Set a Per-Recipient JWE Header

See more JSON Web Encryption (JWE) Examples

Demonstrates Jwe.SetRecipientHeader, which sets the per-recipient unprotected header for a recipient index.

import 'package:chilkat/chilkat.dart';

void main() {
  final jwe = CkJwe();

  // Protected header: AES key-wrap with AES-256-GCM content encryption.
  final header = CkJsonObject();
  header.updateString('alg', 'A256KW');
  header.updateString('enc', 'A256GCM');
  try {
    jwe.setProtectedHeader(header);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // The 256-bit key-wrapping key (base64) for recipient index 0.  In production, obtain the key from a
  // secure source rather than hard-coding it.
  final base64Key = 'YWJjZGVmZ2hpamtsbW5vcHFyc3R1dnd4eXowMTIzNDU=';
  try {
    jwe.setWrappingKey(0, base64Key, 'base64');
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // Set the per-recipient unprotected header for recipient 0, for example a key id used to identify
  // which key a recipient should use.
  final recipHeader = CkJsonObject();
  recipHeader.updateString('kid', 'recipient-key-1');
  try {
    jwe.setRecipientHeader(0, recipHeader);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  final sbContent = CkStringBuilder();
  sbContent.append('This is the secret content.');
  final sbJwe = CkStringBuilder();
  try {
    jwe.encryptSb(sbContent, 'utf-8', sbJwe);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  print(sbJwe.getAsString());
}