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` target for 64bit Windows
171 binaries (AMD64) or `VC-WIN32` for 32bit Windows binaries (X86).
172 The other two options are `VC-WIN64I` (Intel IA64, Itanium) and
173 `VC-CE` (Windows CE) are rather uncommon nowadays.
178 The following commands will install OpenSSL to a default system location.
180 **Danger Zone:** even if you are impatient, please read the following two
181 paragraphs carefully before you install OpenSSL.
183 For security reasons the default system location is by default not writable
184 for unprivileged users. So for the final installation step administrative
185 privileges are required. The default system location and the procedure to
186 obtain administrative privileges depends on the operating system.
187 It is recommended to compile and test OpenSSL with normal user privileges
188 and use administrative privileges only for the final installation step.
190 On some platforms OpenSSL is preinstalled as part of the Operating System.
191 In this case it is highly recommended not to overwrite the system versions,
192 because other applications or libraries might depend on it.
193 To avoid breaking other applications, install your copy of OpenSSL to a
194 [different location](#installing-to-a-different-location) which is not in
195 the global search path for system libraries.
197 Finally, if you plan on using the FIPS module, you need to read the
198 [Post-installation Notes](#post-installation-notes) further down.
200 ### Unix / Linux / macOS
202 Depending on your distribution, you need to run the following command as
203 root user or prepend `sudo` to the command:
207 By default, OpenSSL will be installed to
211 More precisely, the files will be installed into the subdirectories
218 depending on the file type, as it is custom on Unix-like operating systems.
222 Use the following command to install OpenSSL.
226 By default, OpenSSL will be installed to
232 If you are using Visual Studio, open the Developer Command Prompt _elevated_
233 and issue the following command.
237 The easiest way to elevate the Command Prompt is to press and hold down
238 the both the `<CTRL>` and `<SHIFT>` key while clicking the menu item in the
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 Seeding the Random Generator
444 ----------------------------
446 --with-rand-seed=seed1[,seed2,...]
448 A comma separated list of seeding methods which will be tried by OpenSSL
449 in order to obtain random input (a.k.a "entropy") for seeding its
450 cryptographically secure random number generator (CSPRNG).
451 The current seeding methods are:
455 Use a trusted operating system entropy source.
456 This is the default method if such an entropy source exists.
460 Use the [getrandom(2)][man-getrandom] or equivalent system call.
462 [man-getrandom]: http://man7.org/linux/man-pages/man2/getrandom.2.html
466 Use the first device from the `DEVRANDOM` list which can be opened to read
467 random bytes. The `DEVRANDOM` preprocessor constant expands to
469 "/dev/urandom","/dev/random","/dev/srandom"
471 on most unix-ish operating systems.
475 Check for an entropy generating daemon.
476 This source is ignored by the FIPS provider.
480 Use the `RDSEED` or `RDRAND` command on x86 or `RNDRRS` command on aarch64
481 if provided by the CPU.
485 Use librandom (not implemented yet).
486 This source is ignored by the FIPS provider.
490 Disable automatic seeding. This is the default on some operating systems where
491 no suitable entropy source exists, or no support for it is implemented yet.
492 This option is ignored by the FIPS provider.
494 For more information, see the section [Notes on random number generation][rng]
495 at the end of this document.
497 [rng]: #notes-on-random-number-generation
499 Setting the FIPS HMAC key
500 -------------------------
504 As part of its self-test validation, the FIPS module must verify itself
505 by performing a SHA-256 HMAC computation on itself. The default key is
506 the SHA256 value of "the holy handgrenade of antioch" and is sufficient
507 for meeting the FIPS requirements.
509 To change the key to a different value, use this flag. The value should
510 be a hex string no more than 64 characters.
512 Enable and Disable Features
513 ---------------------------
515 Feature options always come in pairs, an option to enable feature
516 `xxxx`, and an option to disable it:
518 [ enable-xxxx | no-xxxx ]
520 Whether a feature is enabled or disabled by default, depends on the feature.
521 In the following list, always the non-default variant is documented: if
522 feature `xxxx` is disabled by default then `enable-xxxx` is documented and
523 if feature `xxxx` is enabled by default then `no-xxxx` is documented.
527 Don't build the AFALG engine.
529 This option will be forced on a platform that does not support AFALG.
533 Build with Kernel TLS support.
535 This option will enable the use of the Kernel TLS data-path, which can improve
536 performance and allow for the use of sendfile and splice system calls on
537 TLS sockets. The Kernel may use TLS accelerators if any are available on the
538 system. This option will be forced off on systems that do not support the
539 Kernel TLS data-path.
543 Build with the Address sanitiser.
545 This is a developer option only. It may not work on all platforms and should
546 never be used in production environments. It will only work when used with
547 gcc or clang and should be used in conjunction with the [no-shared](#no-shared)
550 ### enable-acvp-tests
552 Build support for Automated Cryptographic Validation Protocol (ACVP)
555 This is required for FIPS validation purposes. Certain ACVP tests require
556 access to algorithm internals that are not normally accessible.
557 Additional information related to ACVP can be found at
558 <https://github.com/usnistgov/ACVP>.
562 Do not use assembler code.
564 This should be viewed as debugging/troubleshooting option rather than for
565 production use. On some platforms a small amount of assembler code may still
566 be used even with this option.
570 Do not build support for async operations.
574 Don't automatically load all supported ciphers and digests.
576 Typically OpenSSL will make available all of its supported ciphers and digests.
577 For a statically linked application this may be undesirable if small executable
578 size is an objective. This only affects libcrypto. Ciphers and digests will
579 have to be loaded manually using `EVP_add_cipher()` and `EVP_add_digest()`
580 if this option is used. This option will force a non-shared build.
