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 - [ZLib Flags](#zlib-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 **Mandatory arguments** are enclosed in double curly braces.
124 A simple example would be
126 $ type {{ filename }}
128 which is to be understood to use the command `type` on some file name
129 determined by the user.
131 **Optional Arguments** are enclosed in double square brackets.
135 Note that the notation assumes spaces around `{`, `}`, `[`, `]`, `{{`, `}}` and
136 `[[`, `]]`. This is to differentiate from OpenVMS directory
137 specifications, which also use [ and ], but without spaces.
139 Quick Installation Guide
140 ========================
142 If you just want to get OpenSSL installed without bothering too much
143 about the details, here is the short version of how to build and install
144 OpenSSL. If any of the following steps fails, please consult the
145 [Installation in Detail](#installation-steps-in-detail) section below.
150 Use the following commands to configure, build and test OpenSSL.
151 The testing is optional, but recommended if you intend to install
152 OpenSSL for production use.
154 ### Unix / Linux / macOS
162 Use the following commands to build OpenSSL:
170 If you are using Visual Studio, open a Developer Command Prompt and
171 issue the following commands to build OpenSSL.
177 As mentioned in the [Choices](#choices) section, you need to pick one
178 of the four Configure targets in the first command.
180 Most likely you will be using the `VC-WIN64A` target for 64bit Windows
181 binaries (AMD64) or `VC-WIN32` for 32bit Windows binaries (X86).
182 The other two options are `VC-WIN64I` (Intel IA64, Itanium) and
183 `VC-CE` (Windows CE) are rather uncommon nowadays.
188 The following commands will install OpenSSL to a default system location.
190 **Danger Zone:** even if you are impatient, please read the following two
191 paragraphs carefully before you install OpenSSL.
193 For security reasons the default system location is by default not writable
194 for unprivileged users. So for the final installation step administrative
195 privileges are required. The default system location and the procedure to
196 obtain administrative privileges depends on the operating system.
197 It is recommended to compile and test OpenSSL with normal user privileges
198 and use administrative privileges only for the final installation step.
200 On some platforms OpenSSL is preinstalled as part of the Operating System.
201 In this case it is highly recommended not to overwrite the system versions,
202 because other applications or libraries might depend on it.
203 To avoid breaking other applications, install your copy of OpenSSL to a
204 [different location](#installing-to-a-different-location) which is not in
205 the global search path for system libraries.
207 Finally, if you plan on using the FIPS module, you need to read the
208 [Post-installation Notes](#post-installation-notes) further down.
210 ### Unix / Linux / macOS
212 Depending on your distribution, you need to run the following command as
213 root user or prepend `sudo` to the command:
217 By default, OpenSSL will be installed to
221 More precisely, the files will be installed into the subdirectories
228 depending on the file type, as it is custom on Unix-like operating systems.
232 Use the following command to install OpenSSL.
236 By default, OpenSSL will be installed to
242 If you are using Visual Studio, open the Developer Command Prompt _elevated_
243 and issue the following command.
247 The easiest way to elevate the Command Prompt is to press and hold down
248 the both the `<CTRL>` and `<SHIFT>` key while clicking the menu item in the
251 The default installation location is
253 C:\Program Files\OpenSSL
255 for native binaries, or
257 C:\Program Files (x86)\OpenSSL
259 for 32bit binaries on 64bit Windows (WOW64).
261 #### Installing to a different location
263 To install OpenSSL to a different location (for example into your home
264 directory for testing purposes) run `Configure` as shown in the following
267 The options `--prefix` and `--openssldir` are explained in further detail in
268 [Directories](#directories) below, and the values used here are mere examples.
272 $ ./Configure --prefix=/opt/openssl --openssldir=/usr/local/ssl
276 $ perl Configure --prefix=PROGRAM:[INSTALLS] --openssldir=SYS$MANAGER:[OPENSSL]
278 Note: if you do add options to the configuration command, please make sure
279 you've read more than just this Quick Start, such as relevant `NOTES-*` files,
280 the options outline below, as configuration options may change the outcome
281 in otherwise unexpected ways.
283 Configuration Options
284 =====================
286 There are several options to `./Configure` to customize the build (note that
287 for Windows, the defaults for `--prefix` and `--openssldir` depend on what
288 configuration is used and what Windows implementation OpenSSL is built on.
289 For more information, see the [Notes for Windows platforms](NOTES-WINDOWS.md).
296 Build the OpenSSL libraries to support the API for the specified version.
297 If [no-deprecated](#no-deprecated) is also given, don't build with support
298 for deprecated APIs in or below the specified version number. For example,
301 --api=1.1.0 no-deprecated
303 will remove support for all APIs that were deprecated in OpenSSL version
304 1.1.0 or below. This is a rather specialized option for developers.
305 If you just intend to remove all deprecated APIs up to the current version
306 entirely, just specify [no-deprecated](#no-deprecated).
307 If `--api` isn't given, it defaults to the current (minor) OpenSSL version.
312 --cross-compile-prefix=<PREFIX>
314 The `<PREFIX>` to include in front of commands for your toolchain.
316 It is likely to have to end with dash, e.g. `a-b-c-` would invoke GNU compiler
317 as `a-b-c-gcc`, etc. Unfortunately cross-compiling is too case-specific to put
318 together one-size-fits-all instructions. You might have to pass more flags or
319 set up environment variables to actually make it work. Android and iOS cases
320 are discussed in corresponding `Configurations/15-*.conf` files. But there are
321 cases when this option alone is sufficient. For example to build the mingw64
322 target on Linux `--cross-compile-prefix=x86_64-w64-mingw32-` works. Naturally
323 provided that mingw packages are installed. Today Debian and Ubuntu users
324 have option to install a number of prepackaged cross-compilers along with
325 corresponding run-time and development packages for "alien" hardware. To give
326 another example `--cross-compile-prefix=mipsel-linux-gnu-` suffices in such
329 For cross compilation, you must [configure manually](#manual-configuration).
330 Also, note that `--openssldir` refers to target's file system, not one you are
338 Build OpenSSL with debugging symbols and zero optimization level.
342 Build OpenSSL without debugging symbols. This is the default.
351 The name of the directory under the top of the installation directory tree
352 (see the `--prefix` option) where libraries will be installed. By default
353 this is `lib`. Note that on Windows only static libraries (`*.lib`) will
354 be stored in this location. Shared libraries (`*.dll`) will always be
355 installed to the `bin` directory.
