decryptJWE function

Future<String> decryptJWE(String jweCompact, Map<String, dynamic> key)

Decrypts the provided jweCompact using the specified key. Returns the decrypted payload as a string.

Implementation

Future<String> decryptJWE(String jweCompact, Map<String, dynamic> key) async {
  var split = jweCompact.split(".");
  if (split[0].length % 4 != 0) {
    var paddingLength = 4 - (split[0].length % 4);
    split[0] += "=" * paddingLength;
  }

  String jsonString = utf8.decode(base64Url.decode(split[0]));
  var jsonObject = json.decode(jsonString);
  if (jsonObject["alg"] == "ECDH-ES") {
    jsonObject["alg"] = "dir";
    split[0] = base64Url.encode(utf8.encode(json.encode(jsonObject)));
  }
  var jweString = split.join(".");

  var keyJwk = JsonWebKey.fromJson(key);
  var jwe = JsonWebEncryption.fromCompactSerialization(jweString);
  var keyStore = JsonWebKeyStore()..addKey(keyJwk);
  var payload = await jwe.getPayload(keyStore);

  return payload.stringContent;
}