JavaScript encrypts the parameters in the URL to decrypt the code _javascript tips

Today, while doing an old project, I encountered a requirement to encrypt the parameters in the URL in JavaScript, and found this useful code from the Internet:

Copy Code code as follows:

<script language= "JavaScript" >
<!--Begin
function Encrypt (str, pwd) {
if (str== "") return "";
str = Escape (str);
if (!pwd | | pwd== "") {var pwd= "1234";}
PWD = Escape (pwd);
if (pwd = null | | pwd.length <= 0) {
Alert ("Please enter a password with which to encrypt");
return null;
}
var prand = "";
for (Var i=0; i<pwd.length; i++) {
Prand + + pwd.charcodeat (I). toString ();
}
var spos = Math.floor (PRAND.LENGTH/5);
var mult = parseint (Prand.charat (Spos) + Prand.charat (spos*2) + Prand.charat (spos*3) + Prand.charat (sPos*4) + Prand.charA T (spos*5));
var incr = Math.ceil (PWD.LENGTH/2);
var modu = Math.pow (2, 31)-1;
if (Mult < 2) {
Alert ("algorithm cannot find a suitable hash. Please choose a different password. /npossible considerations are to choose a more complex or longer password. ");
return null;
}
var salt = Math.Round (Math.random () * 1000000000)% 100000000;
Prand + + salt;
while (Prand.length > 10) {
Prand = (parseint (prand.substring (0)) + parseint (prand.substring (prand.length))). ToString ();
}
Prand = (mult * prand + incr)% Modu;
var enc_chr = "";
var enc_str = "";
for (Var i=0; i<str.length; i++) {
ENC_CHR = parseint (str.charcodeat (I) ^ Math.floor ((prand/modu) * 255));
if (ENC_CHR < 16) {
Enc_str + = "0" + enc_chr.tostring (16);
}else
Enc_str + + enc_chr.tostring (16);
Prand = (mult * prand + incr)% Modu;
}
Salt = salt.tostring (16);
while (Salt.length < 8) Salt = "0" + salt;
Enc_str + + salt;
return enc_str;
}
function Decrypt (str, pwd) {
if (str== "") return "";
if (!pwd | | pwd== "") {var pwd= "1234";}
PWD = Escape (pwd);
if (str = NULL | | Str.length < 8) {
Alert ("A salt value could not to be extracted to the encrypted message because it ' s length is too short. The message cannot be decrypted. ");
Return
}
if (pwd = null | | pwd.length <= 0) {
Alert ("Please enter a password with which to decrypt");
Return
}
var prand = "";
for (Var i=0; i<pwd.length; i++) {
Prand + + pwd.charcodeat (I). toString ();
}
var spos = Math.floor (PRAND.LENGTH/5);
var mult = parseint (Prand.charat (Spos) + Prand.charat (spos*2) + Prand.charat (spos*3) + Prand.charat (sPos*4) + Prand.charA T (spos*5));
var incr = Math.Round (PWD.LENGTH/2);
var modu = Math.pow (2, 31)-1;
var salt = parseint (str.substring (str.length-8, str.length), 16);
str = str.substring (0, str.length-8);
Prand + + salt;
while (Prand.length > 10) {
Prand = (parseint (prand.substring (0)) + parseint (prand.substring (prand.length))). ToString ();
}
Prand = (mult * prand + incr)% Modu;
var enc_chr = "";
var enc_str = "";
for (Var i=0; i<str.length; i+=2) {
ENC_CHR = parseint (parseint (str.substring (I, i+2),) ^ Math.floor ((prand/modu) * 255));
Enc_str + + string.fromcharcode (ENC_CHR);
Prand = (mult * prand + incr)% Modu;
}
return unescape (ENC_STR);
}
End-->
</script>

Later encountered encryption and decryption problem, directly to write the above code a JS file, it is done. It's convenient ....