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This document describes installation on all supported operating
systems (the Unix/Linux family (which includes Mac OS/X), OpenVMS,
and Windows).
To install OpenSSL, you will need:
* A make implementation
* Perl 5 with core modules (please read NOTES.PERL)
* The perl module Text::Template (please read NOTES.PERL)
* an ANSI C compiler
* a development environment in the form of development libraries and C
header files
* a supported operating system
For additional platform specific requirements, solutions to specific
issues and other details, please read one of these:
* NOTES.UNIX (any supported Unix like system)
* NOTES.WIN (any supported Windows)
* NOTES.DJGPP (DOS platform with DJGPP)
* NOTES.ANDROID (obviously Android [NDK])
* NOTES.VALGRIND (testing with Valgrind)
Notational conventions in this document
Throughout this document, we use the following conventions in command
$ command Any line starting with a dollar sign
($) is a command line.
{ word1 | word2 | word3 } This denotes a mandatory choice, to be
replaced with one of the given words.
A simple example would be this:
$ echo { FOO | BAR | COOKIE }
which is to be understood as one of
$ echo FOO
- or -
$ echo BAR
- or -
$ echo COOKIE
[ word1 | word2 | word3 ] Similar to { word1 | word2 | word3 }
except it's optional to give any of
those. In addition to the examples
above, this would also be valid:
$ echo
{{ target }} This denotes a mandatory word or
sequence of words of some sort. A
simple example would be this:
$ type {{ filename }}
which is to be understood to use the
command 'type' on some file name
determined by the user.
[[ options ]] Similar to {{ target }}, but is
Note that the notation assumes spaces around {, }, [, ], {{, }} and
[[, ]]. This is to differentiate from OpenVMS directory
specifications, which also use [ and ], but without spaces.
Quick Start
If you want to just get on with it, do:
on Unix (again, this includes Mac OS/X):
$ ./config
$ make
$ make test
$ make install
on OpenVMS:
$ @config
$ mms
$ mms test
$ mms install
on Windows (only pick one of the targets for configuration):
$ perl Configure { VC-WIN32 | VC-WIN64A | VC-WIN64I | VC-CE }
$ nmake
$ nmake test
$ nmake install
If any of these steps fails, see section Installation in Detail below.
This will build and install OpenSSL in the default location, which is:
Unix: normal installation directories under /usr/local
OpenVMS: SYS$COMMON:[OPENSSL-'version'...], where 'version' is the
OpenSSL version number with underscores instead of periods.
Windows: C:\Program Files\OpenSSL or C:\Program Files (x86)\OpenSSL
If you want to install it anywhere else, run config like this:
On Unix:
$ ./config --prefix=/opt/openssl --openssldir=/usr/local/ssl
On OpenVMS:
$ @config --prefix=PROGRAM:[INSTALLS] --openssldir=SYS$MANAGER:[OPENSSL]
(Note: if you do add options to the configuration command, please make sure
you've read more than just this Quick Start, such as relevant NOTES.* files,
the options outline below, as configuration options may change the outcome
in otherwise unexpected ways)
Configuration Options
There are several options to ./config (or ./Configure) to customize
the build (note that for Windows, the defaults for --prefix and
--openssldir depend in what configuration is used and what Windows
implementation OpenSSL is built on. More notes on this in NOTES.WIN):
Don't build with support for deprecated APIs below the
specified version number. For example "--api=1.1.0" will
remove support for all APIS that were deprecated in OpenSSL
version 1.1.0 or below.
The PREFIX to include in front of commands for your
toolchain. It's likely to have to end with dash, e.g.
a-b-c- would invoke GNU compiler as a-b-c-gcc, etc.
Unfortunately cross-compiling is too case-specific to
put together one-size-fits-all instructions. You might
have to pass more flags or set up environment variables
to actually make it work. Android and iOS cases are
discussed in corresponding Configurations/15-*.conf
files. But there are cases when this option alone is
sufficient. For example to build the mingw64 target on
Linux "--cross-compile-prefix=x86_64-w64-mingw32-"
works. Naturally provided that mingw packages are
installed. Today Debian and Ubuntu users have option to
install a number of prepackaged cross-compilers along
with corresponding run-time and development packages for
"alien" hardware. To give another example
"--cross-compile-prefix=mipsel-linux-gnu-" suffices
in such case. Needless to mention that you have to
invoke ./Configure, not ./config, and pass your target
name explicitly. Also, note that --openssldir refers
to target's file system, not one you are building on.
Build OpenSSL with debugging symbols and zero optimization
The name of the directory under the top of the installation
directory tree (see the --prefix option) where libraries will
be installed. By default this is "lib". Note that on Windows
only ".lib" files will be stored in this location. dll files
will always be installed to the "bin" directory.