584 Don't automatically load all libcrypto/libssl error strings.
586 Typically OpenSSL will automatically load human readable error strings. For a
587 statically linked application this may be undesirable if small executable size
592 Build with support for brotli compression/decompression.
594 ### enable-brotli-dynamic
596 Like the enable-brotli option, but has OpenSSL load the brotli library dynamically
599 This is only supported on systems where loading of shared libraries is supported.
601 ### no-autoload-config
603 Don't automatically load the default `openssl.cnf` file.
605 Typically OpenSSL will automatically load a system config file which configures
608 ### enable-buildtest-c++
610 While testing, generate C++ buildtest files that simply check that the public
611 OpenSSL header files are usable standalone with C++.
613 Enabling this option demands extra care. For any compiler flag given directly
614 as configuration option, you must ensure that it's valid for both the C and
615 the C++ compiler. If not, the C++ build test will most likely break. As an
616 alternative, you can use the language specific variables, `CFLAGS` and `CXXFLAGS`.
620 Use the specified text instead of the default banner at the end of
625 On platforms where the choice of 32-bit or 64-bit architecture
626 is not explicitly specified, `Configure` will print a warning
627 message and wait for a few seconds to let you interrupt the
628 configuration. Using this flag skips the wait.
632 Build only some minimal set of features.
633 This is a developer option used internally for CI build tests of the project.
637 Never cache algorithms when they are fetched from a provider. Normally, a
638 provider indicates if the algorithms it supplies can be cached or not. Using
639 this option will reduce run-time memory usage but it also introduces a
640 significant performance penalty. This option is primarily designed to help
641 with detecting incorrect reference counting.
645 Don't build the CAPI engine.
647 This option will be forced if on a platform that does not support CAPI.
651 Don't build support for Certificate Management Protocol (CMP)
652 and Certificate Request Message Format (CRMF).
656 Don't build support for Cryptographic Message Syntax (CMS).
660 Don't build support for SSL/TLS compression.
662 If this option is enabled (the default), then compression will only work if
663 the zlib or `zlib-dynamic` options are also chosen.
665 ### enable-crypto-mdebug
667 This now only enables the `failed-malloc` feature.
669 ### enable-crypto-mdebug-backtrace
671 This is a no-op; the project uses the compiler's address/leak sanitizer instead.
675 Don't build support for Certificate Transparency (CT).
679 Don't build with support for deprecated APIs up until and including the version
680 given with `--api` (or the current version, if `--api` wasn't specified).
684 Don't build support for datagram based BIOs.
686 Selecting this option will also force the disabling of DTLS.
690 Don't build support for loading Dynamic Shared Objects (DSO)
692 ### enable-devcryptoeng
694 Build the `/dev/crypto` engine.
696 This option is automatically selected on the BSD platform, in which case it can
697 be disabled with `no-devcryptoeng`.
699 ### no-dynamic-engine
701 Don't build the dynamically loaded engines.
703 This only has an effect in a shared build.
707 Don't build support for Elliptic Curves.
711 Don't build support for binary Elliptic Curves
713 ### enable-ec_nistp_64_gcc_128
715 Enable support for optimised implementations of some commonly used NIST
718 This option is only supported on platforms:
720 - with little-endian storage of non-byte types
721 - that tolerate misaligned memory references
722 - where the compiler:
723 - supports the non-standard type `__uint128_t`
724 - defines the built-in macro `__SIZEOF_INT128__`
728 Build support for gathering entropy from the Entropy Gathering Daemon (EGD).
732 Don't build support for loading engines.
736 Don't compile in any error strings.
738 ### enable-external-tests
740 Enable building of integration with external test suites.
742 This is a developer option and may not work on all platforms. The following
743 external test suites are currently supported:
745 - GOST engine test suite
746 - Python PYCA/Cryptography test suite
749 See the file [test/README-external.md](test/README-external.md)
754 Don't compile in filename and line number information (e.g. for errors and
759 Build (and install) the FIPS provider
761 ### no-fips-securitychecks
763 Don't perform FIPS module run-time checks related to enforcement of security
764 parameters such as minimum security strength of keys.
766 ### enable-fuzz-libfuzzer, enable-fuzz-afl
768 Build with support for fuzzing using either libfuzzer or AFL.
770 These are developer options only. They may not work on all platforms and
771 should never be used in production environments.
773 See the file [fuzz/README.md](fuzz/README.md) for further details.
777 Don't build support for GOST based ciphersuites.
779 Note that if this feature is enabled then GOST ciphersuites are only available
780 if the GOST algorithms are also available through loading an externally supplied
785 Don't build the legacy provider.
787 Disabling this also disables the legacy algorithms: MD2 (already disabled by default).
791 Don't generate dependencies.
795 Don't build any dynamically loadable engines.
797 This also implies `no-dynamic-engine`.
801 Don't build support for writing multiple records in one go in libssl
803 Note: this is a different capability to the pipelining functionality.
807 Don't build support for the Next Protocol Negotiation (NPN) TLS extension.
811 Don't build support for Online Certificate Status Protocol (OCSP).
815 Don't build the padlock engine.
819 As synonym for `no-padlockeng`. Deprecated and should not be used.
823 Don't build with support for Position Independent Code.
827 Don't pin the shared libraries.
829 By default OpenSSL will attempt to stay in memory until the process exits.
830 This is so that libcrypto and libssl can be properly cleaned up automatically
831 via an `atexit()` handler. The handler is registered by libcrypto and cleans
832 up both libraries. On some platforms the `atexit()` handler will run on unload of
833 libcrypto (if it has been dynamically loaded) rather than at process exit. This
834 option can be used to stop OpenSSL from attempting to stay in memory until the
835 process exits. This could lead to crashes if either libcrypto or libssl have
836 already been unloaded at the point that the atexit handler is invoked, e.g. on a
837 platform which calls `atexit()` on unload of the library, and libssl is unloaded
838 before libcrypto then a crash is likely to happen. Applications can suppress
839 running of the `atexit()` handler at run time by using the
840 `OPENSSL_INIT_NO_ATEXIT` option to `OPENSSL_init_crypto()`.
