js版RSA算法

// RSA, a suite of routines for performing RSA public-key computations in// JavaScript.//

// Requires BigInt.js and Barrett.js.//

// Copyright 1998-2005 David Shapiro.//

// You may use, re-use, abuse, copy, and modify this code to your liking, but// please keep this header.//

// Thanks!//

// Dave Shapiro

// dave@ohdave.com

function RSAKeyPair(encryptionExponent, decryptionExponent, modulus){

this.e = biFromHex(encryptionExponent);this.d = biFromHex(decryptionExponent);this.m = biFromHex(modulus);// We can do two bytes per digit, so

// chunkSize = 2 * (number of digits in modulus - 1).

// Since biHighIndex returns the high index, not the number of digits, 1 has// already been subtracted.

this.chunkSize = 2 * biHighIndex(this.m);this.radix = 16;

this.barrett = new BarrettMu(this.m);}

function twoDigit(n){

return (n < 10 ? \"0\" : \"\") + String(n);}

function encryptedString(key, s)

// Altered by Rob Saunders (rob@robsaunders.net). New routine pads the// string after it has been converted to an array. This fixes an// incompatibility with Flash MX's ActionScript.{

var a = new Array();var sl = s.length;var i = 0;

while (i < sl) {

a[i] = s.charCodeAt(i);i++;}

while (a.length % key.chunkSize != 0) {a[i++] = 0;}

var al = a.length;var result = \"\";var j, k, block;

for (i = 0; i < al; i += key.chunkSize) {block = new BigInt();j = 0;

for (k = i; k < i + key.chunkSize; ++j) {block.digits[j] = a[k++];

block.digits[j] += a[k++] << 8;}

var crypt = key.barrett.powMod(block, key.e);

var text = key.radix == 16 ? biToHex(crypt) : biToString(crypt, key.radix);result += text + \" \";}

return result.substring(0, result.length - 1); // Remove last space.

}

function decryptedString(key, s){

var blocks = s.split(\" \");var result = \"\";var i, j, block;

for (i = 0; i < blocks.length; ++i) {var bi;

if (key.radix == 16) {

bi = biFromHex(blocks[i]);}

else {

bi = biFromString(blocks[i], key.radix);}

block = key.barrett.powMod(bi, key.d);for (j = 0; j <= biHighIndex(block); ++j) {

result += String.fromCharCode(block.digits[j] & 255,block.digits[j] >> 8);}}

// Remove trailing null, if any.

if (result.charCodeAt(result.length - 1) == 0) {result = result.substring(0, result.length - 1);}

return result;}

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