- You may be looking for Character encoding.
In general, in computing, an alphanumeric code is a series of letters and numbers (hence the name) which are written in a form that can be processed by a computer.
More specifically, in computer underground terminology, alphanumeric code is machine code that is written so that it assembles into entirely readable ASCII characters such as "a"-"z", "A"-"Z", "1"-"9", "#", "!", "@", and so on.
Writing alphanumeric code requires a good understanding of the instruction set architecture of the machine on which the code is to be executed.
This code is used by crackers with the intent of fooling applications, such as Web forms, into accepting exploit code ("shellcode"). Typically, such exploits involve buffer overflows.
Sometimes, alphanumeric code could also be used when the programmer needs to write a program but has access only to a text editor — no compiler, assembler, or hex editor.
External links
- ALPHA2, an alphanumeric shellcode encoder: Utility to encode normal machine code into alphanumeric (upper-case or mixed-case) ASCII or Unicode text
- Shellcoding for Linux and Windows — Printable Shellcode: Explanation and tutorial