841 See the man page for it for further details.
845 Don't use POSIX IO capabilities.
849 Don't build support for Pre-Shared Key based ciphersuites.
853 Don't use hardware RDRAND capabilities.
857 Don't build support for RFC3779, "X.509 Extensions for IP Addresses and
862 Build support for Stream Control Transmission Protocol (SCTP).
866 Do not create shared libraries, only static ones.
868 See [Notes on shared libraries](#notes-on-shared-libraries) below.
872 Don't build support for socket BIOs.
876 Don't build support for Secure Remote Password (SRP) protocol or
877 SRP based ciphersuites.
881 Don't build Secure Real-Time Transport Protocol (SRTP) support.
885 Exclude SSE2 code paths from 32-bit x86 assembly modules.
887 Normally SSE2 extension is detected at run-time, but the decision whether or not
888 the machine code will be executed is taken solely on CPU capability vector. This
889 means that if you happen to run OS kernel which does not support SSE2 extension
890 on Intel P4 processor, then your application might be exposed to "illegal
891 instruction" exception. There might be a way to enable support in kernel, e.g.
892 FreeBSD kernel can be compiled with `CPU_ENABLE_SSE`, and there is a way to
893 disengage SSE2 code paths upon application start-up, but if you aim for wider
894 "audience" running such kernel, consider `no-sse2`. Both the `386` and `no-asm`
895 options imply `no-sse2`.
899 Don't build with SSL Trace capabilities.
901 This removes the `-trace` option from `s_client` and `s_server`, and omits the
902 `SSL_trace()` function from libssl.
904 Disabling `ssl-trace` may provide a small reduction in libssl binary size.
908 Don't build the statically linked engines.
910 This only has an impact when not built "shared".
914 Don't use anything from the C header file `stdio.h` that makes use of the `FILE`
915 type. Only libcrypto and libssl can be built in this way. Using this option will
916 suppress building the command line applications. Additionally, since the OpenSSL
917 tests also use the command line applications, the tests will also be skipped.
921 Don't build test programs or run any tests.
925 Build with support for TCP Fast Open (RFC7413). Supported on Linux, macOS and FreeBSD.
929 Build with QUIC support. This is currently just for developers as the
930 implementation is by no means complete and usable.
934 Don't build with support for multi-threaded applications.
938 Build with support for multi-threaded applications. Most platforms will enable
939 this by default. However, if on a platform where this is not the case then this
940 will usually require additional system-dependent options!
942 See [Notes on multi-threading](#notes-on-multi-threading) below.
946 Don't build with support for thread pool functionality.
950 Build with thread pool functionality. If enabled, OpenSSL algorithms may
951 use the thread pool to perform parallel computation. This option in itself
952 does not enable OpenSSL to spawn new threads. Currently the only supported
953 thread pool mechanism is the default thread pool.
955 ### no-default-thread-pool
957 Don't build with support for default thread pool functionality.
959 ### default-thread-pool
961 Build with default thread pool functionality. If enabled, OpenSSL may create
962 and manage threads up to a maximum number of threads authorized by the
963 application. Supported on POSIX compliant platforms and Windows.
967 Build with support for the integrated tracing api.
969 See manual pages OSSL_trace_set_channel(3) and OSSL_trace_enabled(3) for details.
973 Don't build Time Stamping (TS) Authority support.
977 Build with the Undefined Behaviour sanitiser (UBSAN).
979 This is a developer option only. It may not work on all platforms and should
980 never be used in production environments. It will only work when used with
981 gcc or clang and should be used in conjunction with the `-DPEDANTIC` option
982 (or the `--strict-warnings` option).
986 Don't build with the User Interface (UI) console method
988 The User Interface console method enables text based console prompts.
992 Enable additional unit test APIs.
994 This should not typically be used in production deployments.
998 Don't build support for UPLINK interface.
1000 ### enable-weak-ssl-ciphers
1002 Build support for SSL/TLS ciphers that are considered "weak"
1004 Enabling this includes for example the RC4 based ciphersuites.
1008 Build with support for zlib compression/decompression.
1012 Like the zlib option, but has OpenSSL load the zlib library dynamically
1015 This is only supported on systems where loading of shared libraries is supported.
1019 In 32-bit x86 builds, use the 80386 instruction set only in assembly modules
1021 The default x86 code is more efficient, but requires at least an 486 processor.
1022 Note: This doesn't affect compiler generated code, so this option needs to be
1023 accompanied by a corresponding compiler-specific option.
1027 no-{ssl|ssl3|tls|tls1|tls1_1|tls1_2|tls1_3|dtls|dtls1|dtls1_2}
1029 Don't build support for negotiating the specified SSL/TLS protocol.
1031 If `no-tls` is selected then all of `tls1`, `tls1_1`, `tls1_2` and `tls1_3`
1033 Similarly `no-dtls` will disable `dtls1` and `dtls1_2`. The `no-ssl` option is
1034 synonymous with `no-ssl3`. Note this only affects version negotiation.
1035 OpenSSL will still provide the methods for applications to explicitly select
1036 the individual protocol versions.
1038 ### no-{protocol}-method
1040 no-{ssl3|tls1|tls1_1|tls1_2|dtls1|dtls1_2}-method
1042 Analogous to `no-{protocol}` but in addition do not build the methods for
1043 applications to explicitly select individual protocol versions. Note that there
1044 is no `no-tls1_3-method` option because there is no application method for
1047 Using individual protocol methods directly is deprecated. Applications should
1048 use `TLS_method()` instead.
