次の暗号化方法があります。解読できません。暗号化アルゴリズムを継承しているため、変更できません。
public static string Encrypt(string plaintext)
{
byte[] rgbIV;
byte[] key;
RijndaelManaged rijndael = BuildRigndaelCommon(out rgbIV, out key);
//convert plaintext into a byte array
byte[] plaintextBytes = Encoding.UTF8.GetBytes(plaintext);
int BlockSize;
BlockSize = 16 * (1 + (plaintext.Length / 16));
Array.Resize(ref plaintextBytes, BlockSize);
// fill the remaining space with 0
for (int i = plaintext.Length; i < BlockSize; i++)
{
plaintextBytes[i] = 0;
}
byte[] cipherTextBytes = null;
//create uninitialized Rijndael encryption obj
using (RijndaelManaged symmetricKey = new RijndaelManaged())
{
//Call SymmetricAlgorithm.CreateEncryptor to create the Encryptor obj
var transform = rijndael.CreateEncryptor();
//Chaining mode
symmetricKey.Mode = CipherMode.CFB;
//create encryptor from the key and the IV value
ICryptoTransform encryptor = symmetricKey.CreateEncryptor(key, rgbIV);
//define memory stream to hold encrypted data
using (MemoryStream ms = new MemoryStream())
{
//define cryptographic stream - contains the transformation key to be used and the mode
using (CryptoStream cs = new CryptoStream(ms, encryptor, CryptoStreamMode.Write))
{
//encrypt contents of cryptostream
cs.Write(plaintextBytes, 0, BlockSize);
cs.FlushFinalBlock();
//convert encrypted data from a memory stream into a byte array
cipherTextBytes = ms.ToArray();
}
}
}
//store result as a hex value
string hexOutput = BitConverter.ToString(cipherTextBytes).Replace("-", "");
hexOutput = hexOutput.Substring(0, plaintext.Length * 2);
//finially return encrypted string
return hexOutput;
}
ご覧のとおり、最後に16進数に変換され、部分文字列が実行されることを除いて、かなり標準的です。私は反対のことをするのに非常に苦労しています。
私の復号化方法は次のようなものです：
public static string Decrypt(string disguisedtext)
{
byte[] rgbIV;
byte[] key;
BuildRigndaelCommon(out rgbIV, out key);
byte[] disguishedtextBytes = FromHexString(disguisedtext);
string visiabletext = "";
//create uninitialized Rijndael encryption obj
using (var symmetricKey = new RijndaelManaged())
{
//Call SymmetricAlgorithm.CreateEncryptor to create the Encryptor obj
symmetricKey.Mode = CipherMode.CFB;
//create encryptor from the key and the IV value
// ICryptoTransform encryptor = symmetricKey.CreateEncryptor(key, rgbIV);
ICryptoTransform decryptor = symmetricKey.CreateDecryptor(key, rgbIV);
//define memory stream to hold encrypted data
using (MemoryStream ms = new MemoryStream(disguishedtextBytes))
{
//define cryptographic stream - contains the transformation to be used and the mode
using (CryptoStream cs = new CryptoStream(ms, decryptor, CryptoStreamMode.Write))
{
byte[] plaintextBytes = new Byte[disguishedtextBytes.Length];
cs.Write(disguishedtextBytes, 0, disguishedtextBytes.Length);
cs.FlushFinalBlock();
//convert decrypted data from a memory stream into a byte array
byte[] visiabletextBytes = ms.ToArray();
visiabletext = Encoding.UTF8.GetString(visiabletextBytes);
}
}
}
return visiabletext;
}
ヘルパー メソッド:
private static RijndaelManaged BuildRigndaelCommon(out byte[] rgbIV, out byte[] key)
{
rgbIV = new byte[] { 0x0, 0x1, 0x2, 0x3, 0x5, 0x6, 0x7, 0x8, 0xA, 0xB, 0xC, 0xD, 0xF, 0x10, 0x11, 0x12 };
key = new byte[] { 0x0, 0x1, 0x2, 0x3, 0x5, 0x6, 0x7, 0x8, 0xA, 0xB, 0xC, 0xD, 0xF, 0x10, 0x11, 0x12 };
//Specify the algorithms key & IV
RijndaelManaged rijndael = new RijndaelManaged{BlockSize = 128, IV = rgbIV, KeySize = 128, Key = key, Padding = PaddingMode.None};
return rijndael;
}
public static byte[] FromHexString(string hexString)
{
if (hexString == null)
{
return new byte[0];
}
var numberChars = hexString.Length;
var bytes = new byte[numberChars / 2];
for (var i = 0; i < numberChars; i += 2)
{
bytes[i / 2] = Convert.ToByte(hexString.Substring(i, 2), 16);
}
return bytes;
}
文字列の長さに関するさまざまなエラーが発生し、パディングが無効です。復号化を機能させるためのアイデアはありますか。入力文字列を 32 バイトに戻そうとしましたが、役に立ちませんでした。