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sqlcipher/sqlcipher: SQLCipher is a standalone fork of SQLite that adds 256 bit AES encryption of database files and other security features.

SQLCipher is a standalone fork of the SQLite database library that adds 256 bit AES encryption of database files and other security features like:

SQLCipher is based on SQLite and stable upstream release features are periodically integrated. While SQLCipher is maintained as a separate version of the source tree, the project minimizes alterations to core SQLite code whenever possible.

SQLCipher is maintained by Zetetic, LLC, and additional information and documentation is available on the official SQLCipher site.

SQLCipher maintains database format compatibility within the same major version number so an application on any platform can open databases created by any other application provided the major version of SQLCipher is the same between them. However, major version updates (e.g. from 3.x to 4.x) often include changes to default settings. This means that newer major versions of SQLCipher will not open databases created by older versions without using special settings. For example, SQLCipher 4 introduces many new performance and security enhancements. The new default algorithms, increased KDF iterations, and larger page size mean that SQLCipher 4 will not open databases created by SQLCipher 1.x, 2.x, or 3.x by default. Instead, an application would either need to migrate the older databases to use the new format or enable a special backwards-compatibility mode. The available options are described in SQLCipher's upgrade documentation.

SQLCipher is also compatible with standard SQLite databases. When a key is not provided, SQLCipher will behave just like the standard SQLite library. It is also possible to convert from a plaintext database (standard SQLite) to an encrypted SQLCipher database using ATTACH and the sqlcipher_export() convenience function.

The SQLCipher team welcomes contributions to the core library. All contributions including pull requests and patches should be based on the prerelease branch, and must be accompanied by a contributor agreement. We strongly encourage discussion of the proposed change prior to development and submission.

Building SQLCipher is similar to compiling a regular version of SQLite from source, with a few small exceptions. You must:

  1. define SQLITE_HAS_CODEC
  2. define SQLITE_TEMP_STORE=2 or SQLITE_TEMP_STORE=3 (or use configure's --with-tempstore=yes option)
  3. define SQLITE_EXTRA_INIT=sqlcipher_extra_init and SQLITE_EXTRA_SHUTDOWN=sqlcipher_extra_shutdown
  4. define SQLITE_THREADSAFE to 1 or 2 (enabled automatically by configure)
  5. compile and link with a supported cryptographic provider (OpenSSL, LibTomCrypt, CommonCrypto/Security.framework, or NSS)

The following examples demonstrate use of OpenSSL, which is a readily available provider on most Unix-like systems. Note that, in this example, --with-tempstore=yes is setting SQLITE_TEMP_STORE=2 for the build, and SQLITE_THREADSAFE has a default value of 1.

$ ./configure --with-tempstore=yes CFLAGS="-DSQLITE_HAS_CODEC -DSQLITE_EXTRA_INIT=sqlcipher_extra_init -DSQLITE_EXTRA_SHUTDOWN=sqlcipher_extra_shutdown" \
	LDFLAGS="-lcrypto"
$ make

The full SQLite test suite will not complete successfully when using SQLCipher. In some cases encryption interferes with low-level tests that require access to database file data or features which are unsupported by SQLCipher. Those tests that are intended to support encryption are intended for non-SQLCipher implementations. In addition, because SQLite tests are not always isolated, if one test fails it can trigger a domino effect with other failures in later steps.

As a result, the SQLCipher package includes it's own independent tests that exercise and verify the core functionality of the SQLCipher extensions. This test suite is intended to provide an abbreviated verification of SQLCipher's internal logic; it does not perform an exhaustive test of the SQLite database system as a whole or verify functionality on specific platforms. Because SQLCipher is based on stable upstream builds of SQLite, it is considered a basic assumption that the core SQLite library code is operating properly (the SQLite core is almost untouched in SQLCipher). Thus, the additional SQLCipher-specific test provide the requisite verification that the library is operating as expected with SQLCipher's security features enabled.

To run SQLCipher specific tests, configure as described here and run the following to execute the tests and receive a report of the results:

$ ./configure --with-tempstore=yes --enable-fts5 CFLAGS="-DSQLITE_HAS_CODEC -DSQLITE_EXTRA_INIT=sqlcipher_extra_init -DSQLITE_EXTRA_SHUTDOWN=sqlcipher_extra_shutdown -DSQLCIPHER_TEST" \
	LDFLAGS="-lcrypto"
$ make testfixture
$ ./testfixture test/sqlcipher.test

To specify an encryption passphrase for the database via the SQL interface you use a PRAGMA. The passphrase you enter is passed through PBKDF2 key derivation to obtain the encryption key for the database

PRAGMA key = 'passphrase';

Alternately, you can specify an exact byte sequence using a blob literal. If you use this method it is your responsibility to ensure that the data you provide is a 64 character hex string, which will be converted directly to 32 bytes (256 bits) of key data without key derivation.