Directory for OpenSSL configuration files, and also the
default certificate and key store. Defaults are:
Unix: /usr/local/ssl
Windows: C:\Program Files\Common Files\SSL
or C:\Program Files (x86)\Common Files\SSL
The top of the installation directory tree. Defaults are:
Unix: /usr/local
Windows: C:\Program Files\OpenSSL
or C:\Program Files (x86)\OpenSSL
Build OpenSSL without debugging symbols. This is the default.
This is a developer flag that switches on various compiler
options recommended for OpenSSL development. It only works
when using gcc or clang as the compiler. If you are
developing a patch for OpenSSL then it is recommended that
you use this option where possible.
The directory for the location of the zlib include file. This
option is only necessary if enable-zlib (see below) is used
and the include file is not already on the system include
On Unix: this is the directory containing the zlib library.
If not provided the system library path will be used.
On Windows: this is the filename of the zlib library (with or
without a path). This flag must be provided if the
zlib-dynamic option is not also used. If zlib-dynamic is used
then this flag is optional and a default value ("ZLIB1") is
used if not provided.
On VMS: this is the filename of the zlib library (with or
without a path). This flag is optional and if not provided
used by default depending on the pointer size chosen.
A comma separated list of seeding methods which will be tried
by OpenSSL in order to obtain random input (a.k.a "entropy")
for seeding its cryptographically secure random number
generator (CSPRNG). The current seeding methods are:
os: Use a trusted operating system entropy source.
This is the default method if such an entropy
source exists.
getrandom: Use the L<getrandom(2)> or equivalent system
devrandom: Use the the first device from the DEVRANDOM list
which can be opened to read random bytes. The
DEVRANDOM preprocessor constant expands to
"/dev/urandom","/dev/random","/dev/srandom" on
most unix-ish operating systems.
egd: Check for an entropy generating daemon.
rdcpu: Use the RDSEED or RDRAND command if provided by
the CPU.
librandom: Use librandom (not implemented yet).
none: Disable automatic seeding. This is the default
on some operating systems where no suitable
entropy source exists, or no support for it is
implemented yet.
For more information, see the section 'Note on random number
generation' at the end of this document.
Don't build the AFALG engine. This option will be forced if
on a platform that does not support AFALG.
Build with Kernel TLS support. This option will enable the
use of the Kernel TLS data-path, which can improve
performance and allow for the use of sendfile and splice
system calls on TLS sockets. The Kernel may use TLS
accelerators if any are available on the system.
This option will be forced off on systems that do not support
the Kernel TLS data-path.
Build with the Address sanitiser. This is a developer option
only. It may not work on all platforms and should never be
used in production environments. It will only work when used
with gcc or clang and should be used in conjunction with the
no-shared option.
Do not use assembler code. This should be viewed as
debugging/trouble-shooting option rather than production.
On some platforms a small amount of assembler code may
still be used even with this option.
Do not build support for async operations.
Don't automatically load all supported ciphers and digests.
Typically OpenSSL will make available all of its supported
ciphers and digests. For a statically linked application this
may be undesirable if small executable size is an objective.
This only affects libcrypto. Ciphers and digests will have to
be loaded manually using EVP_add_cipher() and
EVP_add_digest() if this option is used. This option will
force a non-shared build.
Don't automatically load all libcrypto/libssl error strings.
Typically OpenSSL will automatically load human readable
error strings. For a statically linked application this may
be undesirable if small executable size is an objective.
Don't automatically load the default openssl.cnf file.
Typically OpenSSL will automatically load a system config
file which configures default ssl options.
While testing, generate C++ buildtest files that
simply check that the public OpenSSL header files
are usable standalone with C++.
Enabling this option demands extra care. For any
compiler flag given directly as configuration
option, you must ensure that it's valid for both
the C and the C++ compiler. If not, the C++ build
test will most likely break. As an alternative,
you can use the language specific variables, CFLAGS
Don't build the CAPI engine. This option will be forced if
on a platform that does not support CAPI.
Don't build support for CMS features
Don't build support for SSL/TLS compression. If this option
is left enabled (the default), then compression will only
work if the zlib or zlib-dynamic options are also chosen.
Build support for debugging memory allocated via
OPENSSL_malloc() or OPENSSL_zalloc().
As for crypto-mdebug, but additionally provide backtrace
information for allocated memory.
TO BE USED WITH CARE: this uses GNU C functionality, and
is therefore not usable for non-GNU config targets. If
your build complains about the use of '-rdynamic' or the
lack of header file execinfo.h, this option is not for you.
ALSO NOTE that even though execinfo.h is available on your
system (through Gnulib), the functions might just be stubs
that do nothing.
Don't build support for Certificate Transparency.
