- adler32 - Adler-32 is a hash algorithm like CRC-32, except that it is much faster and carries a slightly higher probability of collisions
- Blowfish - Blowfish is a 64-bit encryption algorithm, with a key length between 32 and 448 bits
- Bordeaux-FFT - Bordeaux-FFT is a fast, pure-Lisp implementation of Fast Fourier Transforms
- cl-base58 - This library implements the base58 encoding algorithm
- cl-buchberger - cl-buchberger is a Common Lisp implementation of Buchberger's algorithm for the computation of Gröbner bases
- cl-competitive - A code collection maintained mainly for competitive programming, and partly for just understanding algorithms
- CL-CTRNN - CL-CTRNN is a Common Lisp library for the simulation of Continuous-Time Recurrent Neural Networks (CTRNNs)
- cl-grnm - cl-grnm is an implementation of the Nelder-Mead and Grid Restrained Nelder-Mead nonlinear optimization algorithms
- CL-ID3 - CL-ID3 is a pure Common Lisp implementation of the well-known ID3 AI/data-mining algorithm
- cl-jointgen - CL-JOINTGEN is a Common Lisp implementation of the Joint Generation Algorithm for computing the dual of a monotone boolean function
- cl-satwrap - A thin generic SAT (propositional satisfiability problem) solver interface to your favorite “industrial-strength” SAT solver
- CLLIB - CLLIB is a varied collection of Common lisp tools and routines in CLOCC
- CRC-32 - A library to compute the CRC-32 algorithm that is described in RFC 1952
- decisiontree - This package provides an implementation of an algorithm that creates a decision tree
- floyd-warshall - floyd-warshall is a (very) preliminary library for Floyd-Warshall all-pairs shortest-path algorithm computations on weighted directed Graphs, written by Robert Goldman
- fuzzy-match - fuzzy-match is a library to fuzzy search an input string against a set of candidates
- Levenshtein - The Levenshtein Distance algorithm finds the minimum number of operations needed to transform one string into the other, where an operation is an insertion, deletion, or substitution of a single character
- Mersenne Twister - The Mersenne Twister is a pseudorandom number generation algorithm created by Makoto Matsumoto
- mk-string-metrics - This library implements efficient algorithms that calculate various string metrics in Common Lisp:
- mw-diff-sexp - A Common Lisp library to calculate a naive Levenshtein-like edit distance for s-expressions
- PorterStemmer - The Porter Stemmer is a stemming text algorithm by Martin Porter
- PRBS - Library of pseudo-random binary sequence generators (LFSR-2 and LFSR-4) and related functions in Common Lisp
- SAFER - SAFER (Secure And Fast Encryption Routine) is a block cipher that was first published in 1993, followed by later variants
- SEMI-PRECIOUS - SEMI-PRECIOUS is a library of algorithms/data structures
- SHA1 - Secure Hash Algorithm 1 (SHA1) is defined in RFC 3174, and therefore more-or-less counts as a protocol
- sha3 - This library is an implementation of the Secure Hash Algorithm 3 (SHA-3), also known as Keccak
- SimpSamp - SimpSamp is a statistics library for simple random sampling without replacement
- Soundex - The Soundex algorithm indexes words by their sound when pronounced in English, for example to account for differences in spelling
- ulimyhmpqs - ulimyhmpqs is an implementation of the Hypercube Multiple Polynomial Quadratic Sieve (HMPQS), an algorithm for the factorisation of large (up to about 110 digits, where the Number Field Sieve (NFS) algorithms become more efficient) integers
- XXTEA - XXTEA is an encryption algorithm, first introduced in 1998, which is relatively easy to implement

algorithm

Algorithms for doing various complicated things (mostly math-related).