Doublehex

Doublehex is a term that appears in discussions of data encoding and hexadecimal representations. In a broad sense, it denotes a two-stage hexadecimal encoding of binary data, resulting in a textual representation that is longer than a standard hexadecimal string.

One common interpretation is hex-then-hex encoding. Here, binary data is first converted to a normal hex string, with two hex digits per byte. That hex string is then encoded again as hex by treating each ASCII character of the first hex string as a byte and converting those bytes to hexadecimal. For example, the input byte 0x2F yields the hex string "2F". The characters '2' and 'F' have ASCII codes 0x32 and 0x46, respectively, so the final representation is the hex sequence 32 46, i.e., the string "3246" in hex. In this scheme the length roughly doubles and the process is easily reversible.

Applications and compatibility: Doublehex is not a standardized encoding method and is mainly discussed in niche contexts such as obfuscated text representations, specialized data transport channels that tolerate only hexadecimal characters, or puzzle and challenge environments. It is invertible and deterministic, but its inefficiency and lack of standardization limit practical use.

Variants and related concepts: The idea of encoding a hex string again as hex can be extended or altered (for example, by repeating digits or applying alternative encodings). Related concepts include standard hex encoding, hex dumps, and hexadecimal escape sequences used in programming and data serialization. See also hex encoding, hex dump, and hexadecimal numeral systems.