WIP

Signed-off-by: Nguyen Van Nguyen <[email protected]>

lib/src/common/argon2_s2k.dart

@@ -13,7 +13,7 @@ import 'helpers.dart';
 
 /// Implementation of the Argon2 string-to-key specifier
 /// See https://www.rfc-editor.org/rfc/rfc9580#section-3.7
-class Argon2S2k implements S2kInterface {
+final class Argon2S2k implements S2kInterface {
   /// Default salt length
   static const saltLength = 16;
 

lib/src/common/armor.dart

@@ -17,7 +17,7 @@ import 'helpers.dart';
 /// encoding of the binary data and a checksum.
 /// See https://www.rfc-editor.org/rfc/rfc9580#section-6
 /// Author Nguyen Van Nguyen <[email protected]>
-class Armor {
+final class Armor {
   static const version = 'Dart PG v2';
   static const comment = 'The Dart OpenPGP library';
 

lib/src/common/generic_s2k.dart

@@ -14,7 +14,7 @@ import 'helpers.dart';
 
 /// Implementation of the string-to-key specifier
 /// See https://www.rfc-editor.org/rfc/rfc9580#section-3.7
-class GenericS2k implements S2kInterface {
+final class GenericS2k implements S2kInterface {
   /// Default salt length
   static const saltLength = 8;
 

lib/src/cryptor/aead/eax.dart

@@ -13,7 +13,7 @@ import '../../type/aead.dart';
 
 /// EAX Authenticated-Encryption class
 /// Author Nguyen Van Nguyen <[email protected]>
-class Eax implements AeadInterface {
+final class Eax implements AeadInterface {
   final Uint8List key;
   final SymmetricAlgorithm symmetric;
 

lib/src/cryptor/aead/gcm.dart

@@ -13,7 +13,7 @@ import '../../type/aead.dart';
 
 /// GCM Authenticated-Encryption class
 /// Author Nguyen Van Nguyen <[email protected]>
-class Gcm implements AeadInterface {
+final class Gcm implements AeadInterface {
   final Uint8List key;
   final SymmetricAlgorithm symmetric;
 

lib/src/cryptor/aead/ocb.dart

@@ -13,7 +13,7 @@ import '../../type/aead.dart';
 
 /// OCB Authenticated-Encryption class
 /// Author Nguyen Van Nguyen <[email protected]>
-class Ocb implements AeadInterface {
+final class Ocb implements AeadInterface {
   final Uint8List key;
   final SymmetricAlgorithm symmetric;
 
@@ -81,7 +81,7 @@ class Ocb implements AeadInterface {
 /// An implementation of RFC 7253 on The OCB Authenticated-Encryption Algorithm.
 /// See https://tools.ietf.org/html/rfc7253
 /// Author Nguyen Van Nguyen <[email protected]>
-class OCBCipher implements AEADCipher {
+final class OCBCipher implements AEADCipher {
   static const _blockSize = 16;
 
   final BlockCipher _hashCipher;

lib/src/cryptor/asymmetric/dsa.dart

@@ -12,7 +12,7 @@ import '../../common/helpers.dart';
 
 /// Implementation of DSA (digital signature algorithm)
 /// Author Nguyen Van Nguyen <[email protected]>
-class DSASigner implements Signer {
+final class DSASigner implements Signer {
   final Digest? _digest;
 
   late DSAAsymmetricKey? _key;
@@ -150,7 +150,7 @@ class DSASigner implements Signer {
   }
 }
 
-class DSASignature implements Signature {
+final class DSASignature implements Signature {
   final BigInt r;
   final BigInt s;
 
@@ -191,14 +191,14 @@ abstract class DSAAsymmetricKey implements AsymmetricKey {
   DSAAsymmetricKey(this.prime, this.order, this.generator);
 }
 
-class DSAPublicKey extends DSAAsymmetricKey implements PublicKey {
+final class DSAPublicKey extends DSAAsymmetricKey implements PublicKey {
   /// public exponent y = g ** x mod p
   final BigInt y;
 
