4 This document describes installation on all supported operating
5 systems (the Unix/Linux family, including macOS), OpenVMS,
11 - [Prerequisites](#prerequisites)
12 - [Notational Conventions](#notational-conventions)
13 - [Quick Installation Guide](#quick-installation-guide)
14 - [Building OpenSSL](#building-openssl)
15 - [Installing OpenSSL](#installing-openssl)
16 - [Configuration Options](#configuration-options)
17 - [API Level](#api-level)
18 - [Cross Compile Prefix](#cross-compile-prefix)
19 - [Build Type](#build-type)
20 - [Directories](#directories)
21 - [Compiler Warnings](#compiler-warnings)
22 - [Compression Algorithm Flags](#compression-algorithm-flags)
23 - [Seeding the Random Generator](#seeding-the-random-generator)
24 - [Setting the FIPS HMAC key](#setting-the-FIPS-HMAC-key)
25 - [Enable and Disable Features](#enable-and-disable-features)
26 - [Displaying configuration data](#displaying-configuration-data)
27 - [Installation Steps in Detail](#installation-steps-in-detail)
28 - [Configure](#configure-openssl)
29 - [Build](#build-openssl)
30 - [Test](#test-openssl)
31 - [Install](#install-openssl)
32 - [Advanced Build Options](#advanced-build-options)
33 - [Environment Variables](#environment-variables)
34 - [Makefile Targets](#makefile-targets)
35 - [Running Selected Tests](#running-selected-tests)
36 - [Troubleshooting](#troubleshooting)
37 - [Configuration Problems](#configuration-problems)
38 - [Build Failures](#build-failures)
39 - [Test Failures](#test-failures)
41 - [Notes on multi-threading](#notes-on-multi-threading)
42 - [Notes on shared libraries](#notes-on-shared-libraries)
43 - [Notes on random number generation](#notes-on-random-number-generation)
44 - [Notes on assembler modules compilation](#notes-on-assembler-modules-compilation)
49 To install OpenSSL, you will need:
51 * A "make" implementation
52 * Perl 5 with core modules (please read [NOTES-PERL.md](NOTES-PERL.md))
53 * The Perl module `Text::Template` (please read [NOTES-PERL.md](NOTES-PERL.md))
55 * a development environment in the form of development libraries and C
57 * a supported operating system
59 For additional platform specific requirements, solutions to specific
60 issues and other details, please read one of these:
62 * [Notes for UNIX-like platforms](NOTES-UNIX.md)
63 * [Notes for Android platforms](NOTES-ANDROID.md)
64 * [Notes for Windows platforms](NOTES-WINDOWS.md)
65 * [Notes for the DOS platform with DJGPP](NOTES-DJGPP.md)
66 * [Notes for the OpenVMS platform](NOTES-VMS.md)
67 * [Notes on Perl](NOTES-PERL.md)
68 * [Notes on Valgrind](NOTES-VALGRIND.md)
70 Notational conventions
71 ======================
73 Throughout this document, we use the following conventions.
78 Any line starting with a dollar sign is a command line.
82 The dollar sign indicates the shell prompt and is not to be entered as
88 Several words in curly braces separated by pipe characters indicate a
89 **mandatory choice**, to be replaced with one of the given words.
92 $ echo { WORD1 | WORD2 | WORD3 }
94 represents one of the following three commands
102 One or several words in square brackets separated by pipe characters
103 denote an **optional choice**. It is similar to the mandatory choice,
104 but it can also be omitted entirely.
108 $ echo [ WORD1 | WORD2 | WORD3 ]
110 represents one of the four commands
123 **Optional Arguments** are enclosed in square brackets.
127 A trailing ellipsis means that more than one could be specified.
129 Quick Installation Guide
130 ========================
132 If you just want to get OpenSSL installed without bothering too much
133 about the details, here is the short version of how to build and install
134 OpenSSL. If any of the following steps fails, please consult the
135 [Installation in Detail](#installation-steps-in-detail) section below.
140 Use the following commands to configure, build and test OpenSSL.
141 The testing is optional, but recommended if you intend to install
142 OpenSSL for production use.
144 ### Unix / Linux / macOS
152 Use the following commands to build OpenSSL:
160 If you are using Visual Studio, open a Developer Command Prompt and
161 issue the following commands to build OpenSSL.
167 As mentioned in the [Choices](#choices) section, you need to pick one
168 of the four Configure targets in the first command.
170 Most likely you will be using the `VC-WIN64A`/`VC-WIN64A-HYBRIDCRT` target for
171 64bit Windows binaries (AMD64) or `VC-WIN32`/`VC-WIN32-HYBRIDCRT` for 32bit
172 Windows binaries (X86).
173 The other two options are `VC-WIN64I` (Intel IA64, Itanium) and
174 `VC-CE` (Windows CE) are rather uncommon nowadays.
179 The following commands will install OpenSSL to a default system location.
181 **Danger Zone:** even if you are impatient, please read the following two
182 paragraphs carefully before you install OpenSSL.
184 For security reasons the default system location is by default not writable
185 for unprivileged users. So for the final installation step administrative
186 privileges are required. The default system location and the procedure to
187 obtain administrative privileges depends on the operating system.
188 It is recommended to compile and test OpenSSL with normal user privileges
189 and use administrative privileges only for the final installation step.
191 On some platforms OpenSSL is preinstalled as part of the Operating System.
192 In this case it is highly recommended not to overwrite the system versions,
193 because other applications or libraries might depend on it.
194 To avoid breaking other applications, install your copy of OpenSSL to a
195 [different location](#installing-to-a-different-location) which is not in
196 the global search path for system libraries.
198 Finally, if you plan on using the FIPS module, you need to read the
199 [Post-installation Notes](#post-installation-notes) further down.
201 ### Unix / Linux / macOS
203 Depending on your distribution, you need to run the following command as
204 root user or prepend `sudo` to the command:
208 By default, OpenSSL will be installed to
212 More precisely, the files will be installed into the subdirectories
219 depending on the file type, as it is custom on Unix-like operating systems.
223 Use the following command to install OpenSSL.
227 By default, OpenSSL will be installed to
233 If you are using Visual Studio, open the Developer Command Prompt _elevated_
234 and issue the following command.
238 The easiest way to elevate the Command Prompt is to press and hold down both
239 the `<CTRL>` and `<SHIFT>` keys while clicking the menu item in the task menu.
241 The default installation location is
243 C:\Program Files\OpenSSL
245 for native binaries, or
247 C:\Program Files (x86)\OpenSSL
249 for 32bit binaries on 64bit Windows (WOW64).
251 #### Installing to a different location
253 To install OpenSSL to a different location (for example into your home
254 directory for testing purposes) run `Configure` as shown in the following
257 The options `--prefix` and `--openssldir` are explained in further detail in
258 [Directories](#directories) below, and the values used here are mere examples.
262 $ ./Configure --prefix=/opt/openssl --openssldir=/usr/local/ssl
266 $ perl Configure --prefix=PROGRAM:[INSTALLS] --openssldir=SYS$MANAGER:[OPENSSL]
268 Note: if you do add options to the configuration command, please make sure
269 you've read more than just this Quick Start, such as relevant `NOTES-*` files,
270 the options outline below, as configuration options may change the outcome
271 in otherwise unexpected ways.