PRAGMA key = "x'2DD29CA851E7B56E4697B0E1F08507293D761A05CE4D1B628663F411A8086D99'";

To encrypt a database programmatically you can use the sqlite3_key function. The data provided in pKey is converted to an encryption key according to the same rules as PRAGMA key.

int sqlite3_key(sqlite3 *db, const void *pKey, int nKey);

PRAGMA key or sqlite3_key should be called as the first operation when a database is open.

To change the encryption passphrase for an existing database you may use the rekey PRAGMA after you've supplied the correct database password;

PRAGMA key = 'passphrase'; -- start with the existing database passphrase
PRAGMA rekey = 'new-passphrase'; -- rekey will reencrypt with the new passphrase

The hex rekey pragma may be used to rekey to a specific binary value

PRAGMA rekey = "x'2DD29CA851E7B56E4697B0E1F08507293D761A05CE4D1B628663F411A8086D99'";

This can be accomplished programmatically by using sqlite3_rekey;

sqlite3_rekey(sqlite3 *db, const void *pKey, int nKey)

The primary source for complete documentation (design, API, platforms, usage) is the SQLCipher website:

https://www.zetetic.net/sqlcipher/documentation

The primary avenue for support and discussions is the SQLCipher discuss site:

https://discuss.zetetic.net/c/sqlcipher

Issues or support questions on using SQLCipher should be entered into the GitHub Issue tracker:

https://github.com/sqlcipher/sqlcipher/issues

Please DO NOT post issues, support questions, or other problems to blog posts about SQLCipher as we do not monitor them frequently.

If you are using SQLCipher in your own software please let us know at support@zetetic.net!

Community Edition Open Source License

Copyright (c) 2025, ZETETIC LLC All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: * Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. * Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. * Neither the name of the ZETETIC LLC nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY ZETETIC LLC ''AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL ZETETIC LLC BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

This repository contains the complete source code for the SQLite database engine, including many test scripts. However, other test scripts and most of the documentation are managed separately.

See the on-line documentation for more information about what SQLite is and how it works from a user's perspective. This README file is about the source code that goes into building SQLite, not about how SQLite is used.

SQLite sources are managed using Fossil, a distributed version control system that was specifically designed and written to support SQLite development. The Fossil repository contains the urtext.

If you are reading this on GitHub or some other Git repository or service, then you are looking at a mirror. The names of check-ins and other artifacts in a Git mirror are different from the official names for those objects. The official names for check-ins are found in a footer on the check-in comment for authorized mirrors. The official check-in name can also be seen in the manifest.uuid file in the root of the tree. Always use the official name, not the Git-name, when communicating about an SQLite check-in.

If you pulled your SQLite source code from a secondary source and want to verify its integrity, there are hints on how to do that in the Verifying Code Authenticity section below.

Contacting The SQLite Developers

The preferred way to ask questions or make comments about SQLite or to report bugs against SQLite is to visit the SQLite Forum at https://sqlite.org/forum/. Anonymous postings are permitted.

If you think you have found a bug that has security implications and you do not want to report it on the public forum, you can send a private email to drh at sqlite dot org.

The SQLite source code is in the public domain. See https://sqlite.org/copyright.html for details.

Because SQLite is in the public domain, we do not normally accept pull requests, because if we did take a pull request, the changes in that pull request might carry a copyright and the SQLite source code would then no longer be fully in the public domain.

Obtaining The SQLite Source Code

If you do not want to use Fossil, you can download tarballs or ZIP archives or SQLite archives as follows:

To access sources directly using Fossil, first install Fossil version 2.0 or later. Source tarballs and precompiled binaries available at https://fossil-scm.org/home/uv/download.html. Fossil is a stand-alone program. To install, simply download or build the single executable file and put that file someplace on your $PATH. Then run commands like this:

    mkdir -p ~/sqlite
    cd ~/sqlite
    fossil open https://sqlite.org/src

The "fossil open" command will take two or three minutes. Afterwards, you can do fast, bandwidth-efficient updates to the whatever versions of SQLite you like. Some examples:

    fossil update trunk             ;# latest trunk check-in
    fossil update release           ;# latest official release
    fossil update trunk:2024-01-01  ;# First trunk check-in after 2024-01-01
    fossil update version-3.39.0    ;# Version 3.39.0

Or type "fossil ui" to get a web-based user interface.

