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71 lines
2.9 KiB
JavaScript
71 lines
2.9 KiB
JavaScript
function encrypt(str, pwd) {
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if (pwd == null || pwd.length <= 0) {
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/*alert("Please enter a password with which to encrypt the message.");*/
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return null;
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}
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var prand = "";
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for (var i = 0; i < pwd.length; i++) {
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prand += pwd.charCodeAt(i).toString();
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}
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var sPos = Math.floor(prand.length / 5);
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var mult = parseInt(prand.charAt(sPos) + prand.charAt(sPos * 2) + prand.charAt(sPos * 3) + prand.charAt(sPos * 4) + prand.charAt(sPos * 5));
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var incr = Math.ceil(pwd.length / 2);
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var modu = Math.pow(2, 31) - 1;
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if (mult < 2) {
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/*alert("Algorithm cannot find a suitable hash. Please choose a different password. \nPossible considerations are to choose a more complex or longer password.");*/
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return null;
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}
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var salt = Math.round(Math.random() * 1000000000) % 100000000;
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prand += salt;
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while (prand.length > 10) {
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prand = (parseInt(prand.substring(0, 10)) + parseInt(prand.substring(10, prand.length))).toString();
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}
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prand = (mult * prand + incr) % modu;
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var enc_chr = "";
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var enc_str = "";
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for (var i = 0; i < str.length; i++) {
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enc_chr = parseInt(str.charCodeAt(i) ^ Math.floor((prand / modu) * 255));
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if (enc_chr < 16) {
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enc_str += "0" + enc_chr.toString(16);
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} else enc_str += enc_chr.toString(16);
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prand = (mult * prand + incr) % modu;
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}
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salt = salt.toString(16);
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while (salt.length < 8) salt = "0" + salt;
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enc_str += salt;
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return enc_str;
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}
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function decrypt(str, pwd) {
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if (str == null || str.length < 8) {
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/*alert("A salt value could not be extracted from the encrypted message because its length is too short. The message cannot be decrypted.");*/
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return;
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}
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if (pwd == null || pwd.length <= 0) {
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/*alert("Please enter a password with which to decrypt the message.");*/
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return;
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}
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var prand = "";
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for (var i = 0; i < pwd.length; i++) {
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prand += pwd.charCodeAt(i).toString();
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}
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var sPos = Math.floor(prand.length / 5);
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var mult = parseInt(prand.charAt(sPos) + prand.charAt(sPos * 2) + prand.charAt(sPos * 3) + prand.charAt(sPos * 4) + prand.charAt(sPos * 5));
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var incr = Math.round(pwd.length / 2);
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var modu = Math.pow(2, 31) - 1;
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var salt = parseInt(str.substring(str.length - 8, str.length), 16);
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str = str.substring(0, str.length - 8);
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prand += salt;
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while (prand.length > 10) {
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prand = (parseInt(prand.substring(0, 10)) + parseInt(prand.substring(10, prand.length))).toString();
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}
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prand = (mult * prand + incr) % modu;
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var enc_chr = "";
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var enc_str = "";
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for (var i = 0; i < str.length; i += 2) {
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enc_chr = parseInt(parseInt(str.substring(i, i + 2), 16) ^ Math.floor((prand / modu) * 255));
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enc_str += String.fromCharCode(enc_chr);
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prand = (mult * prand + incr) % modu;
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}
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return enc_str;
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} |