1050 ### enable-{algorithm}
1054 Build with support for the specified algorithm.
1058 no-{aria|bf|blake2|camellia|cast|chacha|cmac|
1059 des|dh|dsa|ecdh|ecdsa|idea|md4|mdc2|ocb|
1060 poly1305|rc2|rc4|rmd160|scrypt|seed|
1061 siphash|siv|sm2|sm3|sm4|whirlpool}
1063 Build without support for the specified algorithm.
1065 The `ripemd` algorithm is deprecated and if used is synonymous with `rmd160`.
1067 ### Compiler-specific options
1069 -Dxxx, -Ixxx, -Wp, -lxxx, -Lxxx, -Wl, -rpath, -R, -framework, -static
1071 These system specific options will be recognised and passed through to the
1072 compiler to allow you to define preprocessor symbols, specify additional
1073 libraries, library directories or other compiler options. It might be worth
1074 noting that some compilers generate code specifically for processor the
1075 compiler currently executes on. This is not necessarily what you might have
1076 in mind, since it might be unsuitable for execution on other, typically older,
1077 processor. Consult your compiler documentation.
1079 Take note of the [Environment Variables](#environment-variables) documentation
1080 below and how these flags interact with those variables.
1084 Additional options that are not otherwise recognised are passed through as
1085 they are to the compiler as well. Unix-style options beginning with a
1086 `-` or `+` and Windows-style options beginning with a `/` are recognised.
1087 Again, consult your compiler documentation.
1089 If the option contains arguments separated by spaces, then the URL-style
1090 notation `%20` can be used for the space character in order to avoid having
1091 to quote the option. For example, `-opt%20arg` gets expanded to `-opt arg`.
1092 In fact, any ASCII character can be encoded as %xx using its hexadecimal
1095 Take note of the [Environment Variables](#environment-variables) documentation
1096 below and how these flags interact with those variables.
1098 ### Environment Variables
1102 Assign the given value to the environment variable `VAR` for `Configure`.
1104 These work just like normal environment variable assignments, but are supported
1105 on all platforms and are confined to the configuration scripts only.
1106 These assignments override the corresponding value in the inherited environment,
1109 The following variables are used as "`make` variables" and can be used as an
1110 alternative to giving preprocessor, compiler and linker options directly as
1111 configuration. The following variables are supported:
1113 AR The static library archiver.
1114 ARFLAGS Flags for the static library archiver.
1115 AS The assembler compiler.
1116 ASFLAGS Flags for the assembler compiler.
1118 CFLAGS Flags for the C compiler.
1119 CXX The C++ compiler.
1120 CXXFLAGS Flags for the C++ compiler.
1121 CPP The C/C++ preprocessor.
1122 CPPFLAGS Flags for the C/C++ preprocessor.
1123 CPPDEFINES List of CPP macro definitions, separated
1124 by a platform specific character (':' or
1125 space for Unix, ';' for Windows, ',' for
1126 VMS). This can be used instead of using
1127 -D (or what corresponds to that on your
1128 compiler) in CPPFLAGS.
1129 CPPINCLUDES List of CPP inclusion directories, separated
1130 the same way as for CPPDEFINES. This can
1131 be used instead of -I (or what corresponds
1132 to that on your compiler) in CPPFLAGS.
1133 HASHBANGPERL Perl invocation to be inserted after '#!'
1134 in public perl scripts (only relevant on
1136 LD The program linker (not used on Unix, $(CC)
1138 LDFLAGS Flags for the shared library, DSO and
1140 LDLIBS Extra libraries to use when linking.
1141 Takes the form of a space separated list
1142 of library specifications on Unix and
1143 Windows, and as a comma separated list of
1145 RANLIB The library archive indexer.
1146 RC The Windows resource compiler.
1147 RCFLAGS Flags for the Windows resource compiler.
1148 RM The command to remove files and directories.
1150 These cannot be mixed with compiling/linking flags given on the command line.
1151 In other words, something like this isn't permitted.
1153 $ ./Configure -DFOO CPPFLAGS=-DBAR -DCOOKIE
1155 Backward compatibility note:
1157 To be compatible with older configuration scripts, the environment variables
1158 are ignored if compiling/linking flags are given on the command line, except
1161 AR, CC, CXX, CROSS_COMPILE, HASHBANGPERL, PERL, RANLIB, RC, and WINDRES
1163 For example, the following command will not see `-DBAR`:
1165 $ CPPFLAGS=-DBAR ./Configure -DCOOKIE
1167 However, the following will see both set variables:
1169 $ CC=gcc CROSS_COMPILE=x86_64-w64-mingw32- ./Configure -DCOOKIE
1171 If `CC` is set, it is advisable to also set `CXX` to ensure both the C and C++
1172 compiler are in the same "family". This becomes relevant with
1173 `enable-external-tests` and `enable-buildtest-c++`.
1180 Reconfigure from earlier data.
1182 This fetches the previous command line options and environment from data
1183 saved in `configdata.pm` and runs the configuration process again, using
1184 these options and environment. Note: NO other option is permitted together
1185 with `reconf`. Note: The original configuration saves away values for ALL
1186 environment variables that were used, and if they weren't defined, they are
1187 still saved away with information that they weren't originally defined.
1188 This information takes precedence over environment variables that are
1189 defined when reconfiguring.
1191 Displaying configuration data
1192 -----------------------------
1194 The configuration script itself will say very little, and finishes by
1195 creating `configdata.pm`. This perl module can be loaded by other scripts
1196 to find all the configuration data, and it can also be used as a script to
1197 display all sorts of configuration data in a human readable form.
