hexlify

Hexlify is a term used to describe the conversion of binary data into a hexadecimal text representation. In this form, every input byte becomes two hexadecimal digits, producing a text-friendly version of the data. Hexadecimal representations are commonly used for displaying binary content, debugging, and transmitting binary data over text-based channels.

In Python, hexlify is implemented in the standard library's binascii module. The function hexlify(data) takes a bytes-like object and returns a bytes object containing the ASCII hex digits. For example, hexlify(b'\x00\x01\x02') yields b'000102'. Since the result is a bytes object in Python 3, it is often decoded to a string with .decode('ascii') if a text representation is needed. The digits are lowercase by default (0-9 and a-f).

Hexlify is typically the inverse of unhexlify, which converts a hex string back into binary data. For instance, unhexlify(b'deadbeef') returns the corresponding binary bytes b'\xde\xad\xbe\xef'. This pair is commonly used to safely transport or display binary data while preserving exact byte values.

Common use cases include representing cryptographic hashes, keys, or other binary content in logs, protocols, or user interfaces; preparing binary data for transmission over text-based channels; and debugging binary formats.

Other programming environments provide similar functionality under various names, offering the same underlying concept: converting between binary data and a hexadecimal textual form. See also: unhexlify, hex encoding, and binary-to-text encoding.