javascript实现des解密加密全过程

//Paul Tero, July 2001 
//http://www.tero.co.uk/des/ 
// 
//Optimised for performance with large blocks by Michael Hayworth, November 2001 
//http://www.netdealing.com 
// 
//THIS SOFTWARE IS PROVIDED "AS IS" AND 
//ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 
//IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 
//ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 
//FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 
//DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 
//OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 
//HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 
//LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 
//OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 
//SUCH DAMAGE. 

//des 
//this takes the key, the message, and whether to encrypt or decrypt 
function des (key, message, encrypt, mode, iv, padding) { 
//declaring this locally speeds things up a bit 
var spfunction1 = new Array (0x1010400,0,0x10000,0x1010404,0x1010004,0x10404,0x4,0x10000,0x400,0x1010400,0x1010404,0x400,0x1000404,0x1010004,0x1000000,0x4,0x404,0x1000400,0x1000400,0x10400,0x10400,0x1010000,0x1010000,0x1000404,0x10004,0x1000004,0x1000004,0x10004,0,0x404,0x10404,0x1000000,0x10000,0x1010404,0x4,0x1010000,0x1010400,0x1000000,0x1000000,0x400,0x1010004,0x10000,0x10400,0x1000004,0x400,0x4,0x1000404,0x10404,0x1010404,0x10004,0x1010000,0x1000404,0x1000004,0x404,0x10404,0x1010400,0x404,0x1000400,0x1000400,0,0x10004,0x10400,0,0x1010004); 
var spfunction2 = new Array (-0x7fef7fe0,-0x7fff8000,0x8000,0x108020,0x100000,0x20,-0x7fefffe0,-0x7fff7fe0,-0x7fffffe0,-0x7fef7fe0,-0x7fef8000,-0x80000000,-0x7fff8000,0x100000,0x20,-0x7fefffe0,0x108000,0x100020,-0x7fff7fe0,0,-0x80000000,0x8000,0x108020,-0x7ff00000,0x100020,-0x7fffffe0,0,0x108000,0x8020,-0x7fef8000,-0x7ff00000,0x8020,0,0x108020,-0x7fefffe0,0x100000,-0x7fff7fe0,-0x7ff00000,-0x7fef8000,0x8000,-0x7ff00000,-0x7fff8000,0x20,-0x7fef7fe0,0x108020,0x20,0x8000,-0x80000000,0x8020,-0x7fef8000,0x100000,-0x7fffffe0,0x100020,-0x7fff7fe0,-0x7fffffe0,0x100020,0x108000,0,-0x7fff8000,0x8020,-0x80000000,-0x7fefffe0,-0x7fef7fe0,0x108000); 
var spfunction3 = new Array (0x208,0x8020200,0,0x8020008,0x8000200,0,0x20208,0x8000200,0x20008,0x8000008,0x8000008,0x20000,0x8020208,0x20008,0x8020000,0x208,0x8000000,0x8,0x8020200,0x200,0x20200,0x8020000,0x8020008,0x20208,0x8000208,0x20200,0x20000,0x8000208,0x8,0x8020208,0x200,0x8000000,0x8020200,0x8000000,0x20008,0x208,0x20000,0x8020200,0x8000200,0,0x200,0x20008,0x8020208,0x8000200,0x8000008,0x200,0,0x8020008,0x8000208,0x20000,0x8000000,0x8020208,0x8,0x20208,0x20200,0x8000008,0x8020000,0x8000208,0x208,0x8020000,0x20208,0x8,0x8020008,0x20200); 