273 Configuration Options
274 =====================
276 There are several options to `./Configure` to customize the build (note that
277 for Windows, the defaults for `--prefix` and `--openssldir` depend on what
278 configuration is used and what Windows implementation OpenSSL is built on.
279 For more information, see the [Notes for Windows platforms](NOTES-WINDOWS.md).
286 Build the OpenSSL libraries to support the API for the specified version.
287 If [no-deprecated](#no-deprecated) is also given, don't build with support
288 for deprecated APIs in or below the specified version number. For example,
291 --api=1.1.0 no-deprecated
293 will remove support for all APIs that were deprecated in OpenSSL version
294 1.1.0 or below. This is a rather specialized option for developers.
295 If you just intend to remove all deprecated APIs up to the current version
296 entirely, just specify [no-deprecated](#no-deprecated).
297 If `--api` isn't given, it defaults to the current (minor) OpenSSL version.
302 --cross-compile-prefix=<PREFIX>
304 The `<PREFIX>` to include in front of commands for your toolchain.
306 It is likely to have to end with dash, e.g. `a-b-c-` would invoke GNU compiler
307 as `a-b-c-gcc`, etc. Unfortunately cross-compiling is too case-specific to put
308 together one-size-fits-all instructions. You might have to pass more flags or
309 set up environment variables to actually make it work. Android and iOS cases
310 are discussed in corresponding `Configurations/15-*.conf` files. But there are
311 cases when this option alone is sufficient. For example to build the mingw64
312 target on Linux `--cross-compile-prefix=x86_64-w64-mingw32-` works. Naturally
313 provided that mingw packages are installed. Today Debian and Ubuntu users
314 have option to install a number of prepackaged cross-compilers along with
315 corresponding run-time and development packages for "alien" hardware. To give
316 another example `--cross-compile-prefix=mipsel-linux-gnu-` suffices in such
319 For cross compilation, you must [configure manually](#manual-configuration).
320 Also, note that `--openssldir` refers to target's file system, not one you are
328 Build OpenSSL with debugging symbols and zero optimization level.
332 Build OpenSSL without debugging symbols. This is the default.
341 The name of the directory under the top of the installation directory tree
342 (see the `--prefix` option) where libraries will be installed. By default
343 this is `lib`. Note that on Windows only static libraries (`*.lib`) will
344 be stored in this location. Shared libraries (`*.dll`) will always be
345 installed to the `bin` directory.
347 Some build targets have a multilib postfix set in the build configuration.
348 For these targets the default libdir is `lib<multilib-postfix>`. Please use
349 `--libdir=lib` to override the libdir if adding the postfix is undesirable.
355 Directory for OpenSSL configuration files, and also the default certificate
356 and key store. Defaults are:
359 Windows: C:\Program Files\Common Files\SSL
360 OpenVMS: SYS$COMMON:[OPENSSL-COMMON]
362 For 32bit Windows applications on Windows 64bit (WOW64), always replace
363 `C:\Program Files` by `C:\Program Files (x86)`.
369 The top of the installation directory tree. Defaults are:
372 Windows: C:\Program Files\OpenSSL
373 OpenVMS: SYS$COMMON:[OPENSSL]
380 This is a developer flag that switches on various compiler options recommended
381 for OpenSSL development. It only works when using gcc or clang as the compiler.
382 If you are developing a patch for OpenSSL then it is recommended that you use
383 this option where possible.
385 Compression Algorithm Flags
386 ---------------------------
388 ### with-brotli-include
390 --with-brotli-include=DIR
392 The directory for the location of the brotli include files (i.e. the location
393 of the **brotli** include directory). This option is only necessary if
394 [enable-brotli](#enable-brotli) is used and the include files are not already
395 on the system include path.
399 --with-brotli-lib=LIB
401 **On Unix**: this is the directory containing the brotli libraries.
402 If not provided, the system library path will be used.
404 The names of the libraries are:
406 * libbrotlicommon.a or libbrotlicommon.so
407 * libbrotlidec.a or libbrotlidec.so
408 * libbrotlienc.a or libbrotlienc.so
410 **On Windows:** this is the directory containing the brotli libraries.
411 If not provided, the system library path will be used.
413 The names of the libraries are:
419 ### with-zlib-include
421 --with-zlib-include=DIR
423 The directory for the location of the zlib include file. This option is only
424 necessary if [zlib](#zlib) is used and the include file is not
425 already on the system include path.
431 **On Unix**: this is the directory containing the zlib library.
432 If not provided the system library path will be used.
434 **On Windows:** this is the filename of the zlib library (with or
435 without a path). This flag must be provided if the
436 [zlib-dynamic](#zlib-dynamic) option is not also used. If `zlib-dynamic` is used
437 then this flag is optional and defaults to `ZLIB1` if not provided.
439 **On VMS:** this is the filename of the zlib library (with or without a path).
440 This flag is optional and if not provided then `GNV$LIBZSHR`, `GNV$LIBZSHR32`
441 or `GNV$LIBZSHR64` is used by default depending on the pointer size chosen.
443 ### with-zstd-include
445 --with-zstd-include=DIR
447 The directory for the location of the Zstd include file. This option is only
448 necessary if [enable-std](#enable-zstd) is used and the include file is not
449 already on the system include path.
451 OpenSSL requires Zstd 1.4 or greater. The Linux kernel source contains a
452 *zstd.h* file that is not compatible with the 1.4.x Zstd distribution, the
453 compilation will generate an error if the Linux *zstd.h* is included before
454 (or instead of) the Zstd distribution header.
460 **On Unix**: this is the directory containing the Zstd library.
461 If not provided the system library path will be used.
463 **On Windows:** this is the filename of the Zstd library (with or
464 without a path). This flag must be provided if the
465 [enable-zstd-dynamic](#enable-zstd-dynamic) option is not also used.
466 If `zstd-dynamic` is used then this flag is optional and defaults
467 to `LIBZSTD` if not provided.
469 Seeding the Random Generator
470 ----------------------------
472 --with-rand-seed=seed1[,seed2,...]
474 A comma separated list of seeding methods which will be tried by OpenSSL
475 in order to obtain random input (a.k.a "entropy") for seeding its
476 cryptographically secure random number generator (CSPRNG).
477 The current seeding methods are:
481 Use a trusted operating system entropy source.
482 This is the default method if such an entropy source exists.
486 Use the [getrandom(2)][man-getrandom] or equivalent system call.
488 [man-getrandom]: http://man7.org/linux/man-pages/man2/getrandom.2.html
492 Use the first device from the `DEVRANDOM` list which can be opened to read
493 random bytes. The `DEVRANDOM` preprocessor constant expands to
495 "/dev/urandom","/dev/random","/dev/srandom"
497 on most unix-ish operating systems.
501 Check for an entropy generating daemon.
502 This source is ignored by the FIPS provider.
506 Use the `RDSEED` or `RDRAND` command on x86 or `RNDRRS` command on aarch64
507 if provided by the CPU.
511 Use librandom (not implemented yet).
512 This source is ignored by the FIPS provider.
516 Disable automatic seeding. This is the default on some operating systems where
517 no suitable entropy source exists, or no support for it is implemented yet.
