对于小型作业，我已经获得了实现DES算法而不使用Java中已有的预定义函数。我得到了它的工作，但返回的加密文本不正确。当它应该是AA 39 B9 77 7E FC 3C时，它返回6C 17 96 35 BE 47 EF 95 14.我出错的任何想法？
后续; 3月8日
根据David Koontz的建议使用this manual他将我联系到了。我相信加密开始在子密钥生成周围出错。
后续; 3月8日晚些时候
在烦恼并审查我的代码的每一步后，我发现了问题。在我的一个for循环中，我使用了int j = 0; I＆LT; 16; i ++而不是使用j。愚蠢的错误，但没有人发现它哦。已在发布的代码中进行了更正。
package des.implementation;
import java.nio.ByteBuffer;
public class DESImplementation {
private static final byte[] IP = {
58, 50, 42, 34, 26, 18, 10, 2,
60, 52, 44, 36, 28, 20, 12, 4,
62, 54, 46, 38, 30, 22, 14, 6,
64, 56, 48, 40, 32, 24, 16, 8,
57, 49, 41, 33, 25, 17, 9, 1,
59, 51, 43, 35, 27, 19, 11, 3,
61, 53, 45, 37, 29, 21, 13, 5,
63, 55, 47, 39, 31, 23, 15, 7
};
private static final byte[] FP = {
40, 8, 48, 16, 56, 24, 64, 32,
39, 7, 47, 15, 55, 23, 63, 31,
38, 6, 46, 14, 54, 22, 62, 30,
37, 5, 45, 13, 53, 21, 61, 29,
36, 4, 44, 12, 52, 20, 60, 28,
35, 3, 43, 11, 51, 19, 59, 27,
34, 2, 42, 10, 50, 18, 58, 26,
33, 1, 41, 9, 49, 17, 57, 25
};
private static final byte[] E = {
32, 1, 2, 3, 4, 5,
4, 5, 6, 7, 8, 9,
8, 9, 10, 11, 12, 13,
12, 13, 14, 15, 16, 17,
16, 17, 18, 19, 20, 21,
20, 21, 22, 23, 24, 25,
24, 25, 26, 27, 28, 29,
28, 29, 30, 31, 32, 1
};
private static final byte[][] S = { {
14, 4, 13, 1, 2, 15, 11, 8, 3, 10, 6, 12, 5, 9, 0, 7,
0, 15, 7, 4, 14, 2, 13, 1, 10, 6, 12, 11, 9, 5, 3, 8,
4, 1, 14, 8, 13, 6, 2, 11, 15, 12, 9, 7, 3, 10, 5, 0,
15, 12, 8, 2, 4, 9, 1, 7, 5, 11, 3, 14, 10, 0, 6, 13
}, {
15, 1, 8, 14, 6, 11, 3, 4, 9, 7, 2, 13, 12, 0, 5, 10,
3, 13, 4, 7, 15, 2, 8, 14, 12, 0, 1, 10, 6, 9, 11, 5,
0, 14, 7, 11, 10, 4, 13, 1, 5, 8, 12, 6, 9, 3, 2, 15,
13, 8, 10, 1, 3, 15, 4, 2, 11, 6, 7, 12, 0, 5, 14, 9
}, {
10, 0, 9, 14, 6, 3, 15, 5, 1, 13, 12, 7, 11, 4, 2, 8,
13, 7, 0, 9, 3, 4, 6, 10, 2, 8, 5, 14, 12, 11, 15, 1,
13, 6, 4, 9, 8, 15, 3, 0, 11, 1, 2, 12, 5, 10, 14, 7,
1, 10, 13, 0, 6, 9, 8, 7, 4, 15, 14, 3, 11, 5, 2, 12
}, {
7, 13, 14, 3, 0, 6, 9, 10, 1, 2, 8, 5, 11, 12, 4, 15,
13, 8, 11, 5, 6, 15, 0, 3, 4, 7, 2, 12, 1, 10, 14, 9,
10, 6, 9, 0, 12, 11, 7, 13, 15, 1, 3, 14, 5, 2, 8, 4,
3, 15, 0, 6, 10, 1, 13, 8, 9, 4, 5, 11, 12, 7, 2, 14
}, {
2, 12, 4, 1, 7, 10, 11, 6, 8, 5, 3, 15, 13, 0, 14, 9,
14, 11, 2, 12, 4, 7, 13, 1, 5, 0, 15, 10, 3, 9, 8, 6,
4, 2, 1, 11, 10, 13, 7, 8, 15, 9, 12, 5, 6, 3, 0, 14,
