The Libgcrypt Reference Manual

The Libgcrypt Library

This manual is for Libgcrypt (version 1.4.0, 6 December 2007), which is GNU's library of cryptographic building blocks.

Copyright © 2000, 2002, 2003, 2004, 2006, 2007 Free Software Foundation, Inc.

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 “Copying”.

• Introduction: What is Libgcrypt.
• Preparation: What you should do before using the library.
• Generalities: General library functions and data types.
• Handler Functions: Working with handler functions.
• Symmetric cryptography: How to use symmetric cryptography.
• Hashing: How to use hashing.
• Public Key cryptography (I): How to use public key cryptography.
• Public Key cryptography (II): How to use public key cryptography, alternatively.
• Random Numbers: How to work with random numbers.
• S-expressions: How to manage S-expressions.
• MPI library: How to work with multi-precision-integers.
• Prime numbers: How to use the Prime number related functions.
• Utilities: Utility functions.

Appendices

• Library Copying: The GNU Lesser General Public License says how you can copy and share Libgcrypt.
• Copying: The GNU General Public License says how you can copy and share some parts of Libgcrypt.

Indices

• Concept Index: Index of concepts and programs.
• Function and Data Index: Index of functions, variables and data types.

--- The Detailed Node Listing ---

Introduction

• Getting Started: How to use this manual.
• Features: A glance at Libgcrypt's features.
• Overview: Overview about the library.

Preparation

• Header: What header file you need to include.
• Building sources: How to build sources using the library.
• Building sources using Automake: How to build sources with the help of Automake.
• Initializing the library: How to initialize the library.
• Multi-Threading: How Libgcrypt can be used in a MT environment.

Generalities

• Controlling the library: Controlling Libgcrypt's behavior.
• Modules: Description of extension modules.
• Error Handling: Error codes and such.

Handler Functions

• Progress handler: Using a progress handler function.
• Allocation handler: Using special memory allocation functions.
• Error handler: Using error handler functions.
• Logging handler: Using a special logging function.

Symmetric cryptography

• Available ciphers: List of ciphers supported by the library.
• Cipher modules: How to work with cipher modules.
• Available cipher modes: List of cipher modes supported by the library.
• Working with cipher handles: How to perform operations related to cipher handles.
• General cipher functions: General cipher functions independent of cipher handles.

Hashing

• Available hash algorithms: List of hash algorithms supported by the library.
• Hash algorithm modules: How to work with hash algorithm modules.
• Working with hash algorithms: List of functions related to hashing.

Public Key cryptography (I)

• Used S-expressions: Introduction into the used S-expression.
• Available algorithms: Algorithms supported by the library.
• Public key modules: How to work with public key modules.
• Cryptographic Functions: Functions for performing the cryptographic actions.
• General public-key related Functions: General functions, not implementing any cryptography.

Public Key cryptography (II)

• Available asymmetric algorithms: List of algorithms supported by the library.
• Working with sets of data: How to work with sets of data.
• Working with handles: How to use handles.
• Working with keys: How to work with keys.
• Using cryptographic functions: How to perform cryptographic operations.
• Handle-independent functions: General functions independent of handles.

Random Numbers

• Quality of random numbers: Libgcrypt uses different quality levels.
• Retrieving random numbers: How to retrieve random numbers.

S-expressions

• Data types for S-expressions: Data types related with S-expressions.
• Working with S-expressions: How to work with S-expressions.

MPI library

• Data types: MPI related data types.
• Basic functions: First steps with MPI numbers.
• MPI formats: External representation of MPIs.
• Calculations: Performing MPI calculations.
• Comparisons: How to compare MPI values.
• Bit manipulations: How to access single bits of MPI values.
• Miscellaneous: Miscellaneous MPI functions.

Prime numbers

• Generation: Generation of new prime numbers.
• Checking: Checking if a given number is prime.

Utilities

• Memory allocation: Functions related with memory allocation.