518 This option is ignored by the FIPS provider.
520 For more information, see the section [Notes on random number generation][rng]
521 at the end of this document.
523 [rng]: #notes-on-random-number-generation
525 Setting the FIPS HMAC key
526 -------------------------
530 As part of its self-test validation, the FIPS module must verify itself
531 by performing a SHA-256 HMAC computation on itself. The default key is
532 the SHA256 value of "the holy handgrenade of antioch" and is sufficient
533 for meeting the FIPS requirements.
535 To change the key to a different value, use this flag. The value should
536 be a hex string no more than 64 characters.
538 Enable and Disable Features
539 ---------------------------
541 Feature options always come in pairs, an option to enable feature
542 `xxxx`, and an option to disable it:
544 [ enable-xxxx | no-xxxx ]
546 Whether a feature is enabled or disabled by default, depends on the feature.
547 In the following list, always the non-default variant is documented: if
548 feature `xxxx` is disabled by default then `enable-xxxx` is documented and
549 if feature `xxxx` is enabled by default then `no-xxxx` is documented.
553 Don't build the AFALG engine.
555 This option will be forced on a platform that does not support AFALG.
559 Build with Kernel TLS support.
561 This option will enable the use of the Kernel TLS data-path, which can improve
562 performance and allow for the use of sendfile and splice system calls on
563 TLS sockets. The Kernel may use TLS accelerators if any are available on the
564 system. This option will be forced off on systems that do not support the
565 Kernel TLS data-path.
569 Build with the Address sanitiser.
571 This is a developer option only. It may not work on all platforms and should
572 never be used in production environments. It will only work when used with
573 gcc or clang and should be used in conjunction with the [no-shared](#no-shared)
576 ### enable-acvp-tests
578 Build support for Automated Cryptographic Validation Protocol (ACVP)
581 This is required for FIPS validation purposes. Certain ACVP tests require
582 access to algorithm internals that are not normally accessible.
583 Additional information related to ACVP can be found at
584 <https://github.com/usnistgov/ACVP>.
588 Do not use assembler code.
590 This should be viewed as debugging/troubleshooting option rather than for
591 production use. On some platforms a small amount of assembler code may still
592 be used even with this option.
596 Do not build support for async operations.
600 Don't automatically load all supported ciphers and digests.
602 Typically OpenSSL will make available all of its supported ciphers and digests.
603 For a statically linked application this may be undesirable if small executable
604 size is an objective. This only affects libcrypto. Ciphers and digests will
605 have to be loaded manually using `EVP_add_cipher()` and `EVP_add_digest()`
606 if this option is used. This option will force a non-shared build.
610 Don't automatically load all libcrypto/libssl error strings.
612 Typically OpenSSL will automatically load human readable error strings. For a
613 statically linked application this may be undesirable if small executable size
618 Build with support for brotli compression/decompression.
620 ### enable-brotli-dynamic
622 Like the enable-brotli option, but has OpenSSL load the brotli library dynamically
625 This is only supported on systems where loading of shared libraries is supported.
627 ### no-autoload-config
629 Don't automatically load the default `openssl.cnf` file.
631 Typically OpenSSL will automatically load a system config file which configures
634 ### enable-buildtest-c++
636 While testing, generate C++ buildtest files that simply check that the public
637 OpenSSL header files are usable standalone with C++.
639 Enabling this option demands extra care. For any compiler flag given directly
640 as configuration option, you must ensure that it's valid for both the C and
641 the C++ compiler. If not, the C++ build test will most likely break. As an
642 alternative, you can use the language specific variables, `CFLAGS` and `CXXFLAGS`.
646 Use the specified text instead of the default banner at the end of
651 On platforms where the choice of 32-bit or 64-bit architecture
652 is not explicitly specified, `Configure` will print a warning
653 message and wait for a few seconds to let you interrupt the
654 configuration. Using this flag skips the wait.
658 Build only some minimal set of features.
659 This is a developer option used internally for CI build tests of the project.
663 Never cache algorithms when they are fetched from a provider. Normally, a
664 provider indicates if the algorithms it supplies can be cached or not. Using
665 this option will reduce run-time memory usage but it also introduces a
666 significant performance penalty. This option is primarily designed to help
667 with detecting incorrect reference counting.
671 Don't build the CAPI engine.
673 This option will be forced if on a platform that does not support CAPI.
677 Don't build support for Certificate Management Protocol (CMP)
678 and Certificate Request Message Format (CRMF).
682 Don't build support for Cryptographic Message Syntax (CMS).
686 Don't build support for SSL/TLS compression.
688 If this option is enabled (the default), then compression will only work if
689 the zlib or `zlib-dynamic` options are also chosen.
691 ### enable-crypto-mdebug
693 This now only enables the `failed-malloc` feature.
695 ### enable-crypto-mdebug-backtrace
697 This is a no-op; the project uses the compiler's address/leak sanitizer instead.
701 Don't build support for Certificate Transparency (CT).
705 Don't build with support for deprecated APIs up until and including the version
706 given with `--api` (or the current version, if `--api` wasn't specified).
710 Don't build support for datagram based BIOs.
712 Selecting this option will also force the disabling of DTLS.
716 Don't build support for loading Dynamic Shared Objects (DSO)
718 ### enable-devcryptoeng
720 Build the `/dev/crypto` engine.
722 This option is automatically selected on the BSD platform, in which case it can
723 be disabled with `no-devcryptoeng`.
725 ### no-dynamic-engine
727 Don't build the dynamically loaded engines.
729 This only has an effect in a shared build.
733 Don't build support for Elliptic Curves.
737 Don't build support for binary Elliptic Curves
739 ### enable-ec_nistp_64_gcc_128
741 Enable support for optimised implementations of some commonly used NIST
744 This option is only supported on platforms:
746 - with little-endian storage of non-byte types
747 - that tolerate misaligned memory references
748 - where the compiler:
749 - supports the non-standard type `__uint128_t`
750 - defines the built-in macro `__SIZEOF_INT128__`
754 Build support for gathering entropy from the Entropy Gathering Daemon (EGD).
758 Don't build support for loading engines.
762 Don't compile in any error strings.
764 ### enable-external-tests
766 Enable building of integration with external test suites.
768 This is a developer option and may not work on all platforms. The following
769 external test suites are currently supported:
771 - GOST engine test suite
772 - Python PYCA/Cryptography test suite
775 See the file [test/README-external.md](test/README-external.md)
780 Don't compile in filename and line number information (e.g. for errors and
785 Build (and install) the FIPS provider
787 ### no-fips-securitychecks
789 Don't perform FIPS module run-time checks related to enforcement of security
790 parameters such as minimum security strength of keys.
792 ### enable-fuzz-libfuzzer, enable-fuzz-afl
794 Build with support for fuzzing using either libfuzzer or AFL.
796 These are developer options only. They may not work on all platforms and
797 should never be used in production environments.