11, 8, 12, 7, 1, 14, 2, 13, 6, 15, 0, 9, 10, 4, 5, 3
}, {
12, 1, 10, 15, 9, 2, 6, 8, 0, 13, 3, 4, 14, 7, 5, 11,
10, 15, 4, 2, 7, 12, 9, 5, 6, 1, 13, 14, 0, 11, 3, 8,
9, 14, 15, 5, 2, 8, 12, 3, 7, 0, 4, 10, 1, 13, 11, 6,
4, 3, 2, 12, 9, 5, 15, 10, 11, 14, 1, 7, 6, 0, 8, 13
}, {
4, 11, 2, 14, 15, 0, 8, 13, 3, 12, 9, 7, 5, 10, 6, 1,
13, 0, 11, 7, 4, 9, 1, 10, 14, 3, 5, 12, 2, 15, 8, 6,
1, 4, 11, 13, 12, 3, 7, 14, 10, 15, 6, 8, 0, 5, 9, 2,
6, 11, 13, 8, 1, 4, 10, 7, 9, 5, 0, 15, 14, 2, 3, 12
}, {
13, 2, 8, 4, 6, 15, 11, 1, 10, 9, 3, 14, 5, 0, 12, 7,
1, 15, 13, 8, 10, 3, 7, 4, 12, 5, 6, 11, 0, 14, 9, 2,
7, 11, 4, 1, 9, 12, 14, 2, 0, 6, 10, 13, 15, 3, 5, 8,
2, 1, 14, 7, 4, 10, 8, 13, 15, 12, 9, 0, 3, 5, 6, 11
} };
private static final byte[] P = {
16, 7, 20, 21,
29, 12, 28, 17,
1, 15, 23, 26,
5, 18, 31, 10,
2, 8, 24, 14,
32, 27, 3, 9,
19, 13, 30, 6,
22, 11, 4, 25
};
private static final byte[] PC1 = {
57, 49, 41, 33, 25, 17, 9,
1, 58, 50, 42, 34, 26, 18,
10, 2, 59, 51, 43, 35, 27,
19, 11, 3, 60, 52, 44, 36,
63, 55, 47, 39, 31, 23, 15,
7, 62, 54, 46, 38, 30, 22,
14, 6, 61, 53, 45, 37, 29,
21, 13, 5, 28, 20, 12, 4
};
private static final byte[] PC2 = {
14, 17, 11, 24, 1, 5,
3, 28, 15, 6, 21, 10,
23, 19, 12, 4, 26, 8,
16, 7, 27, 20, 13, 2,
41, 52, 31, 37, 47, 55,
30, 40, 51, 45, 33, 48,
44, 49, 39, 56, 34, 53,
46, 42, 50, 36, 29, 32
};
private static final byte[] rotations = {
1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1
};
private static int charToNibble(char c) {
if (c>='0' && c<='9') {
return (c-'0');
} else if (c>='a' && c<='f') {
return (10+c-'a');
} else if (c>='A' && c<='F') {
return (10+c-'A');
} else {
return 0;
}
}
private static byte[] parseBytes(String s) {
s = s.replace(" ", "");
byte[] ba = new byte[s.length()/2];
if (s.length()%2 > 0) { s = s+'0'; }
for (int i=0; i<s.length(); i+=2) {
ba[i/2] = (byte) (charToNibble(s.charAt(i))<<4 | charToNibble(s.charAt(i+1)));
}
return ba;
}
private static long permute(byte[] table, int srcWidth, long src) {
long dst = 0;
for (int i=0; i<table.length; i++) {
int srcPos = srcWidth - table[i];
dst = (dst<<1) | (src>>>srcPos & 0x01);
}
return dst;
}
private static byte[] longToBytes(long x) {
ByteBuffer buffer = ByteBuffer.allocate(Long.BYTES);
buffer.putLong(x);