357 Some build targets have a multilib postfix set in the build configuration.
358 For these targets the default libdir is `lib<multilib-postfix>`. Please use
359 `--libdir=lib` to override the libdir if adding the postfix is undesirable.
365 Directory for OpenSSL configuration files, and also the default certificate
366 and key store. Defaults are:
369 Windows: C:\Program Files\Common Files\SSL
370 OpenVMS: SYS$COMMON:[OPENSSL-COMMON]
372 For 32bit Windows applications on Windows 64bit (WOW64), always replace
373 `C:\Program Files` by `C:\Program Files (x86)`.
379 The top of the installation directory tree. Defaults are:
382 Windows: C:\Program Files\OpenSSL
383 OpenVMS: SYS$COMMON:[OPENSSL]
390 This is a developer flag that switches on various compiler options recommended
391 for OpenSSL development. It only works when using gcc or clang as the compiler.
392 If you are developing a patch for OpenSSL then it is recommended that you use
393 this option where possible.
398 ### with-zlib-include
400 --with-zlib-include=DIR
402 The directory for the location of the zlib include file. This option is only
403 necessary if [zlib](#zlib) is used and the include file is not
404 already on the system include path.
410 **On Unix**: this is the directory containing the zlib library.
411 If not provided the system library path will be used.
413 **On Windows:** this is the filename of the zlib library (with or
414 without a path). This flag must be provided if the
415 [zlib-dynamic](#zlib-dynamic) option is not also used. If `zlib-dynamic` is used
416 then this flag is optional and defaults to `ZLIB1` if not provided.
418 **On VMS:** this is the filename of the zlib library (with or without a path).
419 This flag is optional and if not provided then `GNV$LIBZSHR`, `GNV$LIBZSHR32`
420 or `GNV$LIBZSHR64` is used by default depending on the pointer size chosen.
422 Seeding the Random Generator
423 ----------------------------
425 --with-rand-seed=seed1[,seed2,...]
427 A comma separated list of seeding methods which will be tried by OpenSSL
428 in order to obtain random input (a.k.a "entropy") for seeding its
429 cryptographically secure random number generator (CSPRNG).
430 The current seeding methods are:
434 Use a trusted operating system entropy source.
435 This is the default method if such an entropy source exists.
439 Use the [getrandom(2)][man-getrandom] or equivalent system call.
441 [man-getrandom]: http://man7.org/linux/man-pages/man2/getrandom.2.html
445 Use the first device from the `DEVRANDOM` list which can be opened to read
446 random bytes. The `DEVRANDOM` preprocessor constant expands to
448 "/dev/urandom","/dev/random","/dev/srandom"
450 on most unix-ish operating systems.
454 Check for an entropy generating daemon.
455 This source is ignored by the FIPS provider.
459 Use the `RDSEED` or `RDRAND` command on x86 or `RNDRRS` command on aarch64
460 if provided by the CPU.
464 Use librandom (not implemented yet).
465 This source is ignored by the FIPS provider.
469 Disable automatic seeding. This is the default on some operating systems where
470 no suitable entropy source exists, or no support for it is implemented yet.
471 This option is ignored by the FIPS provider.
473 For more information, see the section [Notes on random number generation][rng]
474 at the end of this document.
476 [rng]: #notes-on-random-number-generation
478 Setting the FIPS HMAC key
479 -------------------------
483 As part of its self-test validation, the FIPS module must verify itself
484 by performing a SHA-256 HMAC computation on itself. The default key is
485 the SHA256 value of "the holy handgrenade of antioch" and is sufficient
486 for meeting the FIPS requirements.
488 To change the key to a different value, use this flag. The value should
489 be a hex string no more than 64 characters.
491 Enable and Disable Features
492 ---------------------------
494 Feature options always come in pairs, an option to enable feature
495 `xxxx`, and an option to disable it:
497 [ enable-xxxx | no-xxxx ]
499 Whether a feature is enabled or disabled by default, depends on the feature.
500 In the following list, always the non-default variant is documented: if
501 feature `xxxx` is disabled by default then `enable-xxxx` is documented and
502 if feature `xxxx` is enabled by default then `no-xxxx` is documented.
506 Don't build the AFALG engine.
508 This option will be forced on a platform that does not support AFALG.
512 Build with Kernel TLS support.
514 This option will enable the use of the Kernel TLS data-path, which can improve
515 performance and allow for the use of sendfile and splice system calls on
516 TLS sockets. The Kernel may use TLS accelerators if any are available on the
517 system. This option will be forced off on systems that do not support the
518 Kernel TLS data-path.
522 Build with the Address sanitiser.
524 This is a developer option only. It may not work on all platforms and should
525 never be used in production environments. It will only work when used with
526 gcc or clang and should be used in conjunction with the [no-shared](#no-shared)
529 ### enable-acvp-tests
531 Build support for Automated Cryptographic Validation Protocol (ACVP)
534 This is required for FIPS validation purposes. Certain ACVP tests require
535 access to algorithm internals that are not normally accessible.
536 Additional information related to ACVP can be found at
537 <https://github.com/usnistgov/ACVP>.
541 Do not use assembler code.
543 This should be viewed as debugging/troubleshooting option rather than for
544 production use. On some platforms a small amount of assembler code may still
545 be used even with this option.
549 Do not build support for async operations.
553 Don't automatically load all supported ciphers and digests.
555 Typically OpenSSL will make available all of its supported ciphers and digests.
556 For a statically linked application this may be undesirable if small executable
557 size is an objective. This only affects libcrypto. Ciphers and digests will
558 have to be loaded manually using `EVP_add_cipher()` and `EVP_add_digest()`
559 if this option is used. This option will force a non-shared build.
563 Don't automatically load all libcrypto/libssl error strings.
565 Typically OpenSSL will automatically load human readable error strings. For a
566 statically linked application this may be undesirable if small executable size
569 ### no-autoload-config
571 Don't automatically load the default `openssl.cnf` file.
573 Typically OpenSSL will automatically load a system config file which configures
576 ### enable-buildtest-c++
578 While testing, generate C++ buildtest files that simply check that the public
579 OpenSSL header files are usable standalone with C++.
581 Enabling this option demands extra care. For any compiler flag given directly
582 as configuration option, you must ensure that it's valid for both the C and
583 the C++ compiler. If not, the C++ build test will most likely break. As an
584 alternative, you can use the language specific variables, `CFLAGS` and `CXXFLAGS`.
