Alphanumeric codeIn computer science (or more likely, in computer underground terminology) alphanumeric code is machine code that is written entirely in readable ASCII-letters such as "a"-"z", "A"-"Z", "1"-"9", "#", "!", "@", etc.
This is possible to do with a (very) good understanding of the assembly language for the specific computer that the code is intended for.
This code is used by crackerss with the intent of fooling applications, such as Web forms, into accepting code used for exploits. Typically, such exploits involve buffer overflows.