var spfunction4 = new Array (0x802001,0x2081,0x2081,0x80,0x802080,0x800081,0x800001,0x2001,0,0x802000,0x802000,0x802081,0x81,0,0x800080,0x800001,0x1,0x2000,0x800000,0x802001,0x80,0x800000,0x2001,0x2080,0x800081,0x1,0x2080,0x800080,0x2000,0x802080,0x802081,0x81,0x800080,0x800001,0x802000,0x802081,0x81,0,0,0x802000,0x2080,0x800080,0x800081,0x1,0x802001,0x2081,0x2081,0x80,0x802081,0x81,0x1,0x2000,0x800001,0x2001,0x802080,0x800081,0x2001,0x2080,0x800000,0x802001,0x80,0x800000,0x2000,0x802080); 
var spfunction5 = new Array (0x100,0x2080100,0x2080000,0x42000100,0x80000,0x100,0x40000000,0x2080000,0x40080100,0x80000,0x2000100,0x40080100,0x42000100,0x42080000,0x80100,0x40000000,0x2000000,0x40080000,0x40080000,0,0x40000100,0x42080100,0x42080100,0x2000100,0x42080000,0x40000100,0,0x42000000,0x2080100,0x2000000,0x42000000,0x80100,0x80000,0x42000100,0x100,0x2000000,0x40000000,0x2080000,0x42000100,0x40080100,0x2000100,0x40000000,0x42080000,0x2080100,0x40080100,0x100,0x2000000,0x42080000,0x42080100,0x80100,0x42000000,0x42080100,0x2080000,0,0x40080000,0x42000000,0x80100,0x2000100,0x40000100,0x80000,0,0x40080000,0x2080100,0x40000100); 
var spfunction6 = new Array (0x20000010,0x20400000,0x4000,0x20404010,0x20400000,0x10,0x20404010,0x400000,0x20004000,0x404010,0x400000,0x20000010,0x400010,0x20004000,0x20000000,0x4010,0,0x400010,0x20004010,0x4000,0x404000,0x20004010,0x10,0x20400010,0x20400010,0,0x404010,0x20404000,0x4010,0x404000,0x20404000,0x20000000,0x20004000,0x10,0x20400010,0x404000,0x20404010,0x400000,0x4010,0x20000010,0x400000,0x20004000,0x20000000,0x4010,0x20000010,0x20404010,0x404000,0x20400000,0x404010,0x20404000,0,0x20400010,0x10,0x4000,0x20400000,0x404010,0x4000,0x400010,0x20004010,0,0x20404000,0x20000000,0x400010,0x20004010); 
var spfunction7 = new Array (0x200000,0x4200002,0x4000802,0,0x800,0x4000802,0x200802,0x4200800,0x4200802,0x200000,0,0x4000002,0x2,0x4000000,0x4200002,0x802,0x4000800,0x200802,0x200002,0x4000800,0x4000002,0x4200000,0x4200800,0x200002,0x4200000,0x800,0x802,0x4200802,0x200800,0x2,0x4000000,0x200800,0x4000000,0x200800,0x200000,0x4000802,0x4000802,0x4200002,0x4200002,0x2,0x200002,0x4000000,0x4000800,0x200000,0x4200800,0x802,0x200802,0x4200800,0x802,0x4000002,0x4200802,0x4200000,0x200800,0,0x2,0x4200802,0,0x200802,0x4200000,0x800,0x4000002,0x4000800,0x800,0x200002); 
var spfunction8 = new Array (0x10001040,0x1000,0x40000,0x10041040,0x10000000,0x10001040,0x40,0x10000000,0x40040,0x10040000,0x10041040,0x41000,0x10041000,0x41040,0x1000,0x40,0x10040000,0x10000040,0x10001000,0x1040,0x41000,0x40040,0x10040040,0x10041000,0x1040,0,0,0x10040040,0x10000040,0x10001000,0x41040,0x40000,0x41040,0x40000,0x10041000,0x1000,0x40,0x10040040,0x1000,0x41040,0x10001000,0x40,0x10000040,0x10040000,0x10040040,0x10000000,0x40000,0x10001040,0,0x10041040,0x40040,0x10000040,0x10040000,0x10001000,0x10001040,0,0x10041040,0x41000,0x41000,0x1040,0x1040,0x40040,0x10000000,0x10041000); 

