(C# UWP/WinRT) JWE using A256GCMKW

This example demonstrates creating a JCE with AES GCM key wrap.

Chilkat Universal Windows Platform (UWP) / WinRT Downloads Chilkat for the Universal Windows Platform (UWP)

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

bool success;
string plaintext = "My text to enrypt";

Chilkat.Jwe jwe = new Chilkat.Jwe();

// First build the JWE Protected Header: 

//         {
//             "alg": "A256GCMKW",
//             "kid": "18ec08e1-bfa9-4d95-b205-2b4dd1d4321d",
//             "tag": "kfPduVQ3T3H6vnewt--ksw",
//             "iv": "KkYT0GX_2jHlfqN_",
//             "enc": "A128CBC-HS256"
//         }

Chilkat.JsonObject jweProtHdr = new Chilkat.JsonObject();
jweProtHdr.AppendString("alg","A256GCMKW");
// kid is optional
jweProtHdr.AppendString("kid","18ec08e1-bfa9-4d95-b205-2b4dd1d4321d");
// tag is optional
jweProtHdr.AppendString("tag","kfPduVQ3T3H6vnewt--ksw");
jweProtHdr.AppendString("enc","A256GCM");
// the iv should be 16 random chars.
Chilkat.Prng prng = new Chilkat.Prng();
jweProtHdr.AppendString("iv",prng.RandomString(16,true,true,true));
jwe.SetProtectedHeader(jweProtHdr);

Debug.WriteLine("JWE Protected Header: " + jweProtHdr.Emit());
Debug.WriteLine("--");

// Given that we have 256-bit AES, our key should be 32 bytes.
// The ascii string here is 32 bytes, therefore the 2nd arg is "ascii" to use these
// ascii chars directly as the key.
string aesWrappingKey = "2baf4f730f5e4542b428593ef9cceb0e";
jwe.SetWrappingKey(0,aesWrappingKey,"ascii");

// Encrypt and return the JWE:
string strJwe = jwe.Encrypt(plaintext,"utf-8");
if (jwe.LastMethodSuccess != true) {
    Debug.WriteLine(jwe.LastErrorText);
    return;
}

// Show the JWE we just created:
Debug.WriteLine(strJwe);

// Decrypt the JWE that was just produced.
// 1) Load the JWE.
// 2) Set the AES wrapping key.
// 3) Decrypt.
Chilkat.Jwe jwe2 = new Chilkat.Jwe();
success = jwe2.LoadJwe(strJwe);
if (success != true) {
    Debug.WriteLine(jwe2.LastErrorText);
    return;
}

// Set the AES wrap key.  Important to use "ascii"
jwe2.SetWrappingKey(0,aesWrappingKey,"ascii");

// Decrypt.
string originalPlaintext = jwe2.Decrypt(0,"utf-8");
if (jwe2.LastMethodSuccess != true) {
    Debug.WriteLine(jwe2.LastErrorText);
    return;
}

Debug.WriteLine("original text: ");
Debug.WriteLine(originalPlaintext);