A binary encoding method similar to UUencode, using 64 printable characters
Indices 0-63 correspond to characters: +-0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz
XXencode is a binary-to-text encoding method, similar to UUencode and Base64. It encodes 3 bytes into 4 printable characters, with each line starting with a length marker character. Commonly used in email transmission and early network environments.