[Zefir]

Tiny Encryption Algorithm (TEA).
Simple and fast symmetric-key algorithm cipher.

.: Description

Tiny Encryption Algorithm (TEA) is a block cipher notable for its simplicity of description and implementation, typically a few lines of code. It was designed by David Wheeler and Roger Needham of the Cambridge Computer Laboratory; it was first presented at the Fast Software Encryption workshop in Leuven in 1994, and first published in the proceedings of that workshop.

The cipher is not subject to any patents.

.: Links
Page of project
Official site
Wikipedia page

.: TEA

TEA operates on 64-bit blocks and uses a 128-bit key. Password must be declaration as pass[4], but string as array with 2 cell.

.: XTEA

Like TEA, XTEA is a 64-bit block Feistel network with a 128-bit key and a suggested 64 rounds. Several differences from TEA are apparent, including a somewhat more complex key-schedule and a rearrangement of the shifts, XORs, and additions.


.: Stocks
Length of the string must be even

stock tea_crypt_str(str[], key[4]) :
— crypt string with key
stock tea_decrypt_str(str[], key[4]) :
— decrypt string with key
stock tea_crypt(str[2], key[4]) :
— crypt 2 cell array with key
stock tea_decrypt(str[2], key[4]) :
— decrypt 2 cell array with key
stock xtea_crypt_str(str[], key[4]) :
— crypt string with key
stock xtea_decrypt_str(str[], key[4]) :
— decrypt string with key
stock xtea_crypt(str[2], key[4]) :
— crypt 2 cell array with key
stock xtea_decrypt(str[2], key[4]) :
— decrypt 2 cell array with key


.: Examples
Key creation

Key is composed from ordinary string of 16 characters length to packed array of 4 cell 4 bytes each.

PHP Code:

get_password_key() {
    new password[17], key[4];
    // get password string
    get_cvar_string("password", password, charsmax(password));
    // pack key
    new i = 0;
    while (password[i] != EOS) 
        key{i} = password[i++]

    return key
} 


Prepare string to crypt

If length is not even last odd character is not encrypted

PHP Code:

crypt_string(str[]) {
    new key[4] = get_password_key();
    new ch = EOS, len = strlen(str);

    // save last odd char
    if (len & 1)
        ch = str[--len];

    // replace last char to the end of the string
    str[len] = EOS;
    xtea_crypt_string(str, key);
    // restore last char
    str[len] = ch;
}

decrypt_string(str[]) {
    new key[4] = get_password_key();
    new ch = EOS, len = strlen(str);
    
    // save last odd char
    if (len & 1)
        ch = str[--len];

    // replace last char to the end of the string
    str[len] = EOS;
    xtea_decrypt_string(str, key);
    // restore last char
    str[len] = ch;
} 


[Seta00]

Sounds nice, but in your example, you are encrypting and decrypting with two different keys, how's that supposed to work?

[Zefir]

Why keys is different?

[Seta00]

Originally Posted by Zefir Why keys is different?

lol nevermind, I thought create_key was actually creating the key, I just remembered it's actually packing a value.

But if you change password between a encrypt/decrypt operation, things will go wrong. Keys should be bound 1-to-1 with encrypted strings, not global values.

[Zefir]

This is abstraction examples

In real plugin used global variables and some validators...

[xgam3r1]

you beat me to it, i have been working on an aio encryption include

[lucas_7_94]

i made this

#include <amxmodx>
#include <amxmisc>
#include <xtea.inc>

#define PLUGIN "New Plug-In"
#define VERSION "1.0"
#define AUTHOR "author"
public plugin_init() {
    register_plugin(PLUGIN, VERSION, AUTHOR)
    register_clcmd("say /asd", "clcmd_asd")
}

public clcmd_asd(id)
{
    new szInfo[370], data[9]
    new asd
    
    client_print(id, print_chat, "%s" , xtea_crypt("asd", data))
    client_print(id, print_chat, "called %s" , xtea_crypt_str("static-x", data))
    
}

but doesn't work , can any help me ?

[Exolent[jNr]]

It doesn't return a value.

new key[4];
key = create_key();

new string[] = "asdf";
xtea_crypt_str(string, key);

client_print(0, print_chat, "String: %s", string);

xtea_decrypt_str(string, key);

client_print(0, print_chat, "String: %s", string);

[lucas_7_94]

Originally Posted by Exolent[jNr] It doesn't return a value. new key[4]; key = create_key(); new string[] = "asdf"; xtea_crypt_str(string, key); client_print(0, print_chat, "String: %s", string); xtea_decrypt_str(string, key); client_print(0, print_chat, "String: %s", string);

i should go to test that NOW , thanks really thanks exolent.

I don't understand a one point , i should make these

create_key() { 
    new password[17], key[4]; 
    // get password string 
    get_cvar_string("password", password, charsmax(password)); 
    // pack key 
    new i = 0; 
    while (password[i] != EOS)  
        key{i} = password[i++] 

    return key 
}

and works ?

[AoD90]

Can u make xxtea for amxx?

http://pear.php.net/package/Crypt_XX...XXTEA.php.html