588 Use the specified text instead of the default banner at the end of
593 On platforms where the choice of 32-bit or 64-bit architecture
594 is not explicitly specified, `Configure` will print a warning
595 message and wait for a few seconds to let you interrupt the
596 configuration. Using this flag skips the wait.
600 Build only some minimal set of features.
601 This is a developer option used internally for CI build tests of the project.
605 Never cache algorithms when they are fetched from a provider. Normally, a
606 provider indicates if the algorithms it supplies can be cached or not. Using
607 this option will reduce run-time memory usage but it also introduces a
608 significant performance penalty. This option is primarily designed to help
609 with detecting incorrect reference counting.
613 Don't build the CAPI engine.
615 This option will be forced if on a platform that does not support CAPI.
619 Don't build support for Certificate Management Protocol (CMP)
620 and Certificate Request Message Format (CRMF).
624 Don't build support for Cryptographic Message Syntax (CMS).
628 Don't build support for SSL/TLS compression.
630 If this option is enabled (the default), then compression will only work if
631 the zlib or `zlib-dynamic` options are also chosen.
633 ### enable-crypto-mdebug
635 This now only enables the `failed-malloc` feature.
637 ### enable-crypto-mdebug-backtrace
639 This is a no-op; the project uses the compiler's address/leak sanitizer instead.
643 Don't build support for Certificate Transparency (CT).
647 Don't build with support for deprecated APIs up until and including the version
648 given with `--api` (or the current version, if `--api` wasn't specified).
652 Don't build support for datagram based BIOs.
654 Selecting this option will also force the disabling of DTLS.
658 Don't build support for loading Dynamic Shared Objects (DSO)
660 ### enable-devcryptoeng
662 Build the `/dev/crypto` engine.
664 This option is automatically selected on the BSD platform, in which case it can
665 be disabled with `no-devcryptoeng`.
667 ### no-dynamic-engine
669 Don't build the dynamically loaded engines.
671 This only has an effect in a shared build.
675 Don't build support for Elliptic Curves.
679 Don't build support for binary Elliptic Curves
681 ### enable-ec_nistp_64_gcc_128
683 Enable support for optimised implementations of some commonly used NIST
686 This option is only supported on platforms:
688 - with little-endian storage of non-byte types
689 - that tolerate misaligned memory references
690 - where the compiler:
691 - supports the non-standard type `__uint128_t`
692 - defines the built-in macro `__SIZEOF_INT128__`
696 Build support for gathering entropy from the Entropy Gathering Daemon (EGD).
700 Don't build support for loading engines.
704 Don't compile in any error strings.
706 ### enable-external-tests
708 Enable building of integration with external test suites.
710 This is a developer option and may not work on all platforms. The following
711 external test suites are currently supported:
713 - GOST engine test suite
714 - Python PYCA/Cryptography test suite
717 See the file [test/README-external.md](test/README-external.md)
722 Don't compile in filename and line number information (e.g. for errors and
727 Build (and install) the FIPS provider
729 ### no-fips-securitychecks
731 Don't perform FIPS module run-time checks related to enforcement of security
732 parameters such as minimum security strength of keys.
734 ### enable-fuzz-libfuzzer, enable-fuzz-afl
736 Build with support for fuzzing using either libfuzzer or AFL.
738 These are developer options only. They may not work on all platforms and
739 should never be used in production environments.
741 See the file [fuzz/README.md](fuzz/README.md) for further details.
745 Don't build support for GOST based ciphersuites.
747 Note that if this feature is enabled then GOST ciphersuites are only available
748 if the GOST algorithms are also available through loading an externally supplied
753 Don't build the legacy provider.
755 Disabling this also disables the legacy algorithms: MD2 (already disabled by default).
759 Don't generate dependencies.
763 Don't build any dynamically loadable engines.
765 This also implies `no-dynamic-engine`.
769 Don't build support for writing multiple records in one go in libssl
771 Note: this is a different capability to the pipelining functionality.
775 Don't build support for the Next Protocol Negotiation (NPN) TLS extension.
779 Don't build support for Online Certificate Status Protocol (OCSP).
783 Don't build the padlock engine.
787 As synonym for `no-padlockeng`. Deprecated and should not be used.
791 Don't build with support for Position Independent Code.
795 Don't pin the shared libraries.
797 By default OpenSSL will attempt to stay in memory until the process exits.
798 This is so that libcrypto and libssl can be properly cleaned up automatically
799 via an `atexit()` handler. The handler is registered by libcrypto and cleans
800 up both libraries. On some platforms the `atexit()` handler will run on unload of
801 libcrypto (if it has been dynamically loaded) rather than at process exit. This
802 option can be used to stop OpenSSL from attempting to stay in memory until the
803 process exits. This could lead to crashes if either libcrypto or libssl have
804 already been unloaded at the point that the atexit handler is invoked, e.g. on a
805 platform which calls `atexit()` on unload of the library, and libssl is unloaded
806 before libcrypto then a crash is likely to happen. Applications can suppress
807 running of the `atexit()` handler at run time by using the
808 `OPENSSL_INIT_NO_ATEXIT` option to `OPENSSL_init_crypto()`.
809 See the man page for it for further details.
813 Don't use POSIX IO capabilities.
817 Don't build support for Pre-Shared Key based ciphersuites.
821 Don't use hardware RDRAND capabilities.
825 Don't build support for RFC3779, "X.509 Extensions for IP Addresses and
830 Build support for Stream Control Transmission Protocol (SCTP).
834 Do not create shared libraries, only static ones.
836 See [Notes on shared libraries](#notes-on-shared-libraries) below.
840 Don't build support for socket BIOs.
844 Don't build support for Secure Remote Password (SRP) protocol or
845 SRP based ciphersuites.
849 Don't build Secure Real-Time Transport Protocol (SRTP) support.
853 Exclude SSE2 code paths from 32-bit x86 assembly modules.
855 Normally SSE2 extension is detected at run-time, but the decision whether or not
856 the machine code will be executed is taken solely on CPU capability vector. This
857 means that if you happen to run OS kernel which does not support SSE2 extension
858 on Intel P4 processor, then your application might be exposed to "illegal
859 instruction" exception. There might be a way to enable support in kernel, e.g.
