【发布时间】：2018-04-09 20:55:38
【问题描述】：
我发现了一个问题，Elephantik 的回答基本上回答了我的问题： DES Initialization Vector in C#
我有一个使用 DES.EXE 命令行工具加密的文件。我可以使用以下命令对其进行解密：“des -D -k YSTxyHBH file.cr file.txt”
使用这个命令我得到一个解密的 file.txt，但我需要用 Java 解密这个文件。
所以我尝试将解决方案从 Elephantik 转移到 Java，但我的解决方案肯定有问题，因为结果我在调用 decryptData(...) 方法时只能得到一些加密文本。
public byte[] decryptData(byte input[], String password) throws Exception {
byte[] result = null;
//Cipher cipher = Cipher.getInstance("DES/CBC/PKCS5Padding");
Cipher cipher = Cipher.getInstance("DES/CBC/NoPadding");
//byte[] iv = { 0, 0, 0, 0, 0, 0, 0, 0 };
byte[] iv = { -128, -128, -128, -128, -128, -128, -128, -128 };
IvParameterSpec ivspec = new IvParameterSpec(iv);
cipher.init(Cipher.DECRYPT_MODE, generateSecretKey(passwordToKey(password)), ivspec);
result = cipher.doFinal(input);
return result;
}
protected SecretKey generateSecretKey(byte[] key) throws Exception {
SecretKeyFactory factory = SecretKeyFactory.getInstance("DES");
KeySpec keySpec = new DESKeySpec(key);
SecretKey secretKey = factory.generateSecret(keySpec);
return secretKey;
}
public byte[] passwordToKey(String password) throws Exception
{
if (password == null)
throw new IllegalArgumentException("password");
if (password == "")
throw new IllegalArgumentException("password");
byte[] key = new byte[8];
for (int i = 0; i < password.length(); i++)
{
int c = (int)password.charAt(i);
if ((i % 16) < 8)
{
key[i % 8] ^= (byte)(c << 1);
}
else
{
// reverse bits e.g. 11010010 -> 01001011
c = (((c << 4) & 0xf0) | ((c >> 4) & 0x0f));
c = (((c << 2) & 0xcc) | ((c >> 2) & 0x33));
c = (((c << 1) & 0xaa) | ((c >> 1) & 0x55));
key[7 - (i % 8)] ^= (byte)c;
}
}
addOddParity(key);
byte[] target = new byte[8];
ByteArrayOutputStream outputStream = new ByteArrayOutputStream( );
outputStream.write(password.getBytes("US-ASCII"));
outputStream.write(new byte[8]);
byte[] temp = outputStream.toByteArray();
outputStream = new ByteArrayOutputStream( );
for (int i = 0; i < (password.length() + (8 - (password.length() % 8)) % 8); ++i) {
outputStream.write(temp[i]);
}
byte[] passwordBuffer = outputStream.toByteArray();
Cipher cipher = Cipher.getInstance("DES/CBC/NoPadding");
//byte[] iv = { 0, 0, 0, 0, 0, 0, 0, 0 };
byte[] iv = { -128, -128, -128, -128, -128, -128, -128, -128 };
IvParameterSpec ivspec = new IvParameterSpec(iv);
cipher.init(Cipher.ENCRYPT_MODE, generateSecretKey(key), ivspec);
for (int x = 0; x < passwordBuffer.length / 8; ++x)
{
cipher.update(passwordBuffer, 8 * x, 8, target, 0);
}
addOddParity(target);
return target;
}
private void addOddParity(byte[] buffer)
{
for (int i = 0; i < buffer.length; ++i)
{
buffer[i] = _oddParityTable[buffer[i] & 0xFF];
}
}
private static byte[] _oddParityTable = {
-127,-127,-126,-126,-124,-124,-121,-121,-120,-120,-117,-117,-115,-115,-114,-114,
-112,-112,-109,-109,-107,-107,-106,-106,-103,-103,-102,-102,-100,-100, -97, -97,
-96, -96, -93, -93, -91, -91, -90, -90, -87, -87, -86, -86, -84, -84, -81, -81,
-79, -79, -78, -78, -76, -76, -73, -73, -72, -72, -69, -69, -67, -67, -66, -66,
-64, -64, -61, -61, -59, -59, -58, -58, -55, -55, -54, -54, -52, -52, -49, -49,
-47, -47, -46, -46, -44, -44, -41, -41, -40, -40, -37, -37, -35, -35, -34, -34,
-31, -31, -30, -30, -28, -28, -25, -25, -24, -24, -21, -21, -19, -19, -18, -18,
-16, -16, -13, -13, -11, -11, -10, -10, -7, -7, -6, -6, -4, -4, -1, -1,
0, 0, 3, 3, 5, 5, 6, 6, 9, 9, 10, 10, 12, 12, 15, 15,
17, 17, 18, 18, 20, 20, 23, 23, 24, 24, 27, 27, 29, 29, 30, 30,
33, 33, 34, 34, 36, 36, 39, 39, 40, 40, 43, 43, 45, 45, 46, 46,
48, 48, 51, 51, 53, 53, 54, 54, 57, 57, 58, 58, 60, 60, 63, 63,
65, 65, 66, 66, 68, 68, 71, 71, 72, 72, 75, 75, 77, 77, 78, 78,
80, 80, 83, 83, 85, 85, 86, 86, 89, 89, 90, 90, 92, 92, 95, 95,
96, 96, 99, 99, 101, 101, 102, 102, 105, 105, 106, 106, 108, 108, 111, 111,
113, 113, 114, 114, 116, 116, 119, 119, 120, 120, 123, 123, 125, 125, 126, 126
};
【问题讨论】：
-
你能更清楚地描述你得到什么以及期望得到什么吗？你能给出一个示例输出吗？
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我有一个 test.txt 文件，其中包含文本“Hello”。如果我调用命令“des -E -k testkeyy test.txt test.cr”，我会得到一个文件 test.cr，其中包含文本“i¹^,ua-”。当我调用命令“des -D -k testkeyy test.cr test.txt”时，我再次得到一个带有文本“Hello”的文件 test.txt。如果我从文件和密钥“testkeyy”中获取字节数组调用decryptData（...）方法，我会得到输出“^！Èe¹õ2ª”。
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嗨@MichaelP。我也遇到了同样的问题，请问您找到解决办法了吗？
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我有 Java 和 C# 的解决方案。如果有人需要，请在此处发送消息，我会发布答案。
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@DmitryKazakov 我需要 C# 中的解决方案，您可以将其作为答案发布到：stackoverflow.com/questions/59770092/…
标签： java encryption des