1199 For more information, please do:
1201 $ ./configdata.pm --help # Unix
1205 $ perl configdata.pm --help # Windows and VMS
1207 Installation Steps in Detail
1208 ============================
1213 ### Automatic Configuration
1215 In previous version, the `config` script determined the platform type and
1216 compiler and then called `Configure`. Starting with this release, they are
1219 #### Unix / Linux / macOS
1221 $ ./Configure [options...]
1225 $ perl Configure [options...]
1229 $ perl Configure [options...]
1231 ### Manual Configuration
1233 OpenSSL knows about a range of different operating system, hardware and
1234 compiler combinations. To see the ones it knows about, run
1236 $ ./Configure LIST # Unix
1240 $ perl Configure LIST # All other platforms
1242 For the remainder of this text, the Unix form will be used in all examples.
1243 Please use the appropriate form for your platform.
1245 Pick a suitable name from the list that matches your system. For most
1246 operating systems there is a choice between using cc or gcc.
1247 When you have identified your system (and if necessary compiler) use this
1248 name as the argument to `Configure`. For example, a `linux-elf` user would
1251 $ ./Configure linux-elf [options...]
1253 ### Creating your own Configuration
1255 If your system isn't listed, you will have to create a configuration
1256 file named `Configurations/YOURFILENAME.conf` (replace `YOURFILENAME`
1257 with a filename of your choosing) and add the correct
1258 configuration for your system. See the available configs as examples
1259 and read [Configurations/README.md](Configurations/README.md) and
1260 [Configurations/README-design.md](Configurations/README-design.md)
1261 for more information.
1263 The generic configurations `cc` or `gcc` should usually work on 32 bit
1266 `Configure` creates a build file (`Makefile` on Unix, `makefile` on Windows
1267 and `descrip.mms` on OpenVMS) from a suitable template in `Configurations/`,
1268 and defines various macros in `include/openssl/configuration.h` (generated
1269 from `include/openssl/configuration.h.in`.
1271 ### Out of Tree Builds
1273 OpenSSL can be configured to build in a build directory separate from the
1274 source code directory. It's done by placing yourself in some other
1275 directory and invoking the configuration commands from there.
1279 $ mkdir /var/tmp/openssl-build
1280 $ cd /var/tmp/openssl-build
1281 $ /PATH/TO/OPENSSL/SOURCE/Configure [options...]
1283 #### OpenVMS example
1285 $ set default sys$login:
1286 $ create/dir [.tmp.openssl-build]
1287 $ set default [.tmp.openssl-build]
1288 $ perl D:[PATH.TO.OPENSSL.SOURCE]Configure [options...]
1290 #### Windows example
1293 $ mkdir \temp-openssl
1295 $ perl d:\PATH\TO\OPENSSL\SOURCE\Configure [options...]
1297 Paths can be relative just as well as absolute. `Configure` will do its best
1298 to translate them to relative paths whenever possible.
1303 Build OpenSSL by running:
1306 $ mms ! (or mmk) OpenVMS
1309 This will build the OpenSSL libraries (`libcrypto.a` and `libssl.a` on
1310 Unix, corresponding on other platforms) and the OpenSSL binary
1311 (`openssl`). The libraries will be built in the top-level directory,
1312 and the binary will be in the `apps/` subdirectory.
1314 If the build fails, take a look at the [Build Failures](#build-failures)
1315 subsection of the [Troubleshooting](#troubleshooting) section.
1320 After a successful build, and before installing, the libraries should
1324 $ mms test ! OpenVMS
1325 $ nmake test # Windows
1327 **Warning:** you MUST run the tests from an unprivileged account (or disable
1328 your privileges temporarily if your platform allows it).
1330 See [test/README.md](test/README.md) for further details how run tests.
1332 See [test/README-dev.md](test/README-dev.md) for guidelines on adding tests.
1337 If everything tests ok, install OpenSSL with
1339 $ make install # Unix
1340 $ mms install ! OpenVMS
1341 $ nmake install # Windows
1343 Note that in order to perform the install step above you need to have
1344 appropriate permissions to write to the installation directory.
1346 The above commands will install all the software components in this
1347 directory tree under `<PREFIX>` (the directory given with `--prefix` or
1350 ### Unix / Linux / macOS
1352 bin/ Contains the openssl binary and a few other
1355 Contains the header files needed if you want
1356 to build your own programs that use libcrypto
1358 lib Contains the OpenSSL library files.
1359 lib/engines Contains the OpenSSL dynamically loadable engines.
1361 share/man/man1 Contains the OpenSSL command line man-pages.
1362 share/man/man3 Contains the OpenSSL library calls man-pages.
1363 share/man/man5 Contains the OpenSSL configuration format man-pages.
1364 share/man/man7 Contains the OpenSSL other misc man-pages.
1366 share/doc/openssl/html/man1
1367 share/doc/openssl/html/man3
1368 share/doc/openssl/html/man5
1369 share/doc/openssl/html/man7
1370 Contains the HTML rendition of the man-pages.
1374 'arch' is replaced with the architecture name, `ALPHA` or `IA64`,
1375 'sover' is replaced with the shared library version (`0101` for 1.1), and
1376 'pz' is replaced with the pointer size OpenSSL was built with:
1378 [.EXE.'arch'] Contains the openssl binary.
1379 [.EXE] Contains a few utility scripts.
1381 Contains the header files needed if you want
1382 to build your own programs that use libcrypto
1384 [.LIB.'arch'] Contains the OpenSSL library files.
1385 [.ENGINES'sover''pz'.'arch']
1386 Contains the OpenSSL dynamically loadable engines.
1387 [.SYS$STARTUP] Contains startup, login and shutdown scripts.
