/// <summary>BouncyCastleでMacのハッシュ値を計算して返す。</summary>
/// <param name="data">データ（バイト配列）</param>
/// <param name="key">キー（バイト配列）</param>
/// <param name="mac">IMac</param>
/// <returns>ハッシュ値（バイト配列）</returns>
public static byte[] GetMacBytesByBC(byte[] data, byte[] key, IMac mac)
{
mac.Init(new KeyParameter(key));
mac.BlockUpdate(data, 0, data.Length);
byte[] rtnVal = new byte[mac.GetMacSize()];
mac.DoFinal(rtnVal, 0);
if (mac.AlgorithmName == "DESede/CBC" &&
8 < rtnVal.Length)
{
rtnVal = ArrayOperator.CopyArray <byte>(rtnVal, 8);
}
return(rtnVal);
// <HMAC>
// mac = new HMac(new RipeMD160Digest());
// <MACTripleDES>
// mac = new CbcBlockCipherMac(new DesEdeEngine(), 64));
// https://www.go4expert.com/articles/bouncy-castle-net-implementation-triple-t24829/
// ECBモードのDESEDEと、CBCモードのTriple DESがある。
// https://stackoverflow.com/questions/34660907/how-to-encrypt-decrypt-string-using-mactripledes
// MACTripleDESはCBC-MACを使用します。 CBC-MACは、メッセージにゼロを埋め込んだ後にCBCモードを使用します。
}
/// <summary>初期化（プロバイダ）</summary>
/// <param name="forEncrypt">bool</param>
private void InitAesCbc(bool forEncrypt)
{
// PaddedBufferedBlockCipher
this._aesCBC = new PaddedBufferedBlockCipher(
new CbcBlockCipher(new AesEngine()), new Pkcs7Padding());
// Initialization Vector.
// IV must be the same length as block size
this.IV = ArrayOperator.CopyArray <byte>(this.IV, this._aesCBC.GetBlockSize());
// 初期化
// EncKey length is 128 / 192 / 256 bits.
this._aesCBC.Reset();
this._aesCBC.Init(forEncrypt, new ParametersWithIV(
new KeyParameter(this.EncKey, 0, this.EncKey.Length), this.IV));
// MacKey
this._hmac.Initialize();
this._hmac.Key = this.MacKey;
}
/// <summary>constructor</summary>
/// <param name="cek">コンテンツ暗号化キー（CEK）</param>
/// <param name="iv">初期化ベクトル</param>
/// <param name="aad">追加認証データ（AAD）</param>
public AeadAesCbc(byte[] cek, byte[] iv, byte[] aad) : base(cek, iv, aad)
{
// 各種サイズの初期化
this.InitSize();
// CEK -> MacKey & EncKey
if (cek.Length < CEK_LEN)
{
throw new ArgumentException(string.Format("Length is less than {0} bytes.", this.CEK_LEN), "cek");
}
this.MacKey = ArrayOperator.CopyArray <byte>(cek, MAC_KEY_LEN);
this.EncKey = ArrayOperator.CopyArray <byte>(cek, ENC_KEY_LEN, ENC_KEY_LEN, 0);
// Initialization Vector.
this.IV = iv;
// Additional Authenticated Data
this.AAD = aad;
// HMac
this.AL = this.InitAL();
}
/// <summary>constructor</summary>
/// <param name="cek">コンテンツ暗号化キー（CEK）</param>
/// <param name="iv">初期化ベクトル</param>
/// <param name="aad">追加認証データ（AAD）</param>
public AeadAesGcm(byte[] cek, byte[] iv, byte[] aad) : base(cek, iv, aad)
{
// 各種サイズの初期化
this.InitSize();
if (cek.Length < CEK_LEN)
{
throw new ArgumentException("Length is less than 128 bits.", "cek");
}
else if (cek.Length == CEK_LEN)
{
this.Cek = cek;
}
else
{
this.Cek = ArrayOperator.CopyArray(cek, CEK_LEN);
}
// Use of an IV of size 96 bits is REQUIRED with this algorithm.
this._iv = iv;
// The requested size of the Authentication Tag output MUST be 128 bits, regardless of the key size.
this._aad = aad;
}
/// <summary>暗号化</summary>
/// <param name="plaint">平文（plaintext）</param>
/// <returns>AEAD実行結果オブジェクト</returns>
public override void Encrypt(byte[] plaint)
{
// AesGcm実装を初期化
this.InitAesGcm(true);
// GCM操作の実行
byte[] aead = new byte[this._aesGcm.GetOutputSize(plaint.Length)];
int len = this._aesGcm.ProcessBytes(plaint, 0, plaint.Length, aead, 0);
len += this._aesGcm.DoFinal(aead, len);
// GetMacで認証タグ（MAC）を取得
byte[] tag = this._aesGcm.GetMac();
// 結果を返す
this._result = new AeadResult()
{
Aead = aead, // aead = ciphert + tag
// <ciphertの抽出>
// plaint.Lengthと、ciphert.Length - tag.Length を使う方法がある。
Ciphert = ArrayOperator.CopyArray <byte>(aead, plaint.Length),
Tag = tag,
};
}