//create the 16 or 48 subkeys we will need 
var keys = des_createKeys (key); 
var m=0, i, j, temp, temp2, right1, right2, left, right, looping; 
var cbcleft, cbcleft2, cbcright, cbcright2 
var endloop, loopinc; 
var len = message.length; 
var chunk = 0; 
//set up the loops for single and triple des 
var iterations = keys.length == 32 ? 3 : 9; //single or triple des 
if (iterations == 3) {looping = encrypt ? new Array (0, 32, 2) : new Array (30, -2, -2);} 
else {looping = encrypt ? new Array (0, 32, 2, 62, 30, -2, 64, 96, 2) : new Array (94, 62, -2, 32, 64, 2, 30, -2, -2);} 

//pad the message depending on the padding parameter 
if (padding == 2) message += " "; //pad the message with spaces 
else if (padding == 1) {temp = 8-(len%8); message += String.fromCharCode (temp,temp,temp,temp,temp,temp,temp,temp); if (temp==8) len+=8;} //PKCS7 padding 
else if (!padding) message += "\0\0\0\0\0\0\0\0"; //pad the message out with null bytes 

//store the result here 
result = ""; 
tempresult = ""; 

if (mode == 1) { //CBC mode 
cbcleft = (iv.charCodeAt(m++) << 24) | (iv.charCodeAt(m++) << 16) | (iv.charCodeAt(m++) << 8) | iv.charCodeAt(m++); 
cbcright = (iv.charCodeAt(m++) << 24) | (iv.charCodeAt(m++) << 16) | (iv.charCodeAt(m++) << 8) | iv.charCodeAt(m++); 
m=0; 
} 

//loop through each 64 bit chunk of the message 
while (m < len) { 
left = (message.charCodeAt(m++) << 24) | (message.charCodeAt(m++) << 16) | (message.charCodeAt(m++) << 8) | message.charCodeAt(m++); 
right = (message.charCodeAt(m++) << 24) | (message.charCodeAt(m++) << 16) | (message.charCodeAt(m++) << 8) | message.charCodeAt(m++); 

//for Cipher Block Chaining mode, xor the message with the previous result 
if (mode == 1) {if (encrypt) {left ^= cbcleft; right ^= cbcright;} else {cbcleft2 = cbcleft; cbcright2 = cbcright; cbcleft = left; cbcright = right;}} 

//first each 64 but chunk of the message must be permuted according to IP 
temp = ((left >>> 4) ^ right) & 0x0f0f0f0f; right ^= temp; left ^= (temp << 4); 
temp = ((left >>> 16) ^ right) & 0x0000ffff; right ^= temp; left ^= (temp << 16); 
temp = ((right >>> 2) ^ left) & 0x33333333; left ^= temp; right ^= (temp << 2); 
temp = ((right >>> 8) ^ left) & 0x00ff00ff; left ^= temp; right ^= (temp << 8); 
temp = ((left >>> 1) ^ right) & 0x55555555; right ^= temp; left ^= (temp << 1); 

left = ((left << 1) | (left >>> 31)); 
right = ((right << 1) | (right >>> 31)); 

//do this either 1 or 3 times for each chunk of the message 
for (j=0; j<iterations; j+=3) { 
endloop = looping[j+1]; 
loopinc = looping[j+2]; 
//now go through and perform the encryption or decryption 
for (i=looping[j]; i!=endloop; i+=loopinc) { //for efficiency 
right1 = right ^ keys[i]; 
right2 = ((right >>> 4) | (right << 28)) ^ keys[i+1]; 
//the result is attained by passing these bytes through the S selection functions 
temp = left; 
left = right; 
right = temp ^ (spfunction2[(right1 >>> 24) & 0x3f] | spfunction4[(right1 >>> 16) & 0x3f] 
| spfunction6[(right1 >>> 8) & 0x3f] | spfunction8[right1 & 0x3f] 
| spfunction1[(right2 >>> 24) & 0x3f] | spfunction3[(right2 >>> 16) & 0x3f] 
| spfunction5[(right2 >>> 8) & 0x3f] | spfunction7[right2 & 0x3f]); 
} 
temp = left; left = right; right = temp; //unreverse left and right 
} //for either 1 or 3 iterations 

//move then each one bit to the right 
left = ((left >>> 1) | (left << 31)); 
right = ((right >>> 1) | (right << 31)); 

//now perform IP-1, which is IP in the opposite direction 
temp = ((left >>> 1) ^ right) & 0x55555555; right ^= temp; left ^= (temp << 1); 
temp = ((right >>> 8) ^ left) & 0x00ff00ff; left ^= temp; right ^= (temp << 8); 
temp = ((right >>> 2) ^ left) & 0x33333333; left ^= temp; right ^= (temp << 2); 
temp = ((left >>> 16) ^ right) & 0x0000ffff; right ^= temp; left ^= (temp << 16); 
temp = ((left >>> 4) ^ right) & 0x0f0f0f0f; right ^= temp; left ^= (temp << 4); 