799 See the file [fuzz/README.md](fuzz/README.md) for further details.
803 Don't build support for GOST based ciphersuites.
805 Note that if this feature is enabled then GOST ciphersuites are only available
806 if the GOST algorithms are also available through loading an externally supplied
811 Don't build the legacy provider.
813 Disabling this also disables the legacy algorithms: MD2 (already disabled by default).
817 Don't generate dependencies.
821 Don't build any dynamically loadable engines.
823 This also implies `no-dynamic-engine`.
827 Don't build support for writing multiple records in one go in libssl
829 Note: this is a different capability to the pipelining functionality.
833 Don't build support for the Next Protocol Negotiation (NPN) TLS extension.
837 Don't build support for Online Certificate Status Protocol (OCSP).
841 Don't build the padlock engine.
845 As synonym for `no-padlockeng`. Deprecated and should not be used.
849 Don't build with support for Position Independent Code.
853 Don't pin the shared libraries.
855 By default OpenSSL will attempt to stay in memory until the process exits.
856 This is so that libcrypto and libssl can be properly cleaned up automatically
857 via an `atexit()` handler. The handler is registered by libcrypto and cleans
858 up both libraries. On some platforms the `atexit()` handler will run on unload of
859 libcrypto (if it has been dynamically loaded) rather than at process exit.
861 This option can be used to stop OpenSSL from attempting to stay in memory until the
862 process exits. This could lead to crashes if either libcrypto or libssl have
863 already been unloaded at the point that the atexit handler is invoked, e.g. on a
864 platform which calls `atexit()` on unload of the library, and libssl is unloaded
865 before libcrypto then a crash is likely to happen.
867 Note that shared library pinning is not automatically disabled for static builds,
868 i.e., `no-shared` does not imply `no-pinshared`. This may come as a surprise when
869 linking libcrypto statically into a shared third-party library, because in this
870 case the shared library will be pinned. To prevent this behaviour, you need to
871 configure the static build using `no-shared` and `no-pinshared` together.
873 Applications can suppress running of the `atexit()` handler at run time by
874 using the `OPENSSL_INIT_NO_ATEXIT` option to `OPENSSL_init_crypto()`.
875 See the man page for it for further details.
879 Don't use POSIX IO capabilities.
883 Don't build support for Pre-Shared Key based ciphersuites.
887 Don't use hardware RDRAND capabilities.
891 Don't build support for RFC3779, "X.509 Extensions for IP Addresses and
896 Build support for Stream Control Transmission Protocol (SCTP).
900 Do not create shared libraries, only static ones.
902 See [Notes on shared libraries](#notes-on-shared-libraries) below.
906 Don't build support for socket BIOs.
910 Don't build support for Secure Remote Password (SRP) protocol or
911 SRP based ciphersuites.
915 Don't build Secure Real-Time Transport Protocol (SRTP) support.
919 Exclude SSE2 code paths from 32-bit x86 assembly modules.
921 Normally SSE2 extension is detected at run-time, but the decision whether or not
922 the machine code will be executed is taken solely on CPU capability vector. This
923 means that if you happen to run OS kernel which does not support SSE2 extension
924 on Intel P4 processor, then your application might be exposed to "illegal
925 instruction" exception. There might be a way to enable support in kernel, e.g.
926 FreeBSD kernel can be compiled with `CPU_ENABLE_SSE`, and there is a way to
927 disengage SSE2 code paths upon application start-up, but if you aim for wider
928 "audience" running such kernel, consider `no-sse2`. Both the `386` and `no-asm`
929 options imply `no-sse2`.
933 Don't build with SSL Trace capabilities.
935 This removes the `-trace` option from `s_client` and `s_server`, and omits the
936 `SSL_trace()` function from libssl.
938 Disabling `ssl-trace` may provide a small reduction in libssl binary size.
942 Don't build the statically linked engines.
944 This only has an impact when not built "shared".
948 Don't use anything from the C header file `stdio.h` that makes use of the `FILE`
949 type. Only libcrypto and libssl can be built in this way. Using this option will
950 suppress building the command line applications. Additionally, since the OpenSSL
951 tests also use the command line applications, the tests will also be skipped.
955 Don't build test programs or run any tests.
959 Build with support for TCP Fast Open (RFC7413). Supported on Linux, macOS and FreeBSD.
963 Build with QUIC support. This is currently just for developers as the
964 implementation is by no means complete and usable.
968 Don't build with support for multi-threaded applications.
972 Build with support for multi-threaded applications. Most platforms will enable
973 this by default. However, if on a platform where this is not the case then this
974 will usually require additional system-dependent options!
976 See [Notes on multi-threading](#notes-on-multi-threading) below.
980 Don't build with support for thread pool functionality.
984 Build with thread pool functionality. If enabled, OpenSSL algorithms may
985 use the thread pool to perform parallel computation. This option in itself
986 does not enable OpenSSL to spawn new threads. Currently the only supported
987 thread pool mechanism is the default thread pool.
989 ### no-default-thread-pool
991 Don't build with support for default thread pool functionality.
993 ### default-thread-pool
995 Build with default thread pool functionality. If enabled, OpenSSL may create
996 and manage threads up to a maximum number of threads authorized by the
997 application. Supported on POSIX compliant platforms and Windows.
1001 Build with support for the integrated tracing api.
1003 See manual pages OSSL_trace_set_channel(3) and OSSL_trace_enabled(3) for details.
1007 Don't build Time Stamping (TS) Authority support.
1011 Build with the Undefined Behaviour sanitiser (UBSAN).
1013 This is a developer option only. It may not work on all platforms and should
1014 never be used in production environments. It will only work when used with
1015 gcc or clang and should be used in conjunction with the `-DPEDANTIC` option
1016 (or the `--strict-warnings` option).
1020 Don't build with the User Interface (UI) console method
1022 The User Interface console method enables text based console prompts.
1024 ### enable-unit-test
1026 Enable additional unit test APIs.
1028 This should not typically be used in production deployments.
1032 Don't build support for UPLINK interface.
1034 ### enable-weak-ssl-ciphers
1036 Build support for SSL/TLS ciphers that are considered "weak"
1038 Enabling this includes for example the RC4 based ciphersuites.
1042 Build with support for zlib compression/decompression.
1046 Like the zlib option, but has OpenSSL load the zlib library dynamically
1049 This is only supported on systems where loading of shared libraries is supported.
1053 Build with support for Zstd compression/decompression.
1055 ### enable-zstd-dynamic
1057 Like the enable-zstd option, but has OpenSSL load the Zstd library dynamically
1060 This is only supported on systems where loading of shared libraries is supported.
1064 In 32-bit x86 builds, use the 80386 instruction set only in assembly modules
1066 The default x86 code is more efficient, but requires at least an 486 processor.
1067 Note: This doesn't affect compiler generated code, so this option needs to be
1068 accompanied by a corresponding compiler-specific option.
1072 no-{ssl|ssl3|tls|tls1|tls1_1|tls1_2|tls1_3|dtls|dtls1|dtls1_2}
1074 Don't build support for negotiating the specified SSL/TLS protocol.
1076 If `no-tls` is selected then all of `tls1`, `tls1_1`, `tls1_2` and `tls1_3`
1078 Similarly `no-dtls` will disable `dtls1` and `dtls1_2`. The `no-ssl` option is
1079 synonymous with `no-ssl3`. Note this only affects version negotiation.
1080 OpenSSL will still provide the methods for applications to explicitly select
1081 the individual protocol versions.
