我在我的代码中实现了3DES（TripleDES）解密例程，并注意到当提供的密文与前一次迭代相同时，它永远不会产生相同的明文。这似乎是不确定的，我确信这是我做错了。
我已经尝试过CBC（带有清零的IV），ECB，多种处置和清算组合。我似乎无法获得一致的输出。
（出于某种原因，下面“代码”和“输出”的代码格式不正确，抱歉）
代码
using System;
using System.Security.Cryptography;
using System.Threading;
namespace Test
{
class Program
{
static void Main(string[] args)
{
while (true)
{
string key = "27F66D5244FF621EAA6F6120EDEB427F";
string cipher = "C25C1D1197D31CAA87285D59A892047426D9182EC11353C051ADD6D0F072A6CB3436560B3071FC1FD11D9F7E74886742D9BEE0CFD1EA1064C213BB55278B2F12";
Console.WriteLine("clear: " + byte_array_to_hex_string(
decrypt_3des(
hex_string_to_byte_array(cipher),
hex_string_to_byte_array(key)
), true, true
));
Console.WriteLine("");
Thread.Sleep(1000);
}
}
static byte[] decrypt_3des(byte[] cipher, byte[] key)
{
if (cipher == null) return null;
if (key == null) return null;
int num_chunks = (cipher.Length) / 8;
Console.WriteLine("Entering decrypt_3des");
Console.WriteLine(" - cipher: " + byte_array_to_hex_string(cipher, true, true));
Console.WriteLine(" - key: " + byte_array_to_hex_string(key, true, true));
Console.WriteLine(" - cipher length: " + cipher.Length);
Console.WriteLine(" - key length: " + key.Length);
if ((cipher.Length % 8) != 0)
{
Console.WriteLine("cipher length not divisble by eight");
return null;
}
if ((key.Length % 8) != 0)
{
Console.WriteLine("key length not divisible by eight");
return null;
}
TripleDESCryptoServiceProvider tdes = new TripleDESCryptoServiceProvider();
tdes.Key = key;
tdes.Mode = CipherMode.ECB;
tdes.IV = new byte[] { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
tdes.Padding = PaddingMode.Zeros;
tdes.KeySize = (key.Length * 8);
ICryptoTransform ct = tdes.CreateDecryptor();
Console.WriteLine(" - IV: " + byte_array_to_hex_string(tdes.IV, true, true));
byte[] clear = new byte[(cipher.Length)];
clear = ct.TransformFinalBlock(cipher, 0, cipher.Length);
Console.WriteLine(" - clear: " + byte_array_to_hex_string(clear, true, true));
tdes.Clear();
tdes.Dispose();
ct.Dispose();
return clear;
}
public static byte[] hex_string_to_byte_array(string hex)
{
int number_chars = hex.Length;
byte[] bytes = new byte[number_chars / 2];
for (int i = 0; i < number_chars; i += 2)
{
bytes[i / 2] = Convert.ToByte(hex.Substring(i, 2), 16);
}
return bytes;
}
public static string byte_array_to_hex_string(byte[] ba, bool remove_dashes, bool include_spaces)
{
string hex = BitConverter.ToString(ba);
string hex_dashes = "";
string hex_spaces = "";
if (remove_dashes)
{
hex_dashes = hex.Replace("-", "");
}
else
{
return hex;
}
int hex_char_count = 0;
if (include_spaces)
{
for (int i = (hex_dashes.Length - 1); i >= 0; i--)
{
if (hex_char_count == 0)
{
hex_spaces += hex_dashes[i];
hex_char_count++;
continue;
}
if (hex_char_count % 16 == 0)
{
hex_spaces = (hex_dashes[i] + " " + hex_spaces);
hex_char_count++;
continue;
}
hex_spaces = hex_dashes[i] + hex_spaces;