   DSAPublicKey(this.y, super.prime, super.order, super.generator);
 }
 
-class DSAPrivateKey extends DSAAsymmetricKey implements PrivateKey {
+final class DSAPrivateKey extends DSAAsymmetricKey implements PrivateKey {
   /// secret exponent
   final BigInt x;
 

lib/src/cryptor/asymmetric/elgamal.dart

@@ -11,7 +11,7 @@ import '../../common/helpers.dart';
 
 /// Asymmetric block cipher using basic ElGamal algorithm.
 /// Author Nguyen Van Nguyen <[email protected]>
-class ElGamalEngine implements AsymmetricBlockCipher {
+final class ElGamalEngine implements AsymmetricBlockCipher {
   late ElGamalAsymmetricKey? _key;
 
   late SecureRandom _random;
@@ -149,14 +149,15 @@ abstract class ElGamalAsymmetricKey implements AsymmetricKey {
   ElGamalAsymmetricKey(this.prime, this.generator);
 }
 
-class ElGamalPublicKey extends ElGamalAsymmetricKey implements PublicKey {
+final class ElGamalPublicKey extends ElGamalAsymmetricKey implements PublicKey {
   /// public exponent y = g ** x mod p
   final BigInt y;
 
   ElGamalPublicKey(this.y, super.prime, super.generator);
 }
 
-class ElGamalPrivateKey extends ElGamalAsymmetricKey implements PrivateKey {
+final class ElGamalPrivateKey extends ElGamalAsymmetricKey
+    implements PrivateKey {
   /// secret exponent
   final BigInt x;
 

lib/src/cryptor/symmetric/blowfish.dart

@@ -15,7 +15,7 @@ import 'base_engine.dart';
 /// All the algorithms herein are from Applied Cryptography
 /// and implement a simplified cryptography interface.
 /// Author Nguyen Van Nguyen <[email protected]>
-class BlowfishEngine extends BaseEngine {
+final class BlowfishEngine extends BaseEngine {
   static const _kp = [
     0x243f6a88, 0x85a308d3, 0x13198a2e, 0x03707344, // 0 - 3
     0xa4093822, 0x299f31d0, 0x082efa98, 0xec4e6c89,

lib/src/cryptor/symmetric/buffered_cipher.dart

@@ -10,7 +10,7 @@ import 'package:pointycastle/api.dart';
 
 /// Buffered cipher.
 /// Author Nguyen Van Nguyen <[email protected]>
-class BufferedCipher {
+final class BufferedCipher {
   final BlockCipher _underlyingCipher;
 
   final Uint8List _buffer;

lib/src/cryptor/symmetric/camellia.dart

@@ -12,7 +12,7 @@ import '../../common/extensions.dart';
 
 /// Camellia - based on RFC 3713.
 /// Author Nguyen Van Nguyen <[email protected]>
-class CamelliaEngine extends BaseEngine {
+final class CamelliaEngine extends BaseEngine {
   static const _blockSize = 16;
 
   static const _mask8 = 0xff;

lib/src/cryptor/symmetric/cast5.dart

@@ -18,7 +18,7 @@ import '../../common/extensions.dart';
 ///
 /// and implement a simplified cryptography interface.
 /// Author Nguyen Van Nguyen <[email protected]>
-class CAST5Engine extends BaseEngine {
+final class CAST5Engine extends BaseEngine {
   static const _sBox1 = [
     0x30fb40d4, 0x9fa0ff0b, 0x6beccd2f, 0x3f258c7a, 0x1e213f2f, 0x9c004dd3,
     0x6003e540, 0xcf9fc949, // 0 - 7

lib/src/cryptor/symmetric/idea.dart

@@ -12,7 +12,7 @@ import '../../common/extensions.dart';
 
 /// A class that provides a basic International Data Encryption Algorithm (IDEA) engine.
 /// Author Nguyen Van Nguyen <[email protected]>
-class IDEAEngine extends BaseEngine {
+final class IDEAEngine extends BaseEngine {
   static const _mask = 0xffff;
   static const _base = 0x10001;
 

lib/src/cryptor/symmetric/twofish.dart

@@ -12,7 +12,7 @@ import '../../common/extensions.dart';
 