Don't build with support for any deprecated APIs. This is the
same as using "--api" and supplying the latest version
Don't build support for datagram based BIOs. Selecting this
option will also force the disabling of DTLS.
Build the /dev/crypto engine. It is automatically selected
on BSD implementations, in which case it can be disabled with
Don't build the dynamically loaded engines. This only has an
effect in a "shared" build
Don't build support for Elliptic Curves.
Don't build support for binary Elliptic Curves
Enable support for optimised implementations of some commonly
used NIST elliptic curves.
This is only supported on platforms:
- with little-endian storage of non-byte types
- that tolerate misaligned memory references
- where the compiler:
- supports the non-standard type __uint128_t
- defines the built-in macro __SIZEOF_INT128__
Build support for gathering entropy from EGD (Entropy
Gathering Daemon).
Don't build support for loading engines.
Don't compile in any error strings.
Enable building of integration with external test suites.
This is a developer option and may not work on all platforms.
The only supported external test suite at the current time is
the BoringSSL test suite. See the file test/README.external
for further details.
Don't compile in filename and line number information (e.g.
for errors and memory allocation).
Don't compile the FIPS module
enable-fuzz-libfuzzer, enable-fuzz-afl
Build with support for fuzzing using either libfuzzer or AFL.
These are developer options only. They may not work on all
platforms and should never be used in production environments.
See the file fuzz/ for further details.
Don't build support for GOST based ciphersuites. Note that
if this feature is enabled then GOST ciphersuites are only
available if the GOST algorithms are also available through
loading an externally supplied engine.
Don't build the legacy provider. Disabling this also disables
the legacy algorithms: MD2 (already disabled by default).
Don't generate dependencies.
Don't build any dynamically loadable engines. This also
implies 'no-dynamic-engine'.
Don't build support for writing multiple records in one
go in libssl (Note: this is a different capability to the
pipelining functionality).
Don't build support for the NPN TLS extension.
Don't build support for OCSP.
Don't build the padlock engine.
('no-hw-padlock' is deprecated and should not be used)
Don't build with support for Position Independent Code.
no-pinshared By default OpenSSL will attempt to stay in memory until the
process exits. This is so that libcrypto and libssl can be
properly cleaned up automatically via an "atexit()" handler.
The handler is registered by libcrypto and cleans up both
libraries. On some platforms the atexit() handler will run on
unload of libcrypto (if it has been dynamically loaded)
rather than at process exit. This option can be used to stop
OpenSSL from attempting to stay in memory until the process
exits. This could lead to crashes if either libcrypto or
libssl have already been unloaded at the point
that the atexit handler is invoked, e.g. on a platform which
calls atexit() on unload of the library, and libssl is
unloaded before libcrypto then a crash is likely to happen.
Applications can suppress running of the atexit() handler at
run time by using the OPENSSL_INIT_NO_ATEXIT option to
OPENSSL_init_crypto(). See the man page for it for further
Don't use POSIX IO capabilities.
Don't build support for Pre-Shared Key based ciphersuites.
Don't use hardware RDRAND capabilities.
Don't build support for RFC3779 ("X.509 Extensions for IP
Addresses and AS Identifiers")
Build support for SCTP
Do not create shared libraries, only static ones. See "Note
on shared libraries" below.
Don't build support for socket BIOs
Don't build support for SRP or SRP based ciphersuites.
Don't build SRTP support
Exclude SSE2 code paths from 32-bit x86 assembly modules.
Normally SSE2 extension is detected at run-time, but the
decision whether or not the machine code will be executed
is taken solely on CPU capability vector. This means that
if you happen to run OS kernel which does not support SSE2
extension on Intel P4 processor, then your application
might be exposed to "illegal instruction" exception.
There might be a way to enable support in kernel, e.g.
FreeBSD kernel can be compiled with CPU_ENABLE_SSE, and
there is a way to disengage SSE2 code paths upon application
start-up, but if you aim for wider "audience" running
such kernel, consider no-sse2. Both the 386 and
no-asm options imply no-sse2.
Build with the SSL Trace capabilities (adds the "-trace"
option to s_client and s_server).
Don't build the statically linked engines. This only
has an impact when not built "shared".
Don't use anything from the C header file "stdio.h" that
makes use of the "FILE" type. Only libcrypto and libssl can
be built in this way. Using this option will suppress
building the command line applications. Additionally since
the OpenSSL tests also use the command line applications the
tests will also be skipped.
Don't build test programs or run any test.
Don't try to build with support for multi-threaded
Build with support for multi-threaded applications. Most
platforms will enable this by default. However if on a
platform where this is not the case then this will usually
require additional system-dependent options! See "Note on
multi-threading" below.
Build with support for the integrated tracing api. See manual pages
OSSL_trace_set_channel(3) and OSSL_trace_enabled(3) for details.
Don't build Time Stamping Authority support.