return buffer.array();
}
private static byte S(int boxNumber, byte src) {
src = (byte) (src&0x20 | ((src&0x01)<<4) | ((src&0x1E)>>>1));
return S[boxNumber-1][src];
}
private static int P(int src) { return (int)permute(P, 32, src&0xFFFFFFFFL); }
private static int feistel(int r, long subkey) {
long e = permute(E, 32, r&0xFFFFFFFFL);
long x = e ^ subkey;
int dst = 0;
for (int i=0; i<8; i++) {
dst>>>=4;
int s = S(8-i, (byte)(x&0x3F));
dst |= s << 28;
x>>>=6;
}
return P(dst);
}
private static long bytesToLong(byte[] bytes) {
ByteBuffer buffer = ByteBuffer.allocate(Long.BYTES);
buffer.put(bytes);
buffer.flip();
return buffer.getLong();
}
public static void main(String[] args) {
byte[] message = parseBytes("0123456789ABCDEF");
byte[] key = parseBytes("3b3898371520f75e");
byte[] ciphertext = new byte[message.length];
for(int i=0; i<message.length; i+=8){
long Lmessage = bytesToLong(message);
long Lkey = bytesToLong(key);
long subkeys[] = new long[16];
Lkey = permute(PC1, 64, Lkey);
int c = (int) (Lkey>>>28);
int d = (int) (Lkey&0x0FFFFFFF);
for (int j=0; j<16; j++) { //the problem was found here
if (rotations[j] == 1) {
c = ((c<<1) & 0x0FFFFFFF) | (c>>>27);
d = ((d<<1) & 0x0FFFFFFF) | (d>>>27);
} else {
c = ((c<<2) & 0x0FFFFFFF) | (c>>>26);
d = ((d<<2) & 0x0FFFFFFF) | (d>>>26);
}
long cd = (c&0xFFFFFFFFL)<<28 | (d&0xFFFFFFFFL);
subkeys[j] = permute(PC2, 56, cd);
}
long ip = permute(IP, 64, Lmessage);
int l = (int) (ip>>>32);
int r = (int) (ip&0xFFFFFFFFL);
for (int k=0; k<16; k++) {
int previous_l = l;
l = r;
r = previous_l^feistel(r, subkeys[k]);
}
long rl = (r&0xFFFFFFFFL)<<32 | (l&0xFFFFFFFFL);
long fp = permute(FP, 64, rl);
ciphertext = longToBytes(fp);
}
StringBuilder Message = new StringBuilder();
StringBuilder Key = new StringBuilder();
StringBuilder Cipher = new StringBuilder();
for (int i=0; i<ciphertext.length; i++) {
Message.append(String.format("%02X ",message[i]));
Key.append(String.format("%02X ",key[i]));
Cipher.append(String.format("%02X ",ciphertext[i]));
}
System.out.println("Message: "+Message.toString());
System.out.println("Key: "+Key.toString());
System.out.println("Cipher: "+Cipher.toString());
}
}
答案 0 :(得分：1)
在烦恼并审查我的代码的每一步后，我发现了问题。在我的一个for循环中，我使用了int j = 0; I＆LT; 16; i ++而不是使用j。愚蠢的错误，但没有人发现它哦。已在发布的代码中进行了更正。