Compiling for Unix-like systems

First create a directory in which to place the build products. It is recommended, but not required, that the build directory be separate from the source directory. Cd into the build directory and then from the build directory run the configure script found at the root of the source tree. Then run "make".

For example:

    apt install gcc make tcl-dev  ;#  Make sure you have all the necessary build tools
    tar xzf sqlite.tar.gz         ;#  Unpack the source tree into "sqlite"
    mkdir bld                     ;#  Build will occur in a sibling directory
    cd bld                        ;#  Change to the build directory
    ../sqlite/configure           ;#  Run the configure script
    make sqlite3                  ;#  Builds the "sqlite3" command-line tool
    make sqlite3.c                ;#  Build the "amalgamation" source file
    make sqldiff                  ;#  Builds the "sqldiff" command-line tool
    # Makefile targets below this point require tcl-dev
    make tclextension-install     ;#  Build and install the SQLite TCL extension
    make devtest                  ;#  Run development tests
    make releasetest              ;#  Run full release tests
    make sqlite3_analyzer         ;#  Builds the "sqlite3_analyzer" tool

See the makefile for additional targets. For debugging builds, the core developers typically run "configure" with options like this:

    ../sqlite/configure --enable-all --enable-debug CFLAGS='-O0 -g'

For release builds, the core developers usually do:

    ../sqlite/configure --enable-all

Almost all makefile targets require a "tclsh" TCL interpreter version 8.6 or later. The "tclextension-install" target and the test targets that follow all require TCL development libraries too. ("apt install tcl-dev"). It is helpful, but is not required, to install the SQLite TCL extension (the "tclextension-install" target) prior to running tests. The "releasetest" target has additional requiremenst, such as "valgrind".

On "make" command-lines, one can add "OPTIONS=..." to specify additional compile-time options over and above those set by ./configure. For example, to compile with the SQLITE_OMIT_DEPRECATED compile-time option, one could say:

    ./configure --enable-all
    make OPTIONS=-DSQLITE_OMIT_DEPRECATED sqlite3

The configure script uses autoconf 2.61 and libtool. If the configure script does not work out for you, there is a generic makefile named "Makefile.linux-gcc" in the top directory of the source tree that you can copy and edit to suit your needs. Comments on the generic makefile show what changes are needed.

Compiling for Windows Using MSVC

On Windows, everything can be compiled with MSVC. You will also need a working installation of TCL. See the compile-for-windows.md document for additional information about how to install MSVC and TCL and configure your build environment.

If you want to run tests, you need to let SQLite know the location of your TCL library, using a command like this:

SQLite uses "tclsh.exe" as part of the build process, and so that program will need to be somewhere on your %PATH%. SQLite itself does not contain any TCL code, but it does use TCL to help with the build process and to run tests. You may need to install TCL development libraries in order to successfully complete some makefile targets. It is helpful, but is not required, to install the SQLite TCL extension (the "tclextension-install" target) prior to running tests.

Build using Makefile.msc. Example:

    nmake /f Makefile.msc sqlite3.exe
    nmake /f Makefile.msc sqlite3.c
    nmake /f Makefile.msc sqldiff.exe
    # Makefile targets below this point require TCL development libraries
    nmake /f Makefile.msc tclextension-install
    nmake /f Makefile.msc devtest
    nmake /f Makefile.msc releasetest
    nmake /f Makefile.msc sqlite3_analyzer.exe

There are many other makefile targets. See comments in Makefile.msc for details.

As with the unix Makefile, the OPTIONS=... argument can be passed on the nmake command-line to enable new compile-time options. For example:

    nmake /f Makefile.msc OPTIONS=-DSQLITE_OMIT_DEPRECATED sqlite3.exe
Generated Source Code Files

Several of the C-language source files used by SQLite are generated from other sources rather than being typed in manually by a programmer. This section will summarize those automatically-generated files. To create all of the automatically-generated files, simply run "make target_source". The "target_source" make target will create a subdirectory "tsrc/" and fill it with all the source files needed to build SQLite, both manually-edited files and automatically-generated files.

