Packing

Packing is a technique used to compress and disguise the code, making it difficult to understand and reverse-engineer. It's a form of Obfuscation (KB)|obfuscation that goes beyond simple JavaScript Minification|minification.

The original JavaScript code is compressed, reducing its size. This often involves removing unnecessary characters (like whitespace and comments), as in minification, but can also include more advanced transformations.

The compressed code is then encoded into a non-standard format. This could be a base64 encoding or any other custom encoding mechanism. The objective is to make the code look like a nonsensical string of characters, which is hard to interpret.

The encoded string is embedded within a wrapper function. This function is responsible for decoding the string back into JavaScript code at runtime.

When the JavaScript file is loaded by a web browser, the wrapper function executes, decodes the packed code, and then evaluates it using methods like eval() to run the original JavaScript.

The (p,a,c,k,e,d) function, often seen in packed JavaScript code, is a common pattern used in a specific JavaScript packing technique. This function is part of a method to obfuscate and compress the code.

The letters (p,a,c,k,e,d) don't have any special meaning themselves; they are just parameter names used in this specific packing algorithm.

• p: Usually a string containing parts of the original code.
• a, c, k: These parameters are typically used in the function's algorithm to map, replace, or decode the packed code.
• e: Sometimes used as a placeholder in the function's logic.
• d: Often an empty object or another placeholder.