1083 ### no-{protocol}-method
1085 no-{ssl3|tls1|tls1_1|tls1_2|dtls1|dtls1_2}-method
1087 Analogous to `no-{protocol}` but in addition do not build the methods for
1088 applications to explicitly select individual protocol versions. Note that there
1089 is no `no-tls1_3-method` option because there is no application method for
1092 Using individual protocol methods directly is deprecated. Applications should
1093 use `TLS_method()` instead.
1095 ### enable-{algorithm}
1099 Build with support for the specified algorithm.
1103 no-{aria|bf|blake2|camellia|cast|chacha|cmac|
1104 des|dh|dsa|ecdh|ecdsa|idea|md4|mdc2|ocb|
1105 poly1305|rc2|rc4|rmd160|scrypt|seed|
1106 siphash|siv|sm2|sm3|sm4|whirlpool}
1108 Build without support for the specified algorithm.
1110 The `ripemd` algorithm is deprecated and if used is synonymous with `rmd160`.
1112 ### Compiler-specific options
1114 -Dxxx, -Ixxx, -Wp, -lxxx, -Lxxx, -Wl, -rpath, -R, -framework, -static
1116 These system specific options will be recognised and passed through to the
1117 compiler to allow you to define preprocessor symbols, specify additional
1118 libraries, library directories or other compiler options. It might be worth
1119 noting that some compilers generate code specifically for processor the
1120 compiler currently executes on. This is not necessarily what you might have
1121 in mind, since it might be unsuitable for execution on other, typically older,
1122 processor. Consult your compiler documentation.
1124 Take note of the [Environment Variables](#environment-variables) documentation
1125 below and how these flags interact with those variables.
1129 Additional options that are not otherwise recognised are passed through as
1130 they are to the compiler as well. Unix-style options beginning with a
1131 `-` or `+` and Windows-style options beginning with a `/` are recognised.
1132 Again, consult your compiler documentation.
1134 If the option contains arguments separated by spaces, then the URL-style
1135 notation `%20` can be used for the space character in order to avoid having
1136 to quote the option. For example, `-opt%20arg` gets expanded to `-opt arg`.
1137 In fact, any ASCII character can be encoded as %xx using its hexadecimal
1140 Take note of the [Environment Variables](#environment-variables) documentation
1141 below and how these flags interact with those variables.
1143 ### Environment Variables
1147 Assign the given value to the environment variable `VAR` for `Configure`.
1149 These work just like normal environment variable assignments, but are supported
1150 on all platforms and are confined to the configuration scripts only.
1151 These assignments override the corresponding value in the inherited environment,
1154 The following variables are used as "`make` variables" and can be used as an
1155 alternative to giving preprocessor, compiler and linker options directly as
1156 configuration. The following variables are supported:
1158 AR The static library archiver.
1159 ARFLAGS Flags for the static library archiver.
1160 AS The assembler compiler.
1161 ASFLAGS Flags for the assembler compiler.
1163 CFLAGS Flags for the C compiler.
1164 CXX The C++ compiler.
1165 CXXFLAGS Flags for the C++ compiler.
1166 CPP The C/C++ preprocessor.
1167 CPPFLAGS Flags for the C/C++ preprocessor.
1168 CPPDEFINES List of CPP macro definitions, separated
1169 by a platform specific character (':' or
1170 space for Unix, ';' for Windows, ',' for
1171 VMS). This can be used instead of using
1172 -D (or what corresponds to that on your
1173 compiler) in CPPFLAGS.
1174 CPPINCLUDES List of CPP inclusion directories, separated
1175 the same way as for CPPDEFINES. This can
1176 be used instead of -I (or what corresponds
1177 to that on your compiler) in CPPFLAGS.
1178 HASHBANGPERL Perl invocation to be inserted after '#!'
1179 in public perl scripts (only relevant on
1181 LD The program linker (not used on Unix, $(CC)
1183 LDFLAGS Flags for the shared library, DSO and
1185 LDLIBS Extra libraries to use when linking.
1186 Takes the form of a space separated list
1187 of library specifications on Unix and
1188 Windows, and as a comma separated list of
1190 RANLIB The library archive indexer.
1191 RC The Windows resource compiler.
1192 RCFLAGS Flags for the Windows resource compiler.
1193 RM The command to remove files and directories.
1195 These cannot be mixed with compiling/linking flags given on the command line.
1196 In other words, something like this isn't permitted.
1198 $ ./Configure -DFOO CPPFLAGS=-DBAR -DCOOKIE
1200 Backward compatibility note:
1202 To be compatible with older configuration scripts, the environment variables
1203 are ignored if compiling/linking flags are given on the command line, except
1206 AR, CC, CXX, CROSS_COMPILE, HASHBANGPERL, PERL, RANLIB, RC, and WINDRES
1208 For example, the following command will not see `-DBAR`:
1210 $ CPPFLAGS=-DBAR ./Configure -DCOOKIE
1212 However, the following will see both set variables:
1214 $ CC=gcc CROSS_COMPILE=x86_64-w64-mingw32- ./Configure -DCOOKIE
1216 If `CC` is set, it is advisable to also set `CXX` to ensure both the C and C++
1217 compiler are in the same "family". This becomes relevant with
1218 `enable-external-tests` and `enable-buildtest-c++`.
1225 Reconfigure from earlier data.
1227 This fetches the previous command line options and environment from data
1228 saved in `configdata.pm` and runs the configuration process again, using
1229 these options and environment. Note: NO other option is permitted together
1230 with `reconf`. Note: The original configuration saves away values for ALL
1231 environment variables that were used, and if they weren't defined, they are
1232 still saved away with information that they weren't originally defined.
1233 This information takes precedence over environment variables that are
1234 defined when reconfiguring.
1236 Displaying configuration data
1237 -----------------------------
1239 The configuration script itself will say very little, and finishes by
1240 creating `configdata.pm`. This perl module can be loaded by other scripts
1241 to find all the configuration data, and it can also be used as a script to
1242 display all sorts of configuration data in a human readable form.
1244 For more information, please do:
1246 $ ./configdata.pm --help # Unix
1250 $ perl configdata.pm --help # Windows and VMS
1252 Installation Steps in Detail
1253 ============================
1258 ### Automatic Configuration
1260 In previous version, the `config` script determined the platform type and
1261 compiler and then called `Configure`. Starting with this release, they are
1264 #### Unix / Linux / macOS
1266 $ ./Configure [options...]
1270 $ perl Configure [options...]
1274 $ perl Configure [options...]
1276 ### Manual Configuration
1278 OpenSSL knows about a range of different operating system, hardware and
1279 compiler combinations. To see the ones it knows about, run
1281 $ ./Configure LIST # Unix
1285 $ perl Configure LIST # All other platforms
1287 For the remainder of this text, the Unix form will be used in all examples.
1288 Please use the appropriate form for your platform.
1290 Pick a suitable name from the list that matches your system. For most
1291 operating systems there is a choice between using cc or gcc.
1292 When you have identified your system (and if necessary compiler) use this
1293 name as the argument to `Configure`. For example, a `linux-elf` user would
1296 $ ./Configure linux-elf [options...]
1298 ### Creating your own Configuration
1300 If your system isn't listed, you will have to create a configuration
1301 file named `Configurations/YOURFILENAME.conf` (replace `YOURFILENAME`
1302 with a filename of your choosing) and add the correct
1303 configuration for your system. See the available configs as examples
1304 and read [Configurations/README.md](Configurations/README.md) and
1305 [Configurations/README-design.md](Configurations/README-design.md)
1306 for more information.