860 FreeBSD kernel can be compiled with `CPU_ENABLE_SSE`, and there is a way to
861 disengage SSE2 code paths upon application start-up, but if you aim for wider
862 "audience" running such kernel, consider `no-sse2`. Both the `386` and `no-asm`
863 options imply `no-sse2`.
867 Don't build with SSL Trace capabilities.
869 This removes the `-trace` option from `s_client` and `s_server`, and omits the
870 `SSL_trace()` function from libssl.
872 Disabling `ssl-trace` may provide a small reduction in libssl binary size.
876 Don't build the statically linked engines.
878 This only has an impact when not built "shared".
882 Don't use anything from the C header file `stdio.h` that makes use of the `FILE`
883 type. Only libcrypto and libssl can be built in this way. Using this option will
884 suppress building the command line applications. Additionally, since the OpenSSL
885 tests also use the command line applications, the tests will also be skipped.
889 Don't build test programs or run any tests.
893 Don't build with support for multi-threaded applications.
897 Build with support for multi-threaded applications. Most platforms will enable
898 this by default. However, if on a platform where this is not the case then this
899 will usually require additional system-dependent options!
901 See [Notes on multi-threading](#notes-on-multi-threading) below.
905 Build with support for the integrated tracing api.
907 See manual pages OSSL_trace_set_channel(3) and OSSL_trace_enabled(3) for details.
911 Don't build Time Stamping (TS) Authority support.
915 Build with the Undefined Behaviour sanitiser (UBSAN).
917 This is a developer option only. It may not work on all platforms and should
918 never be used in production environments. It will only work when used with
919 gcc or clang and should be used in conjunction with the `-DPEDANTIC` option
920 (or the `--strict-warnings` option).
924 Don't build with the User Interface (UI) console method
926 The User Interface console method enables text based console prompts.
930 Enable additional unit test APIs.
932 This should not typically be used in production deployments.
936 Don't build support for UPLINK interface.
938 ### enable-weak-ssl-ciphers
940 Build support for SSL/TLS ciphers that are considered "weak"
942 Enabling this includes for example the RC4 based ciphersuites.
946 Build with support for zlib compression/decompression.
950 Like the zlib option, but has OpenSSL load the zlib library dynamically
953 This is only supported on systems where loading of shared libraries is supported.
957 In 32-bit x86 builds, use the 80386 instruction set only in assembly modules
959 The default x86 code is more efficient, but requires at least an 486 processor.
960 Note: This doesn't affect compiler generated code, so this option needs to be
961 accompanied by a corresponding compiler-specific option.
965 no-{ssl|ssl3|tls|tls1|tls1_1|tls1_2|tls1_3|dtls|dtls1|dtls1_2}
967 Don't build support for negotiating the specified SSL/TLS protocol.
969 If `no-tls` is selected then all of `tls1`, `tls1_1`, `tls1_2` and `tls1_3`
971 Similarly `no-dtls` will disable `dtls1` and `dtls1_2`. The `no-ssl` option is
972 synonymous with `no-ssl3`. Note this only affects version negotiation.
973 OpenSSL will still provide the methods for applications to explicitly select
974 the individual protocol versions.
976 ### no-{protocol}-method
978 no-{ssl3|tls1|tls1_1|tls1_2|dtls1|dtls1_2}-method
980 Analogous to `no-{protocol}` but in addition do not build the methods for
981 applications to explicitly select individual protocol versions. Note that there
982 is no `no-tls1_3-method` option because there is no application method for
985 Using individual protocol methods directly is deprecated. Applications should
986 use `TLS_method()` instead.
988 ### enable-{algorithm}
992 Build with support for the specified algorithm.
996 no-{aria|bf|blake2|camellia|cast|chacha|cmac|
997 des|dh|dsa|ecdh|ecdsa|idea|md4|mdc2|ocb|
998 poly1305|rc2|rc4|rmd160|scrypt|seed|
999 siphash|siv|sm2|sm3|sm4|whirlpool}
1001 Build without support for the specified algorithm.
1003 The `ripemd` algorithm is deprecated and if used is synonymous with `rmd160`.
1005 ### Compiler-specific options
1007 -Dxxx, -Ixxx, -Wp, -lxxx, -Lxxx, -Wl, -rpath, -R, -framework, -static
1009 These system specific options will be recognised and passed through to the
1010 compiler to allow you to define preprocessor symbols, specify additional
1011 libraries, library directories or other compiler options. It might be worth
1012 noting that some compilers generate code specifically for processor the
1013 compiler currently executes on. This is not necessarily what you might have
1014 in mind, since it might be unsuitable for execution on other, typically older,
1015 processor. Consult your compiler documentation.
1017 Take note of the [Environment Variables](#environment-variables) documentation
1018 below and how these flags interact with those variables.
1022 Additional options that are not otherwise recognised are passed through as
1023 they are to the compiler as well. Unix-style options beginning with a
1024 `-` or `+` and Windows-style options beginning with a `/` are recognised.
1025 Again, consult your compiler documentation.
1027 If the option contains arguments separated by spaces, then the URL-style
1028 notation `%20` can be used for the space character in order to avoid having
1029 to quote the option. For example, `-opt%20arg` gets expanded to `-opt arg`.
1030 In fact, any ASCII character can be encoded as %xx using its hexadecimal
1033 Take note of the [Environment Variables](#environment-variables) documentation
1034 below and how these flags interact with those variables.
1036 ### Environment Variables
1040 Assign the given value to the environment variable `VAR` for `Configure`.
1042 These work just like normal environment variable assignments, but are supported
1043 on all platforms and are confined to the configuration scripts only.
1044 These assignments override the corresponding value in the inherited environment,
1047 The following variables are used as "`make` variables" and can be used as an
1048 alternative to giving preprocessor, compiler and linker options directly as
1049 configuration. The following variables are supported:
1051 AR The static library archiver.
1052 ARFLAGS Flags for the static library archiver.
1053 AS The assembler compiler.
1054 ASFLAGS Flags for the assembler compiler.
1056 CFLAGS Flags for the C compiler.
1057 CXX The C++ compiler.
1058 CXXFLAGS Flags for the C++ compiler.
1059 CPP The C/C++ preprocessor.
1060 CPPFLAGS Flags for the C/C++ preprocessor.
1061 CPPDEFINES List of CPP macro definitions, separated
1062 by a platform specific character (':' or
1063 space for Unix, ';' for Windows, ',' for
1064 VMS). This can be used instead of using
1065 -D (or what corresponds to that on your
1066 compiler) in CPPFLAGS.
