKLaV');
$sbJwe->Append('mqgfwX7XWRxv2322i-vDxRfqNzo_tETKzpVLzfiwQyeyPGLBIO56YJ7eObdv0je8');
$sbJwe->Append('1860ppamavo35UgoRdbYaBcoh9QcfylQr66oc6vFWXRcZ_ZT2LawVCWTIy3brGPi');
$sbJwe->Append('6UklfCpIMfIjf7iGdXKHzg.');
$sbJwe->Append('48V1_ALb6US04U3b.');
$sbJwe->Append('5eym8TW_c8SuK0ltJ3rpYIzOeDQz7TALvtu6UG9oMo4vpzs9tX_EFShS8iB7j6ji');
$sbJwe->Append('SdiwkIr3ajwQzaBtQD_A.');
$sbJwe->Append('XFBoMYUZodetZdvTiFvSkQ');

try {
    $jwe2->LoadJweSb($sbJwe);

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

    // Decrypt.
    $originalPlaintext = $jwe2->Decrypt(0, 'utf-8');
} catch (\Chilkat2\Exception $e) {
    echo $e->getMessage(), "\n";
    exit;
}

echo $originalPlaintext, "\n";