The Libgcrypt Library

This manual is for Libgcrypt version 1.10.1 and was last updated 28 March 2022. Libgcrypt is GNU’s library of cryptographic building blocks.

Permission is granted to copy, distribute and/or modify this document under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. The text of the license can be found in the section entitled “GNU General Public License”.

1 Introduction
- 1.1 Getting Started
- 1.2 Features
- 1.3 Overview
2 Preparation
- 2.1 Header
- 2.2 Building sources
- 2.3 Building sources using Automake
- 2.4 Initializing the library
- 2.5 Multi-Threading
- 2.6 How to enable the FIPS mode
- 2.7 How to disable the FIPS mode
- 2.8 How to disable hardware features
3 Generalities
- 3.1 Controlling the library
- 3.2 Error Handling
4 Handler Functions
- 4.1 Progress handler
- 4.2 Allocation handler
- 4.3 Error handler
- 4.4 Logging handler
5 Symmetric cryptography
- 5.1 Available ciphers
- 5.2 Available cipher modes
- 5.3 Working with cipher handles
- 5.4 General cipher functions
6 Public Key cryptography
- 6.1 Available algorithms
- 6.2 Used S-expressions
- 6.3 Cryptographic Functions
- 6.4 Dedicated functions for elliptic curves.
- 6.5 General public-key related Functions
7 Hashing
- 7.1 Available hash algorithms
- 7.2 Working with hash algorithms
8 Message Authentication Codes
- 8.1 Available MAC algorithms
- 8.2 Working with MAC algorithms
9 Key Derivation
10 Random Numbers
- 10.1 Quality of random numbers
- 10.2 Retrieving random numbers
11 S-expressions
- 11.1 Data types for S-expressions
- 11.2 Working with S-expressions
12 MPI library
- 12.1 Data types
- 12.2 Basic functions
- 12.3 MPI formats
- 12.4 Calculations
- 12.5 Comparisons
- 12.6 Bit manipulations
- 12.7 EC functions
- 12.8 Miscellaneous
13 Prime numbers
- 13.1 Generation
- 13.2 Checking
14 Utilities
- 14.1 Memory allocation
- 14.2 Context management
- 14.3 Buffer description
- 14.4 How to check Libgcrypt’s configuration.
15 Tools
- 15.1 A HMAC-SHA-256 tool
16 Configuration files and environment variables
17 Architecture
- 17.1 Public-Key Architecture
- 17.2 Symmetric Encryption Subsystem Architecture
- 17.3 Hashing and MACing Subsystem Architecture
- 17.4 Multi-Precision-Integer Subsystem Architecture
- 17.5 Prime-Number-Generator Subsystem Architecture
- 17.6 Random-Number Subsystem Architecture
  - 17.6.1 Description of the CSPRNG
  - 17.6.2 Description of the DRBG
Appendix A Description of the Self-Tests
- A.1 Power-Up Tests
- A.2 Conditional Tests
- A.3 Application Requested Tests
Appendix B Description of the FIPS Mode
- B.1 Restrictions in FIPS Mode
- B.2 FIPS Finite State Machine
- B.3 FIPS Miscellaneous Information
GNU Lesser General Public License
GNU General Public License
List of Figures and Tables
Concept Index
Function and Data Index

The Libgcrypt Reference Manual

The Libgcrypt Library

Table of Contents

Short Table of Contents