1067 CPPINCLUDES List of CPP inclusion directories, separated
1068 the same way as for CPPDEFINES. This can
1069 be used instead of -I (or what corresponds
1070 to that on your compiler) in CPPFLAGS.
1071 HASHBANGPERL Perl invocation to be inserted after '#!'
1072 in public perl scripts (only relevant on
1074 LD The program linker (not used on Unix, $(CC)
1076 LDFLAGS Flags for the shared library, DSO and
1078 LDLIBS Extra libraries to use when linking.
1079 Takes the form of a space separated list
1080 of library specifications on Unix and
1081 Windows, and as a comma separated list of
1083 RANLIB The library archive indexer.
1084 RC The Windows resource compiler.
1085 RCFLAGS Flags for the Windows resource compiler.
1086 RM The command to remove files and directories.
1088 These cannot be mixed with compiling/linking flags given on the command line.
1089 In other words, something like this isn't permitted.
1091 $ ./Configure -DFOO CPPFLAGS=-DBAR -DCOOKIE
1093 Backward compatibility note:
1095 To be compatible with older configuration scripts, the environment variables
1096 are ignored if compiling/linking flags are given on the command line, except
1099 AR, CC, CXX, CROSS_COMPILE, HASHBANGPERL, PERL, RANLIB, RC, and WINDRES
1101 For example, the following command will not see `-DBAR`:
1103 $ CPPFLAGS=-DBAR ./Configure -DCOOKIE
1105 However, the following will see both set variables:
1107 $ CC=gcc CROSS_COMPILE=x86_64-w64-mingw32- ./Configure -DCOOKIE
1109 If `CC` is set, it is advisable to also set `CXX` to ensure both the C and C++
1110 compiler are in the same "family". This becomes relevant with
1111 `enable-external-tests` and `enable-buildtest-c++`.
1118 Reconfigure from earlier data.
1120 This fetches the previous command line options and environment from data
1121 saved in `configdata.pm` and runs the configuration process again, using
1122 these options and environment. Note: NO other option is permitted together
1123 with `reconf`. Note: The original configuration saves away values for ALL
1124 environment variables that were used, and if they weren't defined, they are
1125 still saved away with information that they weren't originally defined.
1126 This information takes precedence over environment variables that are
1127 defined when reconfiguring.
1129 Displaying configuration data
1130 -----------------------------
1132 The configuration script itself will say very little, and finishes by
1133 creating `configdata.pm`. This perl module can be loaded by other scripts
1134 to find all the configuration data, and it can also be used as a script to
1135 display all sorts of configuration data in a human readable form.
1137 For more information, please do:
1139 $ ./configdata.pm --help # Unix
1143 $ perl configdata.pm --help # Windows and VMS
1145 Installation Steps in Detail
1146 ============================
1151 ### Automatic Configuration
1153 In previous version, the `config` script determined the platform type and
1154 compiler and then called `Configure`. Starting with this release, they are
1157 #### Unix / Linux / macOS
1159 $ ./Configure [[ options ]]
1163 $ perl Configure [[ options ]]
1167 $ perl Configure [[ options ]]
1169 ### Manual Configuration
1171 OpenSSL knows about a range of different operating system, hardware and
1172 compiler combinations. To see the ones it knows about, run
1174 $ ./Configure LIST # Unix
1178 $ perl Configure LIST # All other platforms
1180 For the remainder of this text, the Unix form will be used in all examples.
1181 Please use the appropriate form for your platform.
1183 Pick a suitable name from the list that matches your system. For most
1184 operating systems there is a choice between using cc or gcc.
1185 When you have identified your system (and if necessary compiler) use this
1186 name as the argument to `Configure`. For example, a `linux-elf` user would
1189 $ ./Configure linux-elf [[ options ]]
1191 ### Creating your own Configuration
1193 If your system isn't listed, you will have to create a configuration
1194 file named `Configurations/{{ something }}.conf` and add the correct
1195 configuration for your system. See the available configs as examples
1196 and read [Configurations/README.md](Configurations/README.md) and
1197 [Configurations/README-design.md](Configurations/README-design.md)
1198 for more information.
1200 The generic configurations `cc` or `gcc` should usually work on 32 bit
1203 `Configure` creates a build file (`Makefile` on Unix, `makefile` on Windows
1204 and `descrip.mms` on OpenVMS) from a suitable template in `Configurations/`,
1205 and defines various macros in `include/openssl/configuration.h` (generated
1206 from `include/openssl/configuration.h.in`.
1208 ### Out of Tree Builds
1210 OpenSSL can be configured to build in a build directory separate from the
1211 source code directory. It's done by placing yourself in some other
1212 directory and invoking the configuration commands from there.
1216 $ mkdir /var/tmp/openssl-build
1217 $ cd /var/tmp/openssl-build
1218 $ /PATH/TO/OPENSSL/SOURCE/Configure [[ options ]]
1220 #### OpenVMS example
1222 $ set default sys$login:
1223 $ create/dir [.tmp.openssl-build]
1224 $ set default [.tmp.openssl-build]
1225 $ perl D:[PATH.TO.OPENSSL.SOURCE]Configure [[ options ]]
1227 #### Windows example
1230 $ mkdir \temp-openssl
1232 $ perl d:\PATH\TO\OPENSSL\SOURCE\Configure [[ options ]]
1234 Paths can be relative just as well as absolute. `Configure` will do its best
1235 to translate them to relative paths whenever possible.
1240 Build OpenSSL by running:
1243 $ mms ! (or mmk) OpenVMS
1246 This will build the OpenSSL libraries (`libcrypto.a` and `libssl.a` on
1247 Unix, corresponding on other platforms) and the OpenSSL binary
1248 (`openssl`). The libraries will be built in the top-level directory,
1249 and the binary will be in the `apps/` subdirectory.
1251 If the build fails, take a look at the [Build Failures](#build-failures)
1252 subsection of the [Troubleshooting](#troubleshooting) section.
1257 After a successful build, and before installing, the libraries should
1261 $ mms test ! OpenVMS
1262 $ nmake test # Windows
1264 **Warning:** you MUST run the tests from an unprivileged account (or disable
1265 your privileges temporarily if your platform allows it).