 /// A class that provides Twofish encryption operations.
 /// Author Nguyen Van Nguyen <[email protected]>
-class TwofishEngine extends BaseEngine {
+final class TwofishEngine extends BaseEngine {
   /// Q-Table 0
   static const _q0 = [
     0xa9, 0x67, 0xb3, 0xe8, 0x04, 0xfd, 0xa3, 0x76, // 0 - 7

lib/src/key/private_key.dart

@@ -19,6 +19,8 @@ import '../type/private_key.dart';
 import '../type/secret_key_packet.dart';
 import 'base_key.dart';
 
+/// OpenPGP private key class
+/// Author Nguyen Van Nguyen <[email protected]>
 final class PrivateKey extends BaseKey implements PrivateKeyInterface {
   PrivateKey(super.packetList);
 

lib/src/message/verification.dart

@@ -11,7 +11,7 @@ import '../type/verification.dart';
 
 /// Verification class
 /// Author Nguyen Van Nguyen <[email protected]>
-class Verification implements VerificationInterface {
+final class Verification implements VerificationInterface {
   @override
   final Uint8List keyID;
 

lib/src/packet/aead_encrypted_data.dart

@@ -16,7 +16,7 @@ import 'base_packet.dart';
 /// Implementation of the Symmetrically Encrypted Authenticated Encryption with
 /// Additional Data (AEAD) Protected Data Packet - Type 20
 /// Author Nguyen Van Nguyen <[email protected]>
-class AeadEncryptedDataPacket extends BasePacket
+final class AeadEncryptedDataPacket extends BasePacket
     implements EncryptedDataPacketInterface {
   static const version = 1;
 

lib/src/packet/compressed_data.dart

@@ -13,7 +13,7 @@ import 'base_packet.dart';
 
 /// Implementation of the Compressed Data (COMP) Packet - Type 11
 /// Author Nguyen Van Nguyen <[email protected]>
-class CompressedDataPacket extends BasePacket {
+final class CompressedDataPacket extends BasePacket {
   /// Default zip/zlib compression level, between 1 and 9
   static const deflateLevel = 6;
 

lib/src/packet/image_user_attribute.dart

@@ -10,7 +10,7 @@ import 'user_attribute_subpacket.dart';
 
 /// Implementation of the Image User Attribute Subpacket
 /// Author Nguyen Van Nguyen <[email protected]>
-class ImageUserAttribute extends UserAttributeSubpacket {
+final class ImageUserAttribute extends UserAttributeSubpacket {
   static const jpeg = 1;
 
   ImageUserAttribute(

lib/src/packet/key/aes_key_wrapper.dart

@@ -10,7 +10,7 @@ import 'key_wrapper.dart';
 
 /// An implementation of the AES Key Wrapper from the NIST Key Wrap Specification.
 /// Author Nguyen Van Nguyen <[email protected]>
-class AesKeyWrapper extends KeyWrapper {
+final class AesKeyWrapper extends KeyWrapper {
   AesKeyWrapper(final int keySize)
       : super(
           BlockCipher('AES/ECB'),

lib/src/packet/key/camellia_key_wrapper.dart

@@ -11,7 +11,7 @@ import 'key_wrapper.dart';
 
 /// An implementation of the Camellia key wrapper based on RFC 3657/RFC 3394.
 /// Author Nguyen Van Nguyen <[email protected]>
-class CamelliaKeyWrapper extends KeyWrapper {
+final class CamelliaKeyWrapper extends KeyWrapper {
   CamelliaKeyWrapper(final int keySize)
       : super(
           ECBBlockCipher(CamelliaEngine()),

lib/src/packet/key/dsa_public_material.dart

@@ -15,7 +15,7 @@ import '../../type/verification_key_material.dart';
 