1308 The generic configurations `cc` or `gcc` should usually work on 32 bit
1311 `Configure` creates a build file (`Makefile` on Unix, `makefile` on Windows
1312 and `descrip.mms` on OpenVMS) from a suitable template in `Configurations/`,
1313 and defines various macros in `include/openssl/configuration.h` (generated
1314 from `include/openssl/configuration.h.in`.
1316 If none of the generated build files suit your purpose, it's possible to
1317 write your own build file template and give its name through the environment
1318 variable `BUILDFILE`. For example, Ninja build files could be supported by
1319 writing `Configurations/build.ninja.tmpl` and then configure with `BUILDFILE`
1320 set like this (Unix syntax shown, you'll have to adapt for other platforms):
1322 $ BUILDFILE=build.ninja perl Configure [options...]
1324 ### Out of Tree Builds
1326 OpenSSL can be configured to build in a build directory separate from the
1327 source code directory. It's done by placing yourself in some other
1328 directory and invoking the configuration commands from there.
1332 $ mkdir /var/tmp/openssl-build
1333 $ cd /var/tmp/openssl-build
1334 $ /PATH/TO/OPENSSL/SOURCE/Configure [options...]
1336 #### OpenVMS example
1338 $ set default sys$login:
1339 $ create/dir [.tmp.openssl-build]
1340 $ set default [.tmp.openssl-build]
1341 $ perl D:[PATH.TO.OPENSSL.SOURCE]Configure [options...]
1343 #### Windows example
1346 $ mkdir \temp-openssl
1348 $ perl d:\PATH\TO\OPENSSL\SOURCE\Configure [options...]
1350 Paths can be relative just as well as absolute. `Configure` will do its best
1351 to translate them to relative paths whenever possible.
1356 Build OpenSSL by running:
1359 $ mms ! (or mmk) OpenVMS
1362 This will build the OpenSSL libraries (`libcrypto.a` and `libssl.a` on
1363 Unix, corresponding on other platforms) and the OpenSSL binary
1364 (`openssl`). The libraries will be built in the top-level directory,
1365 and the binary will be in the `apps/` subdirectory.
1367 If the build fails, take a look at the [Build Failures](#build-failures)
1368 subsection of the [Troubleshooting](#troubleshooting) section.
1373 After a successful build, and before installing, the libraries should
1377 $ mms test ! OpenVMS
1378 $ nmake test # Windows
1380 **Warning:** you MUST run the tests from an unprivileged account (or disable
1381 your privileges temporarily if your platform allows it).
1383 See [test/README.md](test/README.md) for further details how run tests.
1385 See [test/README-dev.md](test/README-dev.md) for guidelines on adding tests.
1390 If everything tests ok, install OpenSSL with
1392 $ make install # Unix
1393 $ mms install ! OpenVMS
1394 $ nmake install # Windows
1396 Note that in order to perform the install step above you need to have
1397 appropriate permissions to write to the installation directory.
1399 The above commands will install all the software components in this
1400 directory tree under `<PREFIX>` (the directory given with `--prefix` or
1403 ### Unix / Linux / macOS
1405 bin/ Contains the openssl binary and a few other
1408 Contains the header files needed if you want
1409 to build your own programs that use libcrypto
1411 lib Contains the OpenSSL library files.
1412 lib/engines Contains the OpenSSL dynamically loadable engines.
1414 share/man/man1 Contains the OpenSSL command line man-pages.
1415 share/man/man3 Contains the OpenSSL library calls man-pages.
1416 share/man/man5 Contains the OpenSSL configuration format man-pages.
1417 share/man/man7 Contains the OpenSSL other misc man-pages.
1419 share/doc/openssl/html/man1
1420 share/doc/openssl/html/man3
1421 share/doc/openssl/html/man5
1422 share/doc/openssl/html/man7
1423 Contains the HTML rendition of the man-pages.
1427 'arch' is replaced with the architecture name, `ALPHA` or `IA64`,
1428 'sover' is replaced with the shared library version (`0101` for 1.1), and
1429 'pz' is replaced with the pointer size OpenSSL was built with:
1431 [.EXE.'arch'] Contains the openssl binary.
1432 [.EXE] Contains a few utility scripts.
1434 Contains the header files needed if you want
1435 to build your own programs that use libcrypto
1437 [.LIB.'arch'] Contains the OpenSSL library files.
1438 [.ENGINES'sover''pz'.'arch']
1439 Contains the OpenSSL dynamically loadable engines.
1440 [.SYS$STARTUP] Contains startup, login and shutdown scripts.
1441 These define appropriate logical names and
1443 [.SYSTEST] Contains the installation verification procedure.
1444 [.HTML] Contains the HTML rendition of the manual pages.
1446 ### Additional Directories
1448 Additionally, install will add the following directories under
1449 OPENSSLDIR (the directory given with `--openssldir` or its default)
1450 for you convenience:
1452 certs Initially empty, this is the default location
1453 for certificate files.
1454 private Initially empty, this is the default location
1455 for private key files.
1456 misc Various scripts.
1458 The installation directory should be appropriately protected to ensure
1459 unprivileged users cannot make changes to OpenSSL binaries or files, or
1460 install engines. If you already have a pre-installed version of OpenSSL as
1461 part of your Operating System it is recommended that you do not overwrite
1462 the system version and instead install to somewhere else.
1464 Package builders who want to configure the library for standard locations,
1465 but have the package installed somewhere else so that it can easily be
1468 $ make DESTDIR=/tmp/package-root install # Unix
1469 $ mms/macro="DESTDIR=TMP:[PACKAGE-ROOT]" install ! OpenVMS
1471 The specified destination directory will be prepended to all installation
1474 Compatibility issues with previous OpenSSL versions
1475 ---------------------------------------------------
1477 ### COMPILING existing applications
1479 Starting with version 1.1.0, OpenSSL hides a number of structures that were
1480 previously open. This includes all internal libssl structures and a number
1481 of EVP types. Accessor functions have been added to allow controlled access
1482 to the structures' data.
1484 This means that some software needs to be rewritten to adapt to the new ways
1485 of doing things. This often amounts to allocating an instance of a structure
1486 explicitly where you could previously allocate them on the stack as automatic
1487 variables, and using the provided accessor functions where you would previously
1488 access a structure's field directly.
1490 Some APIs have changed as well. However, older APIs have been preserved when
1493 Post-installation Notes
1494 -----------------------
1496 With the default OpenSSL installation comes a FIPS provider module, which
1497 needs some post-installation attention, without which it will not be usable.
1498 This involves using the following command:
1500 $ openssl fipsinstall
1502 See the openssl-fipsinstall(1) manual for details and examples.
1504 Advanced Build Options
1505 ======================
1507 Environment Variables
1508 ---------------------
1510 A number of environment variables can be used to provide additional control
1511 over the build process. Typically these should be defined prior to running
1512 `Configure`. Not all environment variables are relevant to all platforms.
1515 The name of the ar executable to use.
1518 Use a different build file name than the platform default
1519 ("Makefile" on Unix-like platforms, "makefile" on native Windows,
1520 "descrip.mms" on OpenVMS). This requires that there is a
1521 corresponding build file template.
