Xapian is a highly adaptable toolkit which allows developers to easily add advanced indexing and search facilities to their own applications. It supports the Probabilistic Information Retrieval model and also supports a rich set of boolean query operators.

Ugrep is a ultra fast searcher of file systems, text and binary files, source code, archives, compressed files, documents, and more.

While still being compatible with the standard GNU/BSD grep command-line options, ugrep supports fuzzy search as well as structured and (adjustable) colored output, piped through "less" for pagination. An interactive query UI allows refinement and has a built-in help (press F1). Ugrep implements multi-threaded and other techniques to speed up search, pattern-matching and decompression. Many pre-defined regexps ease searching e.g. C typdefs or XML attributes. Results can be output in several structured or self-defined formats.

FSearch is a fast file search utility, inspired by Everything Search Engine. It is written in C and based on GTK3.

libtocc is the engine of the Tocc project, a tag-based file management system. The goal of Tocc is to provide a better system for classifying files that is more flexible than classic file systems that are based on a tree of files and directories.

Hyper Estraier can be used to integrate full-text search into applications, using either the provided command line and CGI interfaces, or a C API.

GNU Bool is a utility to perform text searches on files using Boolean expressions. For example, a search for "hello AND world" would return a file containing the phrase "Hello, world!". It supports both AND and OR statements, as well as the NEAR statement to search for the occurrence of words in close proximity to each other. It handles context gracefully, accounting for new lines and paragraph changes. It also has robust support for parsing HTML files.

Search::Xapian wraps most methods of most Xapian classes. The missing classes and methods should be added in the future. It also provides a simplified, more 'perlish' interface to some common operations.

Omega is a search application built on Xapian. It provides indexers and a CGI web search frontend.

Swish-e is Simple Web Indexing System for Humans - Enhanced. Swish-e can quickly and easily index directories of files or remote web sites and search the generated indexes.

Tocc is a tag-based file management system. This package contains the command line tool for interacting with libtocc.

Recoll finds documents based on their contents as well as their file names. It can search most document formats, but you may need external applications for text extraction. It can reach any storage place: files, archive members, email attachments, transparently handling decompression.

Dataparksearch is a full featured web search engine. It has support for HTTP, HTTPS, ftp (passive mode), NNTP and news URL schemes, and other URL schemes with external parsers. It can tweak URLs with session IDs and other weird formats, including some JavaScript link decoding. Options to query with all words, all words near to each others, any words, or boolean queries. A subset of VQL (Verity Query Language) is supported.

mlocate is a locate/updatedb implementation. The m stands for "merging": updatedb reuses the existing database to avoid rereading most of the file system, which makes it faster and does not trash the system caches as much. The locate(1) utility is intended to be completely compatible with slocate, and attempts to be compatible to GNU locate when it does not conflict with slocate compatibility.

This package provides a PC/SC IFD handler implementation for devices compliant with the CCID and ICCD protocols. It supports a wide range of readers and is needed to communicate with such devices through the pcscd resource manager.

SoftHSM 2 is a software implementation of a generic cryptographic device with a PKCS #11 Cryptographic Token Interface.

This is a C library that implements the server-side of the Universal 2nd Factor (U2F) protocol. More precisely, it provides an API for generating the JSON blobs required by U2F devices to perform the U2F Registration and U2F Authentication operations, and functionality for verifying the cryptographic operations.

This package provides a module implementing PAM over U2F, providing an easy way to integrate the YubiKey (or other U2F compliant authenticators) into your existing infrastructure.

This package provides GUI tool that interfaces with Nitrokey Pro v0.7/v0.8 and Nitrokey Storage devices.

Libu2f-host provides a C library and command-line tool that implements the host-side of the Universal 2nd Factor (U2F) protocol. There are APIs to talk to a U2F device and perform the U2F Register and U2F Authenticate operations.

This package provides library to encode/decode base64, base64url, base32, base32hex and hex.

This package includes the IFD driver for the cyberJack contactless (RFID) and contact USB chipcard readers.

This Python library provides functionality for communicating with a Fast IDentity Online (FIDO) device over Universal Serial Bus (USB) as well as verifying attestation and assertion signatures. It aims to support the FIDO Universal 2nd Factor (U2F) and FIDO 2.0 protocols for communicating with a USB authenticator via the Client-to-Authenticator Protocol (CTAP 1 and 2). In addition to this low-level device access, classes defined in the fido2.client and fido2.server modules implement higher level operations which are useful when interfacing with an Authenticator, or when implementing a Relying Party.

Pkcs11-helper is a library that simplifies the interaction with PKCS#11 providers for end-user applications. PKCS#11 is published standard. PKCS#11 is the de-facto standard to access cryptographic devices

OpenSC is a set of software tools and libraries to work with smart cards, with the focus on smart cards with cryptographic capabilities. OpenSC facilitate the use of smart cards in security applications such as authentication, encryption and digital signatures. OpenSC implements the PKCS #15 standard and the PKCS #11 API.