//for Cipher Block Chaining mode, xor the message with the previous result 
if (mode == 1) {if (encrypt) {cbcleft = left; cbcright = right;} else {left ^= cbcleft2; right ^= cbcright2;}} 
tempresult += String.fromCharCode ((left>>>24), ((left>>>16) & 0xff), ((left>>>8) & 0xff), (left & 0xff), (right>>>24), ((right>>>16) & 0xff), ((right>>>8) & 0xff), (right & 0xff)); 

chunk += 8; 
if (chunk == 512) {result += tempresult; tempresult = ""; chunk = 0;} 
} //for every 8 characters, or 64 bits in the message 

//return the result as an array 
return result + tempresult; 
} //end of des 
//des_createKeys 
//this takes as input a 64 bit key (even though only 56 bits are used) 
//as an array of 2 integers, and returns 16 48 bit keys 
function des_createKeys (key) { 
//declaring this locally speeds things up a bit 
pc2bytes0 = new Array (0,0x4,0x20000000,0x20000004,0x10000,0x10004,0x20010000,0x20010004,0x200,0x204,0x20000200,0x20000204,0x10200,0x10204,0x20010200,0x20010204); 
pc2bytes1 = new Array (0,0x1,0x100000,0x100001,0x4000000,0x4000001,0x4100000,0x4100001,0x100,0x101,0x100100,0x100101,0x4000100,0x4000101,0x4100100,0x4100101); 
pc2bytes2 = new Array (0,0x8,0x800,0x808,0x1000000,0x1000008,0x1000800,0x1000808,0,0x8,0x800,0x808,0x1000000,0x1000008,0x1000800,0x1000808); 
pc2bytes3 = new Array (0,0x200000,0x8000000,0x8200000,0x2000,0x202000,0x8002000,0x8202000,0x20000,0x220000,0x8020000,0x8220000,0x22000,0x222000,0x8022000,0x8222000); 
pc2bytes4 = new Array (0,0x40000,0x10,0x40010,0,0x40000,0x10,0x40010,0x1000,0x41000,0x1010,0x41010,0x1000,0x41000,0x1010,0x41010); 
pc2bytes5 = new Array (0,0x400,0x20,0x420,0,0x400,0x20,0x420,0x2000000,0x2000400,0x2000020,0x2000420,0x2000000,0x2000400,0x2000020,0x2000420); 
pc2bytes6 = new Array (0,0x10000000,0x80000,0x10080000,0x2,0x10000002,0x80002,0x10080002,0,0x10000000,0x80000,0x10080000,0x2,0x10000002,0x80002,0x10080002); 
pc2bytes7 = new Array (0,0x10000,0x800,0x10800,0x20000000,0x20010000,0x20000800,0x20010800,0x20000,0x30000,0x20800,0x30800,0x20020000,0x20030000,0x20020800,0x20030800); 
pc2bytes8 = new Array (0,0x40000,0,0x40000,0x2,0x40002,0x2,0x40002,0x2000000,0x2040000,0x2000000,0x2040000,0x2000002,0x2040002,0x2000002,0x2040002); 
pc2bytes9 = new Array (0,0x10000000,0x8,0x10000008,0,0x10000000,0x8,0x10000008,0x400,0x10000400,0x408,0x10000408,0x400,0x10000400,0x408,0x10000408); 
pc2bytes10 = new Array (0,0x20,0,0x20,0x100000,0x100020,0x100000,0x100020,0x2000,0x2020,0x2000,0x2020,0x102000,0x102020,0x102000,0x102020); 
pc2bytes11 = new Array (0,0x1000000,0x200,0x1000200,0x200000,0x1200000,0x200200,0x1200200,0x4000000,0x5000000,0x4000200,0x5000200,0x4200000,0x5200000,0x4200200,0x5200200); 
pc2bytes12 = new Array (0,0x1000,0x8000000,0x8001000,0x80000,0x81000,0x8080000,0x8081000,0x10,0x1010,0x8000010,0x8001010,0x80010,0x81010,0x8080010,0x8081010); 
pc2bytes13 = new Array (0,0x4,0x100,0x104,0,0x4,0x100,0x104,0x1,0x5,0x101,0x105,0x1,0x5,0x101,0x105); 