1267 See [test/README.md](test/README.md) for further details how run tests.
1269 See [test/README-dev.md](test/README-dev.md) for guidelines on adding tests.
1274 If everything tests ok, install OpenSSL with
1276 $ make install # Unix
1277 $ mms install ! OpenVMS
1278 $ nmake install # Windows
1280 Note that in order to perform the install step above you need to have
1281 appropriate permissions to write to the installation directory.
1283 The above commands will install all the software components in this
1284 directory tree under `<PREFIX>` (the directory given with `--prefix` or
1287 ### Unix / Linux / macOS
1289 bin/ Contains the openssl binary and a few other
1292 Contains the header files needed if you want
1293 to build your own programs that use libcrypto
1295 lib Contains the OpenSSL library files.
1296 lib/engines Contains the OpenSSL dynamically loadable engines.
1298 share/man/man1 Contains the OpenSSL command line man-pages.
1299 share/man/man3 Contains the OpenSSL library calls man-pages.
1300 share/man/man5 Contains the OpenSSL configuration format man-pages.
1301 share/man/man7 Contains the OpenSSL other misc man-pages.
1303 share/doc/openssl/html/man1
1304 share/doc/openssl/html/man3
1305 share/doc/openssl/html/man5
1306 share/doc/openssl/html/man7
1307 Contains the HTML rendition of the man-pages.
1311 'arch' is replaced with the architecture name, `ALPHA` or `IA64`,
1312 'sover' is replaced with the shared library version (`0101` for 1.1), and
1313 'pz' is replaced with the pointer size OpenSSL was built with:
1315 [.EXE.'arch'] Contains the openssl binary.
1316 [.EXE] Contains a few utility scripts.
1318 Contains the header files needed if you want
1319 to build your own programs that use libcrypto
1321 [.LIB.'arch'] Contains the OpenSSL library files.
1322 [.ENGINES'sover''pz'.'arch']
1323 Contains the OpenSSL dynamically loadable engines.
1324 [.SYS$STARTUP] Contains startup, login and shutdown scripts.
1325 These define appropriate logical names and
1327 [.SYSTEST] Contains the installation verification procedure.
1328 [.HTML] Contains the HTML rendition of the manual pages.
1330 ### Additional Directories
1332 Additionally, install will add the following directories under
1333 OPENSSLDIR (the directory given with `--openssldir` or its default)
1334 for you convenience:
1336 certs Initially empty, this is the default location
1337 for certificate files.
1338 private Initially empty, this is the default location
1339 for private key files.
1340 misc Various scripts.
1342 The installation directory should be appropriately protected to ensure
1343 unprivileged users cannot make changes to OpenSSL binaries or files, or
1344 install engines. If you already have a pre-installed version of OpenSSL as
1345 part of your Operating System it is recommended that you do not overwrite
1346 the system version and instead install to somewhere else.
1348 Package builders who want to configure the library for standard locations,
1349 but have the package installed somewhere else so that it can easily be
1352 $ make DESTDIR=/tmp/package-root install # Unix
1353 $ mms/macro="DESTDIR=TMP:[PACKAGE-ROOT]" install ! OpenVMS
1355 The specified destination directory will be prepended to all installation
1358 Compatibility issues with previous OpenSSL versions
1359 ---------------------------------------------------
1361 ### COMPILING existing applications
1363 Starting with version 1.1.0, OpenSSL hides a number of structures that were
1364 previously open. This includes all internal libssl structures and a number
1365 of EVP types. Accessor functions have been added to allow controlled access
1366 to the structures' data.
1368 This means that some software needs to be rewritten to adapt to the new ways
1369 of doing things. This often amounts to allocating an instance of a structure
1370 explicitly where you could previously allocate them on the stack as automatic
1371 variables, and using the provided accessor functions where you would previously
1372 access a structure's field directly.
1374 Some APIs have changed as well. However, older APIs have been preserved when
1377 Post-installation Notes
1378 -----------------------
1380 With the default OpenSSL installation comes a FIPS provider module, which
1381 needs some post-installation attention, without which it will not be usable.
1382 This involves using the following command:
1384 $ openssl fipsinstall
1386 See the openssl-fipsinstall(1) manual for details and examples.
1388 Advanced Build Options
1389 ======================
1391 Environment Variables
1392 ---------------------
1394 A number of environment variables can be used to provide additional control
1395 over the build process. Typically these should be defined prior to running
1396 `Configure`. Not all environment variables are relevant to all platforms.
1399 The name of the ar executable to use.
1402 Use a different build file name than the platform default
1403 ("Makefile" on Unix-like platforms, "makefile" on native Windows,
1404 "descrip.mms" on OpenVMS). This requires that there is a
1405 corresponding build file template.
1406 See [Configurations/README.md](Configurations/README.md)
1407 for further information.
1410 The compiler to use. Configure will attempt to pick a default
1411 compiler for your platform but this choice can be overridden
1412 using this variable. Set it to the compiler executable you wish
1413 to use, e.g. gcc or clang.
1416 This environment variable has the same meaning as for the
1417 "--cross-compile-prefix" Configure flag described above. If both
1418 are set then the Configure flag takes precedence.
1421 The command string for the Perl executable to insert in the
1422 #! line of perl scripts that will be publicly installed.
1423 Default: /usr/bin/env perl
1424 Note: the value of this variable is added to the same scripts
1425 on all platforms, but it's only relevant on Unix-like platforms.
1428 This can be the value `32` or `64` to specify the architecture
1429 when it is not "obvious" to the configuration. It should generally
1430 not be necessary to specify this environment variable.
1433 The name of the nm executable to use.
1435 OPENSSL_LOCAL_CONFIG_DIR
1436 OpenSSL comes with a database of information about how it
1437 should be built on different platforms as well as build file
1438 templates for those platforms. The database is comprised of
1439 ".conf" files in the Configurations directory. The build
1440 file templates reside there as well as ".tmpl" files. See the
1441 file [Configurations/README.md](Configurations/README.md)
1442 for further information about the format of ".conf" files
1443 as well as information on the ".tmpl" files.
1444 In addition to the standard ".conf" and ".tmpl" files, it is
1445 possible to create your own ".conf" and ".tmpl" files and
1446 store them locally, outside the OpenSSL source tree.
1447 This environment variable can be set to the directory where
1448 these files are held and will be considered by Configure
1449 before it looks in the standard directories.