1388 These define appropriate logical names and
1390 [.SYSTEST] Contains the installation verification procedure.
1391 [.HTML] Contains the HTML rendition of the manual pages.
1393 ### Additional Directories
1395 Additionally, install will add the following directories under
1396 OPENSSLDIR (the directory given with `--openssldir` or its default)
1397 for you convenience:
1399 certs Initially empty, this is the default location
1400 for certificate files.
1401 private Initially empty, this is the default location
1402 for private key files.
1403 misc Various scripts.
1405 The installation directory should be appropriately protected to ensure
1406 unprivileged users cannot make changes to OpenSSL binaries or files, or
1407 install engines. If you already have a pre-installed version of OpenSSL as
1408 part of your Operating System it is recommended that you do not overwrite
1409 the system version and instead install to somewhere else.
1411 Package builders who want to configure the library for standard locations,
1412 but have the package installed somewhere else so that it can easily be
1415 $ make DESTDIR=/tmp/package-root install # Unix
1416 $ mms/macro="DESTDIR=TMP:[PACKAGE-ROOT]" install ! OpenVMS
1418 The specified destination directory will be prepended to all installation
1421 Compatibility issues with previous OpenSSL versions
1422 ---------------------------------------------------
1424 ### COMPILING existing applications
1426 Starting with version 1.1.0, OpenSSL hides a number of structures that were
1427 previously open. This includes all internal libssl structures and a number
1428 of EVP types. Accessor functions have been added to allow controlled access
1429 to the structures' data.
1431 This means that some software needs to be rewritten to adapt to the new ways
1432 of doing things. This often amounts to allocating an instance of a structure
1433 explicitly where you could previously allocate them on the stack as automatic
1434 variables, and using the provided accessor functions where you would previously
1435 access a structure's field directly.
1437 Some APIs have changed as well. However, older APIs have been preserved when
1440 Post-installation Notes
1441 -----------------------
1443 With the default OpenSSL installation comes a FIPS provider module, which
1444 needs some post-installation attention, without which it will not be usable.
1445 This involves using the following command:
1447 $ openssl fipsinstall
1449 See the openssl-fipsinstall(1) manual for details and examples.
1451 Advanced Build Options
1452 ======================
1454 Environment Variables
1455 ---------------------
1457 A number of environment variables can be used to provide additional control
1458 over the build process. Typically these should be defined prior to running
1459 `Configure`. Not all environment variables are relevant to all platforms.
1462 The name of the ar executable to use.
1465 Use a different build file name than the platform default
1466 ("Makefile" on Unix-like platforms, "makefile" on native Windows,
1467 "descrip.mms" on OpenVMS). This requires that there is a
1468 corresponding build file template.
1469 See [Configurations/README.md](Configurations/README.md)
1470 for further information.
1473 The compiler to use. Configure will attempt to pick a default
1474 compiler for your platform but this choice can be overridden
1475 using this variable. Set it to the compiler executable you wish
1476 to use, e.g. gcc or clang.
1479 This environment variable has the same meaning as for the
1480 "--cross-compile-prefix" Configure flag described above. If both
1481 are set then the Configure flag takes precedence.
1484 The command string for the Perl executable to insert in the
1485 #! line of perl scripts that will be publicly installed.
1486 Default: /usr/bin/env perl
1487 Note: the value of this variable is added to the same scripts
1488 on all platforms, but it's only relevant on Unix-like platforms.
1491 This can be the value `32` or `64` to specify the architecture
1492 when it is not "obvious" to the configuration. It should generally
1493 not be necessary to specify this environment variable.
1496 The name of the nm executable to use.
1498 OPENSSL_LOCAL_CONFIG_DIR
1499 OpenSSL comes with a database of information about how it
1500 should be built on different platforms as well as build file
1501 templates for those platforms. The database is comprised of
1502 ".conf" files in the Configurations directory. The build
1503 file templates reside there as well as ".tmpl" files. See the
1504 file [Configurations/README.md](Configurations/README.md)
1505 for further information about the format of ".conf" files
1506 as well as information on the ".tmpl" files.
1507 In addition to the standard ".conf" and ".tmpl" files, it is
1508 possible to create your own ".conf" and ".tmpl" files and
1509 store them locally, outside the OpenSSL source tree.
1510 This environment variable can be set to the directory where
1511 these files are held and will be considered by Configure
1512 before it looks in the standard directories.
1515 The name of the Perl executable to use when building OpenSSL.
1516 Only needed if builing should use a different Perl executable
1517 than what is used to run the Configure script.
1520 The name of the ranlib executable to use.
1523 The name of the rc executable to use. The default will be as
1524 defined for the target platform in the ".conf" file. If not
1525 defined then "windres" will be used. The WINDRES environment
1526 variable is synonymous to this. If both are defined then RC
1535 The `Configure` script generates a Makefile in a format relevant to the specific
1536 platform. The Makefiles provide a number of targets that can be used. Not all
1537 targets may be available on all platforms. Only the most common targets are
1538 described here. Examine the Makefiles themselves for the full list.
1541 The target to build all the software components and
1545 Build all the software components.
1546 THIS IS THE DEFAULT TARGET.
1549 Build all documentation components.
1552 Remove all build artefacts and return the directory to a "clean"
1556 Rebuild the dependencies in the Makefiles. This is a legacy
1557 option that no longer needs to be used since OpenSSL 1.1.0.
1560 Install all OpenSSL components.
1563 Only install the OpenSSL software components.
1566 Only install the OpenSSL documentation components.
1569 Only install the OpenSSL man pages (Unix only).
1572 Only install the OpenSSL HTML documentation.
1575 Install the FIPS provider module configuration file.
1578 Prints a list of all the self test names.
1581 Build and run the OpenSSL self tests.
1584 Uninstall all OpenSSL components.
1588 Re-run the configuration process, as exactly as the last time
1592 This is a developer option. If you are developing a patch for
1593 OpenSSL you may need to use this if you want to update
1594 automatically generated files; add new error codes or add new
1595 (or change the visibility of) public API functions. (Unix only).