1522 See [Configurations/README.md](Configurations/README.md)
1523 for further information.
1526 The compiler to use. Configure will attempt to pick a default
1527 compiler for your platform but this choice can be overridden
1528 using this variable. Set it to the compiler executable you wish
1529 to use, e.g. gcc or clang.
1532 This environment variable has the same meaning as for the
1533 "--cross-compile-prefix" Configure flag described above. If both
1534 are set then the Configure flag takes precedence.
1537 The command string for the Perl executable to insert in the
1538 #! line of perl scripts that will be publicly installed.
1539 Default: /usr/bin/env perl
1540 Note: the value of this variable is added to the same scripts
1541 on all platforms, but it's only relevant on Unix-like platforms.
1544 This can be the value `32` or `64` to specify the architecture
1545 when it is not "obvious" to the configuration. It should generally
1546 not be necessary to specify this environment variable.
1549 The name of the nm executable to use.
1551 OPENSSL_LOCAL_CONFIG_DIR
1552 OpenSSL comes with a database of information about how it
1553 should be built on different platforms as well as build file
1554 templates for those platforms. The database is comprised of
1555 ".conf" files in the Configurations directory. The build
1556 file templates reside there as well as ".tmpl" files. See the
1557 file [Configurations/README.md](Configurations/README.md)
1558 for further information about the format of ".conf" files
1559 as well as information on the ".tmpl" files.
1560 In addition to the standard ".conf" and ".tmpl" files, it is
1561 possible to create your own ".conf" and ".tmpl" files and
1562 store them locally, outside the OpenSSL source tree.
1563 This environment variable can be set to the directory where
1564 these files are held and will be considered by Configure
1565 before it looks in the standard directories.
1568 The name of the Perl executable to use when building OpenSSL.
1569 Only needed if building should use a different Perl executable
1570 than what is used to run the Configure script.
1573 The name of the ranlib executable to use.
1576 The name of the rc executable to use. The default will be as
1577 defined for the target platform in the ".conf" file. If not
1578 defined then "windres" will be used. The WINDRES environment
1579 variable is synonymous to this. If both are defined then RC
1588 The `Configure` script generates a Makefile in a format relevant to the specific
1589 platform. The Makefiles provide a number of targets that can be used. Not all
1590 targets may be available on all platforms. Only the most common targets are
1591 described here. Examine the Makefiles themselves for the full list.
1594 The target to build all the software components and
1598 Build all the software components.
1599 THIS IS THE DEFAULT TARGET.
1602 Build all documentation components.
1605 Remove all build artefacts and return the directory to a "clean"
1609 Rebuild the dependencies in the Makefiles. This is a legacy
1610 option that no longer needs to be used since OpenSSL 1.1.0.
1613 Install all OpenSSL components.
1616 Only install the OpenSSL software components.
1619 Only install the OpenSSL documentation components.
1622 Only install the OpenSSL man pages (Unix only).
1625 Only install the OpenSSL HTML documentation.
1628 Install the FIPS provider module configuration file.
1631 Prints a list of all the self test names.
1634 Build and run the OpenSSL self tests.
1637 Uninstall all OpenSSL components.
1641 Re-run the configuration process, as exactly as the last time
1645 This is a developer option. If you are developing a patch for
1646 OpenSSL you may need to use this if you want to update
1647 automatically generated files; add new error codes or add new
1648 (or change the visibility of) public API functions. (Unix only).
1650 Running Selected Tests
1651 ----------------------
1653 You can specify a set of tests to be performed
1654 using the `make` variable `TESTS`.
1656 See the section [Running Selected Tests of
1657 test/README.md](test/README.md#running-selected-tests).
1662 Configuration Problems
1663 ----------------------
1665 ### Selecting the correct target
1667 The `./Configure` script tries hard to guess your operating system, but in some
1668 cases it does not succeed. You will see a message like the following:
1671 Operating system: x86-whatever-minix
1672 This system (minix) is not supported. See file INSTALL.md for details.
1674 Even if the automatic target selection by the `./Configure` script fails,
1675 chances are that you still might find a suitable target in the `Configurations`
1676 directory, which you can supply to the `./Configure` command,
1677 possibly after some adjustment.
1679 The `Configurations/` directory contains a lot of examples of such targets.
1680 The main configuration file is [10-main.conf], which contains all targets that
1681 are officially supported by the OpenSSL team. Other configuration files contain
1682 targets contributed by other OpenSSL users. The list of targets can be found in
1683 a Perl list `my %targets = ( ... )`.
1688 inherit_from => [ "base-target" ],
1690 cflags => add("..."),
1692 perlasm_scheme => "...",
1697 If you call `./Configure` without arguments, it will give you a list of all
1698 known targets. Using `grep`, you can lookup the target definition in the
1699 `Configurations/` directory. For example the `android-x86_64` can be found in
1700 [Configurations/15-android.conf](Configurations/15-android.conf).
1702 The directory contains two README files, which explain the general syntax and
1703 design of the configuration files.
1705 - [Configurations/README.md](Configurations/README.md)
1706 - [Configurations/README-design.md](Configurations/README-design.md)
1708 If you need further help, try to search the [openssl-users] mailing list
1709 or the [GitHub Issues] for existing solutions. If you don't find anything,
1710 you can [raise an issue] to ask a question yourself.
1712 More about our support resources can be found in the [SUPPORT] file.
1714 ### Configuration Errors
1716 If the `./Configure` or `./Configure` command fails with an error message,
1717 read the error message carefully and try to figure out whether you made
1718 a mistake (e.g., by providing a wrong option), or whether the script is
1719 working incorrectly. If you think you encountered a bug, please
1720 [raise an issue] on GitHub to file a bug report.
1722 Along with a short description of the bug, please provide the complete
1723 configure command line and the relevant output including the error message.
1725 Note: To make the output readable, please add a 'code fence' (three backquotes
1726 ` ``` ` on a separate line) before and after your output:
1729 ./Configure [your arguments...]
1738 If the build fails, look carefully at the output. Try to locate and understand
1739 the error message. It might be that the compiler is already telling you
1740 exactly what you need to do to fix your problem.
1742 There may be reasons for the failure that aren't problems in OpenSSL itself,
1743 for example if the compiler reports missing standard or third party headers.
1745 If the build succeeded previously, but fails after a source or configuration
1746 change, it might be helpful to clean the build tree before attempting another
1747 build. Use this command:
1750 $ mms clean ! (or mmk) OpenVMS
1751 $ nmake clean # Windows
1753 Assembler error messages can sometimes be sidestepped by using the `no-asm`
1754 configuration option. See also [notes](#notes-on-assembler-modules-compilation).
1756 Compiling parts of OpenSSL with gcc and others with the system compiler will
1757 result in unresolved symbols on some systems.
1759 If you are still having problems, try to search the [openssl-users] mailing
1760 list or the [GitHub Issues] for existing solutions. If you think you
1761 encountered an OpenSSL bug, please [raise an issue] to file a bug report.
1762 Please take the time to review the existing issues first; maybe the bug was
1763 already reported or has already been fixed.
1768 If some tests fail, look at the output. There may be reasons for the failure
1769 that isn't a problem in OpenSSL itself (like an OS malfunction or a Perl issue).