1452 The name of the Perl executable to use when building OpenSSL.
1453 Only needed if builing should use a different Perl executable
1454 than what is used to run the Configure script.
1457 The name of the ranlib executable to use.
1460 The name of the rc executable to use. The default will be as
1461 defined for the target platform in the ".conf" file. If not
1462 defined then "windres" will be used. The WINDRES environment
1463 variable is synonymous to this. If both are defined then RC
1472 The `Configure` script generates a Makefile in a format relevant to the specific
1473 platform. The Makefiles provide a number of targets that can be used. Not all
1474 targets may be available on all platforms. Only the most common targets are
1475 described here. Examine the Makefiles themselves for the full list.
1478 The target to build all the software components and
1482 Build all the software components.
1483 THIS IS THE DEFAULT TARGET.
1486 Build all documentation components.
1489 Remove all build artefacts and return the directory to a "clean"
1493 Rebuild the dependencies in the Makefiles. This is a legacy
1494 option that no longer needs to be used since OpenSSL 1.1.0.
1497 Install all OpenSSL components.
1500 Only install the OpenSSL software components.
1503 Only install the OpenSSL documentation components.
1506 Only install the OpenSSL man pages (Unix only).
1509 Only install the OpenSSL HTML documentation.
1512 Install the FIPS provider module configuration file.
1515 Prints a list of all the self test names.
1518 Build and run the OpenSSL self tests.
1521 Uninstall all OpenSSL components.
1525 Re-run the configuration process, as exactly as the last time
1529 This is a developer option. If you are developing a patch for
1530 OpenSSL you may need to use this if you want to update
1531 automatically generated files; add new error codes or add new
1532 (or change the visibility of) public API functions. (Unix only).
1534 Running Selected Tests
1535 ----------------------
1537 You can specify a set of tests to be performed
1538 using the `make` variable `TESTS`.
1540 See the section [Running Selected Tests of
1541 test/README.md](test/README.md#running-selected-tests).
1546 Configuration Problems
1547 ----------------------
1549 ### Selecting the correct target
1551 The `./Configure` script tries hard to guess your operating system, but in some
1552 cases it does not succeed. You will see a message like the following:
1555 Operating system: x86-whatever-minix
1556 This system (minix) is not supported. See file INSTALL.md for details.
1558 Even if the automatic target selection by the `./Configure` script fails,
1559 chances are that you still might find a suitable target in the `Configurations`
1560 directory, which you can supply to the `./Configure` command,
1561 possibly after some adjustment.
1563 The `Configurations/` directory contains a lot of examples of such targets.
1564 The main configuration file is [10-main.conf], which contains all targets that
1565 are officially supported by the OpenSSL team. Other configuration files contain
1566 targets contributed by other OpenSSL users. The list of targets can be found in
1567 a Perl list `my %targets = ( ... )`.
1572 inherit_from => [ "base-target" ],
1574 cflags => add("..."),
1576 perlasm_scheme => "...",
1581 If you call `./Configure` without arguments, it will give you a list of all
1582 known targets. Using `grep`, you can lookup the target definition in the
1583 `Configurations/` directory. For example the `android-x86_64` can be found in
1584 [Configurations/15-android.conf](Configurations/15-android.conf).
1586 The directory contains two README files, which explain the general syntax and
1587 design of the configuration files.
1589 - [Configurations/README.md](Configurations/README.md)
1590 - [Configurations/README-design.md](Configurations/README-design.md)
1592 If you need further help, try to search the [openssl-users] mailing list
1593 or the [GitHub Issues] for existing solutions. If you don't find anything,
1594 you can [raise an issue] to ask a question yourself.
1596 More about our support resources can be found in the [SUPPORT] file.
1598 ### Configuration Errors
1600 If the `./Configure` or `./Configure` command fails with an error message,
1601 read the error message carefully and try to figure out whether you made
1602 a mistake (e.g., by providing a wrong option), or whether the script is
1603 working incorrectly. If you think you encountered a bug, please
1604 [raise an issue] on GitHub to file a bug report.
1606 Along with a short description of the bug, please provide the complete
1607 configure command line and the relevant output including the error message.
1609 Note: To make the output readable, please add a 'code fence' (three backquotes
1610 ` ``` ` on a separate line) before and after your output:
1613 ./Configure [your arguments...]
1622 If the build fails, look carefully at the output. Try to locate and understand
1623 the error message. It might be that the compiler is already telling you
1624 exactly what you need to do to fix your problem.
1626 There may be reasons for the failure that aren't problems in OpenSSL itself,
1627 for example if the compiler reports missing standard or third party headers.
1629 If the build succeeded previously, but fails after a source or configuration
1630 change, it might be helpful to clean the build tree before attempting another
1631 build. Use this command:
1634 $ mms clean ! (or mmk) OpenVMS
1635 $ nmake clean # Windows
1637 Assembler error messages can sometimes be sidestepped by using the `no-asm`
1638 configuration option. See also [notes](#notes-on-assembler-modules-compilation).
1640 Compiling parts of OpenSSL with gcc and others with the system compiler will
1641 result in unresolved symbols on some systems.
1643 If you are still having problems, try to search the [openssl-users] mailing
1644 list or the [GitHub Issues] for existing solutions. If you think you
1645 encountered an OpenSSL bug, please [raise an issue] to file a bug report.
1646 Please take the time to review the existing issues first; maybe the bug was
1647 already reported or has already been fixed.
1652 If some tests fail, look at the output. There may be reasons for the failure
1653 that isn't a problem in OpenSSL itself (like an OS malfunction or a Perl issue).
1655 You may want increased verbosity, that can be accomplished as described in
1656 section [Test Failures of test/README.md](test/README.md#test-failures).
1658 You may also want to selectively specify which test(s) to perform. This can be
1659 done using the `make` variable `TESTS` as described in section [Running
1660 Selected Tests of test/README.md](test/README.md#running-selected-tests).
1662 If you find a problem with OpenSSL itself, try removing any
1663 compiler optimization flags from the `CFLAGS` line in the Makefile and
1664 run `make clean; make` or corresponding.
1666 To report a bug please open an issue on GitHub, at
1667 <https://github.com/openssl/openssl/issues>.
1672 Notes on multi-threading
1673 ------------------------
1675 For some systems, the OpenSSL `Configure` script knows what compiler options
1676 are needed to generate a library that is suitable for multi-threaded
1677 applications. On these systems, support for multi-threading is enabled
1678 by default; use the `no-threads` option to disable (this should never be
1681 On other systems, to enable support for multi-threading, you will have
1682 to specify at least two options: `threads`, and a system-dependent option.