1597 Running Selected Tests
1598 ----------------------
1600 You can specify a set of tests to be performed
1601 using the `make` variable `TESTS`.
1603 See the section [Running Selected Tests of
1604 test/README.md](test/README.md#running-selected-tests).
1609 Configuration Problems
1610 ----------------------
1612 ### Selecting the correct target
1614 The `./Configure` script tries hard to guess your operating system, but in some
1615 cases it does not succeed. You will see a message like the following:
1618 Operating system: x86-whatever-minix
1619 This system (minix) is not supported. See file INSTALL.md for details.
1621 Even if the automatic target selection by the `./Configure` script fails,
1622 chances are that you still might find a suitable target in the `Configurations`
1623 directory, which you can supply to the `./Configure` command,
1624 possibly after some adjustment.
1626 The `Configurations/` directory contains a lot of examples of such targets.
1627 The main configuration file is [10-main.conf], which contains all targets that
1628 are officially supported by the OpenSSL team. Other configuration files contain
1629 targets contributed by other OpenSSL users. The list of targets can be found in
1630 a Perl list `my %targets = ( ... )`.
1635 inherit_from => [ "base-target" ],
1637 cflags => add("..."),
1639 perlasm_scheme => "...",
1644 If you call `./Configure` without arguments, it will give you a list of all
1645 known targets. Using `grep`, you can lookup the target definition in the
1646 `Configurations/` directory. For example the `android-x86_64` can be found in
1647 [Configurations/15-android.conf](Configurations/15-android.conf).
1649 The directory contains two README files, which explain the general syntax and
1650 design of the configuration files.
1652 - [Configurations/README.md](Configurations/README.md)
1653 - [Configurations/README-design.md](Configurations/README-design.md)
1655 If you need further help, try to search the [openssl-users] mailing list
1656 or the [GitHub Issues] for existing solutions. If you don't find anything,
1657 you can [raise an issue] to ask a question yourself.
1659 More about our support resources can be found in the [SUPPORT] file.
1661 ### Configuration Errors
1663 If the `./Configure` or `./Configure` command fails with an error message,
1664 read the error message carefully and try to figure out whether you made
1665 a mistake (e.g., by providing a wrong option), or whether the script is
1666 working incorrectly. If you think you encountered a bug, please
1667 [raise an issue] on GitHub to file a bug report.
1669 Along with a short description of the bug, please provide the complete
1670 configure command line and the relevant output including the error message.
1672 Note: To make the output readable, please add a 'code fence' (three backquotes
1673 ` ``` ` on a separate line) before and after your output:
1676 ./Configure [your arguments...]
1685 If the build fails, look carefully at the output. Try to locate and understand
1686 the error message. It might be that the compiler is already telling you
1687 exactly what you need to do to fix your problem.
1689 There may be reasons for the failure that aren't problems in OpenSSL itself,
1690 for example if the compiler reports missing standard or third party headers.
1692 If the build succeeded previously, but fails after a source or configuration
1693 change, it might be helpful to clean the build tree before attempting another
1694 build. Use this command:
1697 $ mms clean ! (or mmk) OpenVMS
1698 $ nmake clean # Windows
1700 Assembler error messages can sometimes be sidestepped by using the `no-asm`
1701 configuration option. See also [notes](#notes-on-assembler-modules-compilation).
1703 Compiling parts of OpenSSL with gcc and others with the system compiler will
1704 result in unresolved symbols on some systems.
1706 If you are still having problems, try to search the [openssl-users] mailing
1707 list or the [GitHub Issues] for existing solutions. If you think you
1708 encountered an OpenSSL bug, please [raise an issue] to file a bug report.
1709 Please take the time to review the existing issues first; maybe the bug was
1710 already reported or has already been fixed.
1715 If some tests fail, look at the output. There may be reasons for the failure
1716 that isn't a problem in OpenSSL itself (like an OS malfunction or a Perl issue).
1718 You may want increased verbosity, that can be accomplished as described in
1719 section [Test Failures of test/README.md](test/README.md#test-failures).
1721 You may also want to selectively specify which test(s) to perform. This can be
1722 done using the `make` variable `TESTS` as described in section [Running
1723 Selected Tests of test/README.md](test/README.md#running-selected-tests).
1725 If you find a problem with OpenSSL itself, try removing any
1726 compiler optimization flags from the `CFLAGS` line in the Makefile and
1727 run `make clean; make` or corresponding.
1729 To report a bug please open an issue on GitHub, at
1730 <https://github.com/openssl/openssl/issues>.
1735 Notes on multi-threading
1736 ------------------------
1738 For some systems, the OpenSSL `Configure` script knows what compiler options
1739 are needed to generate a library that is suitable for multi-threaded
1740 applications. On these systems, support for multi-threading is enabled
1741 by default; use the `no-threads` option to disable (this should never be
1744 On other systems, to enable support for multi-threading, you will have
1745 to specify at least two options: `threads`, and a system-dependent option.
1746 (The latter is `-D_REENTRANT` on various systems.) The default in this
1747 case, obviously, is not to include support for multi-threading (but
1748 you can still use `no-threads` to suppress an annoying warning message
1749 from the `Configure` script.)
1751 OpenSSL provides built-in support for two threading models: pthreads (found on
1752 most UNIX/Linux systems), and Windows threads. No other threading models are
1753 supported. If your platform does not provide pthreads or Windows threads then
1754 you should use `Configure` with the `no-threads` option.