hex_char_count++;
}
return hex_spaces;
}
else
{
return hex_dashes;
}
}
}
}
输出
Entering decrypt_3des - cipher: C25C1D1197D31CAA 87285D59A8920474 26D9182EC11353C0 51ADD6D0F072A6CB 3436560B3071FC1F D11D9F7E74886742 D9BEE0C FD1EA1064 C213BB55278B2F12 - key: 27F66D5244FF621E AA6F6120EDEB427F - cipher length: 64 - key length: 16 - IV: 10F99E2232BEC7F4 - clear: BF3CBF923E6C0E19 DBBB64E0FCBBFBB9 4CA3D68F117BE51F 0C1294CEC85470B6 6A799CC5D914F427 30D0C47BC9E6340C BD8E4C2E 6E5819ED 23125066DBA83477 clear: BF3CBF923E6C0E19 DBBB64E0FCBBFBB9 4CA3D68F117BE51F 0C1294CEC85470B6 6A799CC5D914F427 30D0C47BC9E6340C BD8E4C2E6E5 819ED 23125066DBA83477 Entering decrypt_3des - cipher: C25C1D1197D31CAA 87285D59A8920474 26D9182EC11353C0 51ADD6D0F072A6CB 3436560B3071FC1F D11D9F7E74886742 D9BEE0C FD1EA1064 C213BB55278B2F12 - key: 27F66D5244FF621E AA6F6120EDEB427F - cipher length: 64 - key length: 16 - IV: 32B9C802333CFBB4 - clear: A878F23C3AF5E724 2ACB3458F8D68E68 9BE4F6C007F24FD2 9AF4CE98239A4F2C 5710633D88266AFD 77EF88A7B09485D9 F07C33D7 08832E90 77382A7A51A532C1 clear: A878F23C3AF5E724 2ACB3458F8D68E68 9BE4F6C007F24FD2 9AF4CE98239A4F2C 5710633D88266AFD 77EF88A7B09485D9 F07C33D7088 32E90 77382A7A51A532C1 Entering decrypt_3des - cipher: C25C1D1197D31CAA 87285D59A8920474 26D9182EC11353C0 51ADD6D0F072A6CB 3436560B3071FC1F D11D9F7E74886742 D9BEE0C FD1EA1064 C213BB55278B2F12 - key: 27F66D5244FF621E AA6F6120EDEB427F - cipher length: 64 - key length: 16 - IV: 2FCB1A9F5B502E1B - clear: 80B7302520ACA111 223BF99421EFDA2C 60CABCB3C632A61C 3422552A07B582B7 E50E44E38DEDC300 DD9A6EB5CF3C0A63 E512FAC0 C04D3EC5 EEC551C3E845BF80 clear: 80B7302520ACA111 223BF99421EFDA2C 60CABCB3C632A61C 3422552A07B582B7 E50E44E38DEDC300 DD9A6EB5CF3C0A63 E512FAC0C04 D3EC5 EEC551C3E845BF80 Entering decrypt_3des - cipher: C25C1D1197D31CAA 87285D59A8920474 26D9182EC11353C0 51ADD6D0F072A6CB 3436560B3071FC1F D11D9F7E74886742 D9BEE0C FD1EA1064 C213BB55278B2F12 - key: 27F66D5244FF621E AA6F6120EDEB427F - cipher length: 64 - key length: 16 - IV: 355096FE3CA1E9A1 - clear: E4EDCDC436745A51 42FE9D0C71933080 6DFCAACE07FBCC22 0F5C9AF9082C8264 870362982FF90CA4 665E312FC1A8D264 DDBB27B7 3B30840E 6030D791CD849A3D clear: E4EDCDC436745A51 42FE9D0C71933080 6DFCAACE07FBCC22 0F5C9AF9082C8264 870362982FF90CA4 665E312FC1A8D264 DDBB27B73B3 0840E 6030D791CD849A3D
答案 0 :(得分：5)
设置密钥大小会导致创建新的随机密钥。如果在设置密钥和IV之前执行此操作，您将获得一致的结果。
答案 1 :(得分：0)
我无法解释原因，但用下面的代码替换它有效。我会深入研究它，如果我弄清楚，我会发表评论。
static byte[] decrypt_3des(byte[] cipher, byte[] key)
{
byte[] clear;
TripleDESCryptoServiceProvider tdes = new TripleDESCryptoServiceProvider();
tdes.Key = key;
tdes.Mode = CipherMode.CBC;
tdes.Padding = PaddingMode.None;
tdes.IV = new byte[] { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
try
{
ICryptoTransform ic = tdes.CreateDecryptor();
clear = ic.TransformFinalBlock(cipher, 0, cipher.Length);
}
finally
{
tdes.Clear();
}
return clear;
}