A useful JavaScript encryption decryption

Today, when I was doing an old project, there was a need to decrypt the parameters in the URL in JavaScript and find this useful code from the Internet:

[JavaScript]View Plaincopy

2. <script language="JavaScript" >
6. <!--Begin
14. function Encrypt (str, pwd) {
18. if (str=="")return "";
22. str = Escape (str);
26. if (!pwd | | pwd=="") { var pwd="1234";}
30. PWD = Escape (pwd);
34. if (pwd = = Null | | pwd.length <= 0) {
38. Alert ("Please enter a password with which to encrypt the message.");
42. return null;
46. }
50. var prand = "";
54. For (var i=0; i<pwd.length; i++) {
58. Prand + = Pwd.charcodeat (I). toString ();
62. }
66. var spos = Math.floor (PRAND.LENGTH/5);
70. var mult = parseint (Prand.charat (Spos) + Prand.charat (spos*2) + Prand.charat (spos*3) + Prand.charat (spos*4) + PRAND.C    Harat (spos*5));
78. var incr = Math.ceil (PWD.LENGTH/2);
82. var modu = Math.pow (2, 31)-1;
86. if (Mult < 2) {
90. Alert ("algorithm cannot find a suitable hash. Please choose a different password. /npossible considerations is to choose a more complex or longer password. ");
94. return null;
98. }
102. var salt = Math.Round (Math.random () * 1000000000)% 100000000;
106. Prand + = salt;
110. While (Prand.length >) {
114. Prand = (parseint (prand.substring (0, ten)) + parseint (prand.substring (Prand.length)). ToString ();
118. }
122. Prand = (mult * prand + incr)% Modu;
126. var enc_chr = "";
130. var enc_str = "";
134. For (var i=0; i<str.length; i++) {
138. ENC_CHR = parseint (str.charcodeat (I) ^ Math.floor ((prand/modu) * 255));
142. if (Enc_chr <) {
146. Enc_str + = "0" + enc_chr.tostring (16);
150. }Else
154. Enc_str + = enc_chr.tostring (16);
158. Prand = (mult * prand + incr)% Modu;
162. }
166. Salt = salt.tostring (16);
170. while (Salt.length < 8) Salt = "0" + salt;
174. Enc_str + = salt;
178. return enc_str;
182. }
190. function Decrypt (str, pwd) {
194. if (str=="")return "";
198. if (!pwd | | pwd=="") { var pwd="1234";}
202. PWD = Escape (pwd);
206. if (str = = Null | | Str.length < 8) {
210. Alert ("A salt value could not being extracted from the encrypted message because it's length is too short. The message cannot be decrypted. ");
214. return;
218. }
222. if (pwd = = Null | | pwd.length <= 0) {
226. Alert ("Please enter a password with which to decrypt the message.");
230. return;
234. }
238. var prand = "";
242. For (var i=0; i<pwd.length; i++) {
246. Prand + = Pwd.charcodeat (I). toString ();
250. }
254. var spos = Math.floor (PRAND.LENGTH/5);
258. var mult = parseint (Prand.charat (Spos) + Prand.charat (spos*2) + Prand.charat (spos*3) + Prand.charat (spos*4) + PRAND.C    Harat (spos*5));
262. var incr = Math.Round (PWD.LENGTH/2);
266. var modu = Math.pow (2, 31)-1;
270. var salt = parseint (str.substring (str.length-8, str.length), 16);
274. str = str.substring (0, str.length-8);
278. Prand + = salt;
282. While (Prand.length >) {
286. Prand = (parseint (prand.substring (0, ten)) + parseint (prand.substring (Prand.length)). ToString ();
290. }
294. Prand = (mult * prand + incr)% Modu;
298. var enc_chr = "";
302. var enc_str = "";
306. For (var i=0; i<str.length; i+=2) {
310. ENC_CHR = parseint (parseint (str.substring (I, i+2), +) ^ Math.floor ((prand/modu) * 255));
314. Enc_str + = String.fromCharCode (ENC_CHR);
318. Prand = (mult * prand + incr)% Modu;
322. }
326. return unescape (ENC_STR);
330. }
334. End-To
338. </script>

After encountering the encryption and decryption problem, directly write the above code into a JS file, it is done. It's convenient ....

A useful JavaScript encryption decryption