MIME S/MIME Encryption Algorithm Properties

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Demonstrates the properties that control S/MIME encryption: Pkcs7CryptAlg (the symmetric content-encryption algorithm), Pkcs7KeyLength (the content-encryption key length in bits), OaepPadding (whether RSAES-OAEP key transport is used instead of RSAES-PKCS1-v1_5), and the OAEP hash settings OaepHash and OaepMgfHash. The properties are configured before calling Encrypt.

import 'package:chilkat/chilkat.dart';

void main() {
  final mime = CkMime();
  try {
    mime.setBodyFromPlainText('This message will be encrypted.');
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // Pkcs7CryptAlg is the symmetric content-encryption algorithm.  Supported values are aes, aes-gcm,
  // des, 3des, and rc2.  The default is aes.
  mime.pkcs7CryptAlg = 'aes';

  // Pkcs7KeyLength is the content-encryption key length in bits.  The default is 128.
  mime.pkcs7KeyLength = 256;

  // OaepPadding selects the RSA key-transport padding.  The default is false (RSAES-PKCS1-v1_5).
  // Set true to use RSAES-OAEP, in which case the OAEP hash settings apply.
  mime.oaepPadding = true;
  mime.oaepHash = 'sha256';
  mime.oaepMgfHash = 'sha256';

  // Load the recipient certificate (public key is sufficient for encrypting).
  final cert = CkCert();
  try {
    cert.loadFromFile('qa_data/recipient.cer');
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // Encrypt using the algorithm settings configured above.
  try {
    mime.encrypt(cert);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  print('Encrypted with ${mime.pkcs7CryptAlg} ${mime.pkcs7KeyLength}-bit key.');
}