1771 You may want increased verbosity, that can be accomplished as described in
1772 section [Test Failures of test/README.md](test/README.md#test-failures).
1774 You may also want to selectively specify which test(s) to perform. This can be
1775 done using the `make` variable `TESTS` as described in section [Running
1776 Selected Tests of test/README.md](test/README.md#running-selected-tests).
1778 If you find a problem with OpenSSL itself, try removing any
1779 compiler optimization flags from the `CFLAGS` line in the Makefile and
1780 run `make clean; make` or corresponding.
1782 To report a bug please open an issue on GitHub, at
1783 <https://github.com/openssl/openssl/issues>.
1788 Notes on multi-threading
1789 ------------------------
1791 For some systems, the OpenSSL `Configure` script knows what compiler options
1792 are needed to generate a library that is suitable for multi-threaded
1793 applications. On these systems, support for multi-threading is enabled
1794 by default; use the `no-threads` option to disable (this should never be
1797 On other systems, to enable support for multi-threading, you will have
1798 to specify at least two options: `threads`, and a system-dependent option.
1799 (The latter is `-D_REENTRANT` on various systems.) The default in this
1800 case, obviously, is not to include support for multi-threading (but
1801 you can still use `no-threads` to suppress an annoying warning message
1802 from the `Configure` script.)
1804 OpenSSL provides built-in support for two threading models: pthreads (found on
1805 most UNIX/Linux systems), and Windows threads. No other threading models are
1806 supported. If your platform does not provide pthreads or Windows threads then
1807 you should use `Configure` with the `no-threads` option.
1809 For pthreads, all locks are non-recursive. In addition, in a debug build,
1810 the mutex attribute `PTHREAD_MUTEX_ERRORCHECK` is used. If this is not
1811 available on your platform, you might have to add
1812 `-DOPENSSL_NO_MUTEX_ERRORCHECK` to your `Configure` invocation.
1813 (On Linux `PTHREAD_MUTEX_ERRORCHECK` is an enum value, so a built-in
1814 ifdef test cannot be used.)
1816 Notes on shared libraries
1817 -------------------------
1819 For most systems the OpenSSL `Configure` script knows what is needed to
1820 build shared libraries for libcrypto and libssl. On these systems
1821 the shared libraries will be created by default. This can be suppressed and
1822 only static libraries created by using the `no-shared` option. On systems
1823 where OpenSSL does not know how to build shared libraries the `no-shared`
1824 option will be forced and only static libraries will be created.
1826 Shared libraries are named a little differently on different platforms.
1827 One way or another, they all have the major OpenSSL version number as
1828 part of the file name, i.e. for OpenSSL 1.1.x, `1.1` is somehow part of
1831 On most POSIX platforms, shared libraries are named `libcrypto.so.1.1`
1832 and `libssl.so.1.1`.
1834 on Cygwin, shared libraries are named `cygcrypto-1.1.dll` and `cygssl-1.1.dll`
1835 with import libraries `libcrypto.dll.a` and `libssl.dll.a`.
1837 On Windows build with MSVC or using MingW, shared libraries are named
1838 `libcrypto-1_1.dll` and `libssl-1_1.dll` for 32-bit Windows,
1839 `libcrypto-1_1-x64.dll` and `libssl-1_1-x64.dll` for 64-bit x86_64 Windows,
1840 and `libcrypto-1_1-ia64.dll` and `libssl-1_1-ia64.dll` for IA64 Windows.
1841 With MSVC, the import libraries are named `libcrypto.lib` and `libssl.lib`,
1842 while with MingW, they are named `libcrypto.dll.a` and `libssl.dll.a`.
1844 On VMS, shareable images (VMS speak for shared libraries) are named
1845 `ossl$libcrypto0101_shr.exe` and `ossl$libssl0101_shr.exe`. However, when
1846 OpenSSL is specifically built for 32-bit pointers, the shareable images
1847 are named `ossl$libcrypto0101_shr32.exe` and `ossl$libssl0101_shr32.exe`
1848 instead, and when built for 64-bit pointers, they are named
1849 `ossl$libcrypto0101_shr64.exe` and `ossl$libssl0101_shr64.exe`.
1851 Notes on random number generation
1852 ---------------------------------
1854 Availability of cryptographically secure random numbers is required for
1855 secret key generation. OpenSSL provides several options to seed the
1856 internal CSPRNG. If not properly seeded, the internal CSPRNG will refuse
1857 to deliver random bytes and a "PRNG not seeded error" will occur.
1859 The seeding method can be configured using the `--with-rand-seed` option,
1860 which can be used to specify a comma separated list of seed methods.
1861 However, in most cases OpenSSL will choose a suitable default method,
1862 so it is not necessary to explicitly provide this option. Note also
1863 that not all methods are available on all platforms. The FIPS provider will
1864 silently ignore seed sources that were not validated.
1866 I) On operating systems which provide a suitable randomness source (in
1867 form of a system call or system device), OpenSSL will use the optimal
1868 available method to seed the CSPRNG from the operating system's
1869 randomness sources. This corresponds to the option `--with-rand-seed=os`.
1871 II) On systems without such a suitable randomness source, automatic seeding
1872 and reseeding is disabled (`--with-rand-seed=none`) and it may be necessary
1873 to install additional support software to obtain a random seed and reseed
1874 the CSPRNG manually. Please check out the manual pages for `RAND_add()`,
1875 `RAND_bytes()`, `RAND_egd()`, and the FAQ for more information.
1877 Notes on assembler modules compilation
1878 --------------------------------------
1880 Compilation of some code paths in assembler modules might depend on whether the
1881 current assembler version supports certain ISA extensions or not. Code paths
1882 that use the AES-NI, PCLMULQDQ, SSSE3, and SHA extensions are always assembled.
1883 Apart from that, the minimum requirements for the assembler versions are shown
1886 | ISA extension | GNU as | nasm | llvm |
1887 |---------------|--------|--------|---------|
1888 | AVX | 2.19 | 2.09 | 3.0 |
1889 | AVX2 | 2.22 | 2.10 | 3.1 |
1890 | ADCX/ADOX | 2.23 | 2.10 | 3.3 |
1891 | AVX512 | 2.25 | 2.11.8 | 3.6 (*) |
1892 | AVX512IFMA | 2.26 | 2.11.8 | 6.0 (*) |
1893 | VAES | 2.30 | 2.13.3 | 6.0 (*) |
1897 (*) Even though AVX512 support was implemented in llvm 3.6, prior to version 7.0
1898 an explicit -march flag was apparently required to compile assembly modules. But
1899 then the compiler generates processor-specific code, which in turn contradicts
1900 the idea of performing dispatch at run-time, which is facilitated by the special
1901 variable `OPENSSL_ia32cap`. For versions older than 7.0, it is possible to work
1902 around the problem by forcing the build procedure to use the following script:
1905 exec clang -no-integrated-as "$@"
1907 instead of the real clang. In which case it doesn't matter what clang version
1908 is used, as it is the version of the GNU assembler that will be checked.
1915 <https://mta.openssl.org/mailman/listinfo/openssl-users>
1921 <https://github.com/openssl/openssl/issues>
1924 <https://github.com/openssl/openssl/issues/new/choose>
1927 Configurations/10-main.conf