Hex Dump

A hex dump (or hexadecimal dump) is a textual representation of the binary data in a file, memory segment, or data stream.

Each byte (8 bits) is displayed in hexadecimal (base 16) form, allowing a binary value to be represented by two hexadecimal digits ranging from 00 to FF.

This representation is often accompanied by an ASCII column showing the corresponding printable characters, to facilitate the identification of readable text strings within the binary data.

The use of base 16 is particularly well-suited because it offers a direct correspondence with binary: a hexadecimal digit represents exactly 4 bits.

The hex dump is thus a fundamental tool in low-level computing, security, and reverse engineering. Using a hex dump allows you to:

— Analyze binary files (executables, images, databases) without relying on software capable of interpreting their format.

— Debug data corruption problems, for example, in the case of damaged files or network transmission errors.

— Understand the internal structure of files by identifying specific headers, metadata, or sections.

— Highlight hidden or undocumented information in the context of steganography or digital forensics.

— Compare binary files byte by byte to detect precise differences.

To interpret a hex dump:

— Locate the offset: the starting address, usually expressed in hexadecimal, indicates the position of the byte in the file or memory.

— Read the bytes: each pair of hexadecimal characters represents one byte.

— Examine the ASCII column: bytes corresponding to printable characters from the standard ASCII table (values 32 to 126) are displayed in plain text. Non-printable bytes are generally replaced by a period . to maintain visual alignment.

Converting a hex dump to a file involves reconstructing the original binary data from its hexadecimal representation.

The general principle is to remove all non-binary information (offsets, extra spaces, ASCII columns) to retain only the hexadecimal values representing the bytes.