 /// DSA public key material
 /// Author Nguyen Van Nguyen <[email protected]>
-class DSAPublicMaterial implements VerificationKeyMaterial {
+final class DSAPublicMaterial implements VerificationKeyMaterial {
   /// DSA prime p
   final BigInt prime;
 

lib/src/packet/key/dsa_secret_material.dart

@@ -15,7 +15,7 @@ import 'dsa_public_material.dart';
 
 /// DSA secret key material
 /// Author Nguyen Van Nguyen <[email protected]>
-class DSASecretMaterial implements SigningKeyMaterialInterface {
+final class DSASecretMaterial implements SigningKeyMaterialInterface {
   /// DSA secret exponent x
   final BigInt exponent;
 

lib/src/packet/key/ecdh_public_material.dart

@@ -14,7 +14,7 @@ import 'ec_public_material.dart';
 
 /// ECDH public key material
 /// Author Nguyen Van Nguyen <[email protected]>
-class ECDHPublicMaterial extends ECPublicMaterial {
+final class ECDHPublicMaterial extends ECPublicMaterial {
   final int reserved;
 
   /// Hash algorithm used with the KDF

lib/src/packet/key/ecdh_secret_material.dart

@@ -17,7 +17,7 @@ import 'ecdh_public_material.dart';
 
 /// ECDH secret key material
 /// Author Nguyen Van Nguyen <[email protected]>
-class ECDHSecretMaterial extends ECSecretMaterial
+final class ECDHSecretMaterial extends ECSecretMaterial
     implements SecretKeyMaterialInterface {
   @override
   final ECDHPublicMaterial publicMaterial;

lib/src/packet/key/ecdh_session_key_cryptor.dart

@@ -23,7 +23,7 @@ import 'session_key_cryptor.dart';
 
 /// ECDH session key cryptor class
 /// Author Nguyen Van Nguyen <[email protected]>
-class ECDHSessionKeyCryptor extends SessionKeyCryptor {
+final class ECDHSessionKeyCryptor extends SessionKeyCryptor {
   /// 20 octets representing the UTF-8 encoding of the string 'Anonymous Sender    '
   static const _anonymousSender = [
     0x41, 0x6e, 0x6f, 0x6e, // 0 - 3

lib/src/packet/key/ecdsa_public_material.dart

@@ -14,7 +14,7 @@ import '../../type/verification_key_material.dart';
 
 /// ECDSA public key material
 /// Author Nguyen Van Nguyen <[email protected]>
-class ECDSAPublicMaterial extends ECPublicMaterial
+final class ECDSAPublicMaterial extends ECPublicMaterial
     implements VerificationKeyMaterial {
   ECDSAPublicMaterial(super.oid, super.q);
 

lib/src/packet/key/ecdsa_secret_material.dart

@@ -16,7 +16,7 @@ import 'ecdsa_public_material.dart';
 
 /// ECDSA secret key material
 /// Author Nguyen Van Nguyen <[email protected]>
-class ECDSASecretMaterial extends ECSecretMaterial
+final class ECDSASecretMaterial extends ECSecretMaterial
     implements SigningKeyMaterialInterface {
   @override
   final ECDSAPublicMaterial publicMaterial;

lib/src/packet/key/eddsa_legacy_public_material.dart

@@ -14,7 +14,7 @@ import 'ec_public_material.dart';
 
 /// EdDSA legacy public key material
 /// Author Nguyen Van Nguyen <[email protected]>
-class EdDSALegacyPublicMaterial extends ECPublicMaterial
+final class EdDSALegacyPublicMaterial extends ECPublicMaterial
     implements VerificationKeyMaterial {
   EdDSALegacyPublicMaterial(super.oid, super.q);
 

lib/src/packet/key/eddsa_legacy_secret_material.dart

@@ -17,7 +17,7 @@ import 'eddsa_legacy_public_material.dart';
 
 /// EdDSA legacy secret key material
 /// Author Nguyen Van Nguyen <[email protected]>
-class EdDSALegacySecretMaterial implements SigningKeyMaterialInterface {
+final class EdDSALegacySecretMaterial implements SigningKeyMaterialInterface {
   /// Ed's seed parameter
   final BigInt seed;
 

lib/src/packet/key/eddsa_public_material.dart

@@ -16,7 +16,7 @@ import '../../type/verification_key_material.dart';
 