//how many iterations (1 for des, 3 for triple des) 
var iterations = key.length > 8 ? 3 : 1; //changed by Paul 16/6/2007 to use Triple DES for 9+ byte keys 
//stores the return keys 
var keys = new Array (32 * iterations); 
//now define the left shifts which need to be done 
var shifts = new Array (0, 0, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 0); 
//other variables 
var lefttemp, righttemp, m=0, n=0, temp; 

for (var j=0; j<iterations; j++) { //either 1 or 3 iterations 
left = (key.charCodeAt(m++) << 24) | (key.charCodeAt(m++) << 16) | (key.charCodeAt(m++) << 8) | key.charCodeAt(m++); 
right = (key.charCodeAt(m++) << 24) | (key.charCodeAt(m++) << 16) | (key.charCodeAt(m++) << 8) | key.charCodeAt(m++); 

temp = ((left >>> 4) ^ right) & 0x0f0f0f0f; right ^= temp; left ^= (temp << 4); 
temp = ((right >>> -16) ^ left) & 0x0000ffff; left ^= temp; right ^= (temp << -16); 
temp = ((left >>> 2) ^ right) & 0x33333333; right ^= temp; left ^= (temp << 2); 
temp = ((right >>> -16) ^ left) & 0x0000ffff; left ^= temp; right ^= (temp << -16); 
temp = ((left >>> 1) ^ right) & 0x55555555; right ^= temp; left ^= (temp << 1); 
temp = ((right >>> 8) ^ left) & 0x00ff00ff; left ^= temp; right ^= (temp << 8); 
temp = ((left >>> 1) ^ right) & 0x55555555; right ^= temp; left ^= (temp << 1); 

//the right side needs to be shifted and to get the last four bits of the left side 
temp = (left << 8) | ((right >>> 20) & 0x000000f0); 
//left needs to be put upside down 
left = (right << 24) | ((right << 8) & 0xff0000) | ((right >>> 8) & 0xff00) | ((right >>> 24) & 0xf0); 
right = temp; 

//now go through and perform these shifts on the left and right keys 
for (var i=0; i < shifts.length; i++) { 
//shift the keys either one or two bits to the left 
if (shifts[i]) {left = (left << 2) | (left >>> 26); right = (right << 2) | (right >>> 26);} 
else {left = (left << 1) | (left >>> 27); right = (right << 1) | (right >>> 27);} 
left &= -0xf; right &= -0xf; 

//now apply PC-2, in such a way that E is easier when encrypting or decrypting 
//this conversion will look like PC-2 except only the last 6 bits of each byte are used 
//rather than 48 consecutive bits and the order of lines will be according to 
//how the S selection functions will be applied: S2, S4, S6, S8, S1, S3, S5, S7 
lefttemp = pc2bytes0[left >>> 28] | pc2bytes1[(left >>> 24) & 0xf] 
| pc2bytes2[(left >>> 20) & 0xf] | pc2bytes3[(left >>> 16) & 0xf] 
| pc2bytes4[(left >>> 12) & 0xf] | pc2bytes5[(left >>> 8) & 0xf] 
| pc2bytes6[(left >>> 4) & 0xf]; 
righttemp = pc2bytes7[right >>> 28] | pc2bytes8[(right >>> 24) & 0xf] 
| pc2bytes9[(right >>> 20) & 0xf] | pc2bytes10[(right >>> 16) & 0xf] 
| pc2bytes11[(right >>> 12) & 0xf] | pc2bytes12[(right >>> 8) & 0xf] 
| pc2bytes13[(right >>> 4) & 0xf]; 
temp = ((righttemp >>> 16) ^ lefttemp) & 0x0000ffff; 
keys[n++] = lefttemp ^ temp; keys[n++] = righttemp ^ (temp << 16); 
} 
} //for each iterations 
//return the keys we've created 
return keys; 
} //end of des_createKeys 
////////////////////////////// TEST ////////////////////////////// 
function stringToHex (s) { 
var r = "0x"; 
var hexes = new Array ("0","1","2","3","4","5","6","7","8","9","a","b","c","d","e","f"); 
for (var i=0; i<s.length; i++) {r += hexes [s.charCodeAt(i) >> 4] + hexes [s.charCodeAt(i) & 0xf];} 
return r; 
} 

function hexToString (h) { 
var r = ""; 
for (var i= (h.substr(0, 2)=="0x")?2:0; i<h.length; i+=2) {r += String.fromCharCode (parseInt (h.substr (i, 2), 16));} 
return r; 
} 

var key = "this is a 24 byte key !!"; 
var message = "This is a test message"; 
var ciphertext = des (key, message, 1, 0); 
document.writeln ("DES Test: " + stringToHex (ciphertext));