1683 (The latter is `-D_REENTRANT` on various systems.) The default in this
1684 case, obviously, is not to include support for multi-threading (but
1685 you can still use `no-threads` to suppress an annoying warning message
1686 from the `Configure` script.)
1688 OpenSSL provides built-in support for two threading models: pthreads (found on
1689 most UNIX/Linux systems), and Windows threads. No other threading models are
1690 supported. If your platform does not provide pthreads or Windows threads then
1691 you should use `Configure` with the `no-threads` option.
1693 For pthreads, all locks are non-recursive. In addition, in a debug build,
1694 the mutex attribute `PTHREAD_MUTEX_ERRORCHECK` is used. If this is not
1695 available on your platform, you might have to add
1696 `-DOPENSSL_NO_MUTEX_ERRORCHECK` to your `Configure` invocation.
1697 (On Linux `PTHREAD_MUTEX_ERRORCHECK` is an enum value, so a built-in
1698 ifdef test cannot be used.)
1700 Notes on shared libraries
1701 -------------------------
1703 For most systems the OpenSSL `Configure` script knows what is needed to
1704 build shared libraries for libcrypto and libssl. On these systems
1705 the shared libraries will be created by default. This can be suppressed and
1706 only static libraries created by using the `no-shared` option. On systems
1707 where OpenSSL does not know how to build shared libraries the `no-shared`
1708 option will be forced and only static libraries will be created.
1710 Shared libraries are named a little differently on different platforms.
1711 One way or another, they all have the major OpenSSL version number as
1712 part of the file name, i.e. for OpenSSL 1.1.x, `1.1` is somehow part of
1715 On most POSIX platforms, shared libraries are named `libcrypto.so.1.1`
1716 and `libssl.so.1.1`.
1718 on Cygwin, shared libraries are named `cygcrypto-1.1.dll` and `cygssl-1.1.dll`
1719 with import libraries `libcrypto.dll.a` and `libssl.dll.a`.
1721 On Windows build with MSVC or using MingW, shared libraries are named
1722 `libcrypto-1_1.dll` and `libssl-1_1.dll` for 32-bit Windows,
1723 `libcrypto-1_1-x64.dll` and `libssl-1_1-x64.dll` for 64-bit x86_64 Windows,
1724 and `libcrypto-1_1-ia64.dll` and `libssl-1_1-ia64.dll` for IA64 Windows.
1725 With MSVC, the import libraries are named `libcrypto.lib` and `libssl.lib`,
1726 while with MingW, they are named `libcrypto.dll.a` and `libssl.dll.a`.
1728 On VMS, shareable images (VMS speak for shared libraries) are named
1729 `ossl$libcrypto0101_shr.exe` and `ossl$libssl0101_shr.exe`. However, when
1730 OpenSSL is specifically built for 32-bit pointers, the shareable images
1731 are named `ossl$libcrypto0101_shr32.exe` and `ossl$libssl0101_shr32.exe`
1732 instead, and when built for 64-bit pointers, they are named
1733 `ossl$libcrypto0101_shr64.exe` and `ossl$libssl0101_shr64.exe`.
1735 Notes on random number generation
1736 ---------------------------------
1738 Availability of cryptographically secure random numbers is required for
1739 secret key generation. OpenSSL provides several options to seed the
1740 internal CSPRNG. If not properly seeded, the internal CSPRNG will refuse
1741 to deliver random bytes and a "PRNG not seeded error" will occur.
1743 The seeding method can be configured using the `--with-rand-seed` option,
1744 which can be used to specify a comma separated list of seed methods.
1745 However, in most cases OpenSSL will choose a suitable default method,
1746 so it is not necessary to explicitly provide this option. Note also
1747 that not all methods are available on all platforms. The FIPS provider will
1748 silently ignore seed sources that were not validated.
1750 I) On operating systems which provide a suitable randomness source (in
1751 form of a system call or system device), OpenSSL will use the optimal
1752 available method to seed the CSPRNG from the operating system's
1753 randomness sources. This corresponds to the option `--with-rand-seed=os`.
1755 II) On systems without such a suitable randomness source, automatic seeding
1756 and reseeding is disabled (`--with-rand-seed=none`) and it may be necessary
1757 to install additional support software to obtain a random seed and reseed
1758 the CSPRNG manually. Please check out the manual pages for `RAND_add()`,
1759 `RAND_bytes()`, `RAND_egd()`, and the FAQ for more information.
1761 Notes on assembler modules compilation
1762 --------------------------------------
1764 Compilation of some code paths in assembler modules might depend on whether the
1765 current assembler version supports certain ISA extensions or not. Code paths
1766 that use the AES-NI, PCLMULQDQ, SSSE3, and SHA extensions are always assembled.
1767 Apart from that, the minimum requirements for the assembler versions are shown
1770 | ISA extension | GNU as | nasm | llvm |
1771 |---------------|--------|--------|---------|
1772 | AVX | 2.19 | 2.09 | 3.0 |
1773 | AVX2 | 2.22 | 2.10 | 3.1 |
1774 | ADCX/ADOX | 2.23 | 2.10 | 3.3 |
1775 | AVX512 | 2.25 | 2.11.8 | 3.6 (*) |
1776 | AVX512IFMA | 2.26 | 2.11.8 | 6.0 (*) |
1777 | VAES | 2.30 | 2.13.3 | 6.0 (*) |
1781 (*) Even though AVX512 support was implemented in llvm 3.6, prior to version 7.0
1782 an explicit -march flag was apparently required to compile assembly modules. But
1783 then the compiler generates processor-specific code, which in turn contradicts
1784 the idea of performing dispatch at run-time, which is facilitated by the special
1785 variable `OPENSSL_ia32cap`. For versions older than 7.0, it is possible to work
1786 around the problem by forcing the build procedure to use the following script:
1789 exec clang -no-integrated-as "$@"
1791 instead of the real clang. In which case it doesn't matter what clang version
1792 is used, as it is the version of the GNU assembler that will be checked.
1799 <https://mta.openssl.org/mailman/listinfo/openssl-users>
1805 <https://github.com/openssl/openssl/issues>
1808 <https://github.com/openssl/openssl/issues/new/choose>
1811 Configurations/10-main.conf