 /// EdDSA public key material
 /// Author Nguyen Van Nguyen <[email protected]>
-class EdDSAPublicMaterial implements VerificationKeyMaterial {
+final class EdDSAPublicMaterial implements VerificationKeyMaterial {
   final Uint8List publicKey;
 
   final EdDSACurve curve;

lib/src/packet/key/eddsa_secret_material.dart

@@ -16,7 +16,7 @@ import 'eddsa_public_material.dart';
 
 /// EdDSA secret key material
 /// Author Nguyen Van Nguyen <[email protected]>
-class EdDSASecretMaterial implements SigningKeyMaterialInterface {
+final class EdDSASecretMaterial implements SigningKeyMaterialInterface {
   final Uint8List secretKey;
 
   @override

lib/src/packet/key/elgamal_public_material.dart

@@ -12,7 +12,7 @@ import '../../type/key_material.dart';
 
 /// ElGamal public key material
 /// Author Nguyen Van Nguyen <[email protected]>
-class ElGamalPublicMaterial implements KeyMaterialInterface {
+final class ElGamalPublicMaterial implements KeyMaterialInterface {
   /// Elgamal prime p
   final BigInt prime;
 

lib/src/packet/key/elgamal_secret_material.dart

@@ -11,7 +11,9 @@ import '../../cryptor/asymmetric/elgamal.dart';
 import '../../type/secret_key_material.dart';
 import 'elgamal_public_material.dart';
 
-class ElGamalSecretMaterial implements SecretKeyMaterialInterface {
+/// ElGamal secret key material
+/// Author Nguyen Van Nguyen <[email protected]>
+final class ElGamalSecretMaterial implements SecretKeyMaterialInterface {
   /// Elgamal secret exponent x.
   final BigInt exponent;
 

lib/src/packet/key/elgamal_session_key_cryptor.dart

@@ -15,7 +15,7 @@ import 'session_key_cryptor.dart';
 
 /// ElGamal session key cryptor class
 /// Author Nguyen Van Nguyen <[email protected]>
-class ElGamalSessionKeyCryptor extends SessionKeyCryptor {
+final class ElGamalSessionKeyCryptor extends SessionKeyCryptor {
   /// MPI of ElGamal (Diffie-Hellman) value g**k mod p.
   final BigInt gamma;
 

lib/src/packet/key/montgomery_public_material.dart

@@ -11,7 +11,7 @@ import '../../enum/montgomery_curve.dart';
 
 /// Montgomery public key material
 /// Author Nguyen Van Nguyen <[email protected]>
-class MontgomeryPublicMaterial implements KeyMaterialInterface {
+final class MontgomeryPublicMaterial implements KeyMaterialInterface {
   final Uint8List publicKey;
 
   final MontgomeryCurve curve;

lib/src/packet/key/montgomery_secret_material.dart

@@ -15,7 +15,7 @@ import 'montgomery_public_material.dart';
 
 /// Montgomery secret key material
 /// Author Nguyen Van Nguyen <[email protected]>
-class MontgomerySecretMaterial implements SecretKeyMaterialInterface {
+final class MontgomerySecretMaterial implements SecretKeyMaterialInterface {
   final Uint8List secretKey;
 
   @override

lib/src/packet/key/montgomery_session_key_cryptor.dart

@@ -14,7 +14,9 @@ import 'montgomery_public_material.dart';
 import 'montgomery_secret_material.dart';
 import 'session_key_cryptor.dart';
 
-class MontgomerySessionKeyCryptor extends SessionKeyCryptor {
+/// Montgomery session key cryptor
+/// Author Nguyen Van Nguyen <[email protected]>
+final class MontgomerySessionKeyCryptor extends SessionKeyCryptor {
   /// The ephemeral key used to establish the shared secret
   final Uint8List ephemeralKey;