xtutils
Version:
Thuku's assorted general purpose typescript/javascript library.
41 lines • 1.36 kB
JavaScript
;
Object.defineProperty(exports, "__esModule", { value: true });
exports._rc4 = void 0;
/**
* RC4 encrypt/decrypt text value
*
* @param text - parse text
* @param key - cypher key (default: `'alohomora'`)
* @returns `string`
*/
function _rc4(input, pass) {
const is_buffer = Buffer.isBuffer(input);
const data = is_buffer ? input : Buffer.from(String(input ?? ''), 'binary');
if (!data.length)
return (is_buffer ? Buffer.from('') : '');
let S = Array.from({ length: 256 }, (_, i) => i);
let j = 0;
pass = String(pass ?? 'alohomora');
const key = Array.from(pass).map(c => c.charCodeAt(0));
for (let i = 0; i < 256; i++) {
j = (j + S[i] + key[i % key.length]) % 256;
[S[i], S[j]] = [S[j], S[i]];
}
let i = 0, k = 0, result = '';
const buffer = Buffer.from(new Uint8Array(data.length));
for (let n = 0; n < data.length; n++) {
i = (i + 1) % 256;
k = (k + S[i]) % 256;
[S[i], S[k]] = [S[k], S[i]];
const key_stream = S[(S[i] + S[k]) % 256];
const transformed_byte = data[n] ^ key_stream;
if (is_buffer)
buffer[n] = transformed_byte;
else
result += String.fromCharCode(transformed_byte);
}
return (is_buffer ? buffer : result);
}
exports._rc4 = _rc4;
;
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