(.NET Core C#) JWE using ECDH-ES, BP-256, A256GCM

See more JSON Web Encryption (JWE) Examples

Create a JWE with the following header:

	{
	  "alg": "ECDH-ES",
	  "enc": "A256GCM",
	  "exp": 1621957030,
	  "cty": "NJWT",
	  "epk": {
	    "kty": "EC",
	    "x": "QLpJ_LpFx-6yJhsb4OvHwU1khLnviiOwYOvmf5clK7w"
	    "y": "AJh7pJ3zZKDJkm8rbeG69GBooTosXJgSsvNFH0i3Vxnu"
	    "crv": "BP-256"
	  }
	}

Note: This example requires Chilkat v9.5.0.87 or greater.

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

bool success;

// Load our brainpool BP-256 public key.

// 	{
// 	  "use": "enc",
// 	  "kid": "puk_idp_enc",
// 	  "kty": "EC",
// 	  "crv": "BP-256",
// 	  "x": "QLpJ_LpFx-6yJhsb4OvHwU1khLnviiOwYOvmf5clK7w",
// 	  "y": "AJh7pJ3zZKDJkm8rbeG69GBooTosXJgSsvNFH0i3Vxnu"
// 	}

Chilkat.JsonObject json = new Chilkat.JsonObject();
json.UpdateString("use","enc");
json.UpdateString("kid","puk_idp_enc");
json.UpdateString("kty","EC");
json.UpdateString("crv","BP-256");
json.UpdateString("x","QLpJ_LpFx-6yJhsb4OvHwU1khLnviiOwYOvmf5clK7w");
json.UpdateString("y","AJh7pJ3zZKDJkm8rbeG69GBooTosXJgSsvNFH0i3Vxnu");

Chilkat.PublicKey pubkey = new Chilkat.PublicKey();

success = pubkey.LoadFromString(json.Emit());
if (success == false) {
    Debug.WriteLine(pubkey.LastErrorText);
    return;
}

// Build our protected header:

// 	{
// 	  "alg": "ECDH-ES",
// 	  "enc": "A256GCM",
// 	  "exp": 1621957030,
// 	  "cty": "NJWT",
// 	  "epk": {
// 	    "kty": "EC",
// 	    "x": "QLpJ_LpFx-6yJhsb4OvHwU1khLnviiOwYOvmf5clK7w"
// 	    "y": "AJh7pJ3zZKDJkm8rbeG69GBooTosXJgSsvNFH0i3Vxnu"
// 	    "crv": "BP-256"
// 	  }
// 	}

// Use jwt only for getting the current date/time + 3600 seconds.
Chilkat.Jwt jwt = new Chilkat.Jwt();

Chilkat.JsonObject jweProtHdr = new Chilkat.JsonObject();
jweProtHdr.UpdateString("alg","ECDH-ES");
jweProtHdr.UpdateString("enc","A256GCM");
jweProtHdr.UpdateInt("exp",jwt.GenNumericDate(3600));
jweProtHdr.UpdateString("cty","NJWT");
jweProtHdr.UpdateString("epk.kty","EC");
jweProtHdr.UpdateString("epk.x","QLpJ_LpFx-6yJhsb4OvHwU1khLnviiOwYOvmf5clK7w");
jweProtHdr.UpdateString("epk.y","AJh7pJ3zZKDJkm8rbeG69GBooTosXJgSsvNFH0i3Vxnu");
jweProtHdr.UpdateString("epk.crv","BP-256");

Chilkat.Jwe jwe = new Chilkat.Jwe();
jwe.SetProtectedHeader(jweProtHdr);
jwe.SetPublicKey(0,pubkey);

string plainText = "This is the text to be encrypted.";
string strJwe = jwe.Encrypt(plainText,"utf-8");
if (jwe.LastMethodSuccess != true) {
    Debug.WriteLine(jwe.LastErrorText);
    return;
}

Debug.WriteLine(strJwe);

Debug.WriteLine("Success.");