1756 For pthreads, all locks are non-recursive. In addition, in a debug build,
1757 the mutex attribute `PTHREAD_MUTEX_ERRORCHECK` is used. If this is not
1758 available on your platform, you might have to add
1759 `-DOPENSSL_NO_MUTEX_ERRORCHECK` to your `Configure` invocation.
1760 (On Linux `PTHREAD_MUTEX_ERRORCHECK` is an enum value, so a built-in
1761 ifdef test cannot be used.)
1763 Notes on shared libraries
1764 -------------------------
1766 For most systems the OpenSSL `Configure` script knows what is needed to
1767 build shared libraries for libcrypto and libssl. On these systems
1768 the shared libraries will be created by default. This can be suppressed and
1769 only static libraries created by using the `no-shared` option. On systems
1770 where OpenSSL does not know how to build shared libraries the `no-shared`
1771 option will be forced and only static libraries will be created.
1773 Shared libraries are named a little differently on different platforms.
1774 One way or another, they all have the major OpenSSL version number as
1775 part of the file name, i.e. for OpenSSL 1.1.x, `1.1` is somehow part of
1778 On most POSIX platforms, shared libraries are named `libcrypto.so.1.1`
1779 and `libssl.so.1.1`.
1781 on Cygwin, shared libraries are named `cygcrypto-1.1.dll` and `cygssl-1.1.dll`
1782 with import libraries `libcrypto.dll.a` and `libssl.dll.a`.
1784 On Windows build with MSVC or using MingW, shared libraries are named
1785 `libcrypto-1_1.dll` and `libssl-1_1.dll` for 32-bit Windows,
1786 `libcrypto-1_1-x64.dll` and `libssl-1_1-x64.dll` for 64-bit x86_64 Windows,
1787 and `libcrypto-1_1-ia64.dll` and `libssl-1_1-ia64.dll` for IA64 Windows.
1788 With MSVC, the import libraries are named `libcrypto.lib` and `libssl.lib`,
1789 while with MingW, they are named `libcrypto.dll.a` and `libssl.dll.a`.
1791 On VMS, shareable images (VMS speak for shared libraries) are named
1792 `ossl$libcrypto0101_shr.exe` and `ossl$libssl0101_shr.exe`. However, when
1793 OpenSSL is specifically built for 32-bit pointers, the shareable images
1794 are named `ossl$libcrypto0101_shr32.exe` and `ossl$libssl0101_shr32.exe`
1795 instead, and when built for 64-bit pointers, they are named
1796 `ossl$libcrypto0101_shr64.exe` and `ossl$libssl0101_shr64.exe`.
1798 Notes on random number generation
1799 ---------------------------------
1801 Availability of cryptographically secure random numbers is required for
1802 secret key generation. OpenSSL provides several options to seed the
1803 internal CSPRNG. If not properly seeded, the internal CSPRNG will refuse
1804 to deliver random bytes and a "PRNG not seeded error" will occur.
1806 The seeding method can be configured using the `--with-rand-seed` option,
1807 which can be used to specify a comma separated list of seed methods.
1808 However, in most cases OpenSSL will choose a suitable default method,
1809 so it is not necessary to explicitly provide this option. Note also
1810 that not all methods are available on all platforms. The FIPS provider will
1811 silently ignore seed sources that were not validated.
1813 I) On operating systems which provide a suitable randomness source (in
1814 form of a system call or system device), OpenSSL will use the optimal
1815 available method to seed the CSPRNG from the operating system's
1816 randomness sources. This corresponds to the option `--with-rand-seed=os`.
1818 II) On systems without such a suitable randomness source, automatic seeding
1819 and reseeding is disabled (`--with-rand-seed=none`) and it may be necessary
1820 to install additional support software to obtain a random seed and reseed
1821 the CSPRNG manually. Please check out the manual pages for `RAND_add()`,
1822 `RAND_bytes()`, `RAND_egd()`, and the FAQ for more information.
1824 Notes on assembler modules compilation
1825 --------------------------------------
1827 Compilation of some code paths in assembler modules might depend on whether the
1828 current assembler version supports certain ISA extensions or not. Code paths
1829 that use the AES-NI, PCLMULQDQ, SSSE3, and SHA extensions are always assembled.
1830 Apart from that, the minimum requirements for the assembler versions are shown
1833 | ISA extension | GNU as | nasm | llvm |
1834 |---------------|--------|--------|---------|
1835 | AVX | 2.19 | 2.09 | 3.0 |
1836 | AVX2 | 2.22 | 2.10 | 3.1 |
1837 | ADCX/ADOX | 2.23 | 2.10 | 3.3 |
1838 | AVX512 | 2.25 | 2.11.8 | 3.6 (*) |
1839 | AVX512IFMA | 2.26 | 2.11.8 | 6.0 (*) |
1840 | VAES | 2.30 | 2.13.3 | 6.0 (*) |
1844 (*) Even though AVX512 support was implemented in llvm 3.6, prior to version 7.0
1845 an explicit -march flag was apparently required to compile assembly modules. But
1846 then the compiler generates processor-specific code, which in turn contradicts
1847 the idea of performing dispatch at run-time, which is facilitated by the special
1848 variable `OPENSSL_ia32cap`. For versions older than 7.0, it is possible to work
1849 around the problem by forcing the build procedure to use the following script:
1852 exec clang -no-integrated-as "$@"
1854 instead of the real clang. In which case it doesn't matter what clang version
1855 is used, as it is the version of the GNU assembler that will be checked.
1862 <https://mta.openssl.org/mailman/listinfo/openssl-users>
1868 <https://github.com/openssl/openssl/issues>
1871 <https://github.com/openssl/openssl/issues/new/choose>
1874 Configurations/10-main.conf