Unix security-related software

'''''' is a computer program that calculates and verifies 128-bit MD5 hashes, as described in RFC 1321. The MD5 hash functions as a compact digital fingerprint of a file. As with all such hashing algorithms, there is theoretically an unlimited number of files that will have any given MD5 hash. However, it is very unlikely that any two non-identical files in the real world will have the same MD5 hash, unless they have been specifically created to do so.

rkhunter (Rootkit Hunter) is a Unix-based tool that scans for rootkits, backdoors and possible local exploits. It does this by comparing SHA-1 hashes of important files with known good ones in online databases, searching for default directories (of rootkits), wrong permissions, hidden files, suspicious strings in kernel modules, and special tests for Linux and FreeBSD. rkhunter is notable due to its inclusion in popular operating systems (Fedora, Debian, etc.)

open source security software

chkrootkit (Check Rootkit) is a Unix-based program intended to help system administrators check their system for local signs of known rootkits. It is a shell script using common UNIX/Linux tools like the strings and grep commands to search core system programs for signatures and for comparing a traversal of the /proc filesystem with the output of the ps (process status) command to look for discrepancies.

' is a computer program that calculates and verifies SHA-1 hashes. It is commonly used to verify the integrity of files. It (or a variant) is installed by default on most Linux distributions. Typically distributed alongside are , , and , which use a specific SHA-2 hash function and ', which uses the BLAKE2 cryptographic hash function.

software tools for forensics analysis on volume and filesystem data

Unix command to securely delete files and devices