The SQLite interface is defined by the sqlite3.h header file, which is generated from src/sqlite.h.in, ./manifest.uuid, and ./VERSION. The Tcl script at tool/mksqlite3h.tcl does the conversion. The manifest.uuid file contains the SHA3 hash of the particular check-in and is used to generate the SQLITE_SOURCE_ID macro. The VERSION file contains the current SQLite version number. The sqlite3.h header is really just a copy of src/sqlite.h.in with the source-id and version number inserted at just the right spots. Note that comment text in the sqlite3.h file is used to generate much of the SQLite API documentation. The Tcl scripts used to generate that documentation are in a separate source repository.

The SQL language parser is parse.c which is generated from a grammar in the src/parse.y file. The conversion of "parse.y" into "parse.c" is done by the lemon LALR(1) parser generator. The source code for lemon is at tool/lemon.c. Lemon uses the tool/lempar.c file as a template for generating its parser. Lemon also generates the parse.h header file, at the same time it generates parse.c.

The opcodes.h header file contains macros that define the numbers corresponding to opcodes in the "VDBE" virtual machine. The opcodes.h file is generated by scanning the src/vdbe.c source file. The Tcl script at ./mkopcodeh.tcl does this scan and generates opcodes.h. A second Tcl script, ./mkopcodec.tcl, then scans opcodes.h to generate the opcodes.c source file, which contains a reverse mapping from opcode-number to opcode-name that is used for EXPLAIN output.

The keywordhash.h header file contains the definition of a hash table that maps SQL language keywords (ex: "CREATE", "SELECT", "INDEX", etc.) into the numeric codes used by the parse.c parser. The keywordhash.h file is generated by a C-language program at tool mkkeywordhash.c.

The pragma.h header file contains various definitions used to parse and implement the PRAGMA statements. The header is generated by a script tool/mkpragmatab.tcl. If you want to add a new PRAGMA, edit the tool/mkpragmatab.tcl file to insert the information needed by the parser for your new PRAGMA, then run the script to regenerate the pragma.h header file.

All of the individual C source code and header files (both manually-edited and automatically-generated) can be combined into a single big source file sqlite3.c called "the amalgamation". The amalgamation is the recommended way of using SQLite in a larger application. Combining all individual source code files into a single big source code file allows the C compiler to perform more cross-procedure analysis and generate better code. SQLite runs about 5% faster when compiled from the amalgamation versus when compiled from individual source files.

The amalgamation is generated from the tool/mksqlite3c.tcl Tcl script. First, all of the individual source files must be gathered into the tsrc/ subdirectory (using the equivalent of "make target_source") then the tool/mksqlite3c.tcl script is run to copy them all together in just the right order while resolving internal "#include" references.

The amalgamation source file is more than 200K lines long. Some symbolic debuggers (most notably MSVC) are unable to deal with files longer than 64K lines. To work around this, a separate Tcl script, tool/split-sqlite3c.tcl, can be run on the amalgamation to break it up into a single small C file called sqlite3-all.c that does #include on about seven other files named sqlite3-1.c, sqlite3-2.c, ..., sqlite3-7.c. In this way, all of the source code is contained within a single translation unit so that the compiler can do extra cross-procedure optimization, but no individual source file exceeds 32K lines in length.

SQLite is modular in design. See the architectural description for details. Other documents that are useful in helping to understand how SQLite works include the file format description, the virtual machine that runs prepared statements, the description of how transactions work, and the overview of the query planner.

Decades of effort have gone into optimizing SQLite, both for small size and high performance. And optimizations tend to result in complex code. So there is a lot of complexity in the current SQLite implementation. It will not be the easiest library in the world to hack.

There are many other source files. Each has a succinct header comment that describes its purpose and role within the larger system.

Verifying Code Authenticity

The manifest file at the root directory of the source tree contains either a SHA3-256 hash or a SHA1 hash for every source file in the repository. The name of the version of the entire source tree is just the SHA3-256 hash of the manifest file itself, possibly with the last line of that file omitted if the last line begins with "# Remove this line". The manifest.uuid file should contain the SHA3-256 hash of the manifest file. If all of the above hash comparisons are correct, then you can be confident that your source tree is authentic and unadulterated. Details on the format for the manifest files are available on the Fossil website.

The process of checking source code authenticity is automated by the makefile:

make verify-source

Or on windows:

nmake /f Makefile.msc verify-source

Using the makefile to verify source integrity is good for detecting accidental changes to the source tree, but malicious changes could be hidden by also modifying the makefiles.

The main SQLite website is https://sqlite.org/ with geographically distributed backups at https://www2.sqlite.org/ and https://www3.sqlite.org/.

Contact the SQLite developers through the SQLite Forum. In an emergency, you can send private email to the lead developer at drh at sqlite dot org.

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