Build with the Undefined Behaviour sanitiser. This is a
developer option only. It may not work on all platforms and
should never be used in production environments. It will only
work when used with gcc or clang and should be used in
conjunction with the "-DPEDANTIC" option (or the
--strict-warnings option).
Don't build with the "UI" capability (i.e. the set of
features enabling text based prompts).
Enable additional unit test APIs. This should not typically
be used in production deployments.
Build support for SSL/TLS ciphers that are considered "weak"
(e.g. RC4 based ciphersuites).
Build with support for zlib compression/decompression.
Like "zlib", but has OpenSSL load the zlib library
dynamically when needed. This is only supported on systems
where loading of shared libraries is supported.
In 32-bit x86 builds, when generating assembly modules,
use the 80386 instruction set only (the default x86 code
is more efficient, but requires at least a 486). Note:
This doesn't affect code generated by compiler, you're
likely to complement configuration command line with
suitable compiler-specific option.
Don't build support for negotiating the specified SSL/TLS
protocol (one of ssl, ssl3, tls, tls1, tls1_1, tls1_2,
tls1_3, dtls, dtls1 or dtls1_2). If "no-tls" is selected then
all of tls1, tls1_1, tls1_2 and tls1_3 are disabled.
Similarly "no-dtls" will disable dtls1 and dtls1_2. The
"no-ssl" option is synonymous with "no-ssl3". Note this only
affects version negotiation. OpenSSL will still provide the
methods for applications to explicitly select the individual
protocol versions.
As for no-<prot> but in addition do not build the methods for
applications to explicitly select individual protocol
versions. Note that there is no "no-tls1_3-method" option
because there is no application method for TLSv1.3. Using
individual protocol methods directly is deprecated.
Applications should use TLS_method() instead.
Build with support for the specified algorithm, where <alg>
is one of: md2 or rc5.
Build without support for the specified algorithm, where
<alg> is one of: aria, bf, blake2, camellia, cast, chacha,
cmac, des, dh, dsa, ecdh, ecdsa, idea, md4, mdc2, ocb,
poly1305, rc2, rc4, rmd160, scrypt, seed, siphash, siv, sm2,
sm3, sm4 or whirlpool. The "ripemd" algorithm is deprecated
and if used is synonymous with rmd160.
-Dxxx, -Ixxx, -Wp, -lxxx, -Lxxx, -Wl, -rpath, -R, -framework, -static
These system specific options will be recognised and
passed through to the compiler to allow you to define
preprocessor symbols, specify additional libraries, library
directories or other compiler options. It might be worth
noting that some compilers generate code specifically for
processor the compiler currently executes on. This is not
necessarily what you might have in mind, since it might be
unsuitable for execution on other, typically older,
processor. Consult your compiler documentation.
Take note of the VAR=value documentation below and how
these flags interact with those variables.
-xxx, +xxx
Additional options that are not otherwise recognised are
passed through as they are to the compiler as well. Again,
consult your compiler documentation.
Take note of the VAR=value documentation below and how
these flags interact with those variables.
Assignment of environment variable for Configure. These
work just like normal environment variable assignments,
but are supported on all platforms and are confined to
the configuration scripts only. These assignments override
the corresponding value in the inherited environment, if
there is one.
The following variables are used as "make variables" and
can be used as an alternative to giving preprocessor,
compiler and linker options directly as configuration.
The following variables are supported:
AR The static library archiver.
ARFLAGS Flags for the static library archiver.
AS The assembler compiler.
ASFLAGS Flags for the assembler compiler.
CC The C compiler.
CFLAGS Flags for the C compiler.
CXX The C++ compiler.
CXXFLAGS Flags for the C++ compiler.
CPP The C/C++ preprocessor.
CPPFLAGS Flags for the C/C++ preprocessor.
CPPDEFINES List of CPP macro definitions, separated
by a platform specific character (':' or
space for Unix, ';' for Windows, ',' for
VMS). This can be used instead of using
-D (or what corresponds to that on your
compiler) in CPPFLAGS.
CPPINCLUDES List of CPP inclusion directories, separated
the same way as for CPPDEFINES. This can
be used instead of -I (or what corresponds
to that on your compiler) in CPPFLAGS.
HASHBANGPERL Perl invocation to be inserted after '#!'
in public perl scripts (only relevant on
LD The program linker (not used on Unix, $(CC)
is used there).
LDFLAGS Flags for the shared library, DSO and
program linker.
LDLIBS Extra libraries to use when linking.
Takes the form of a space separated list
of library specifications on Unix and
Windows, and as a comma separated list of
libraries on VMS.
RANLIB The library archive indexer.
RC The Windows resource compiler.
RCFLAGS Flags for the Windows resource compiler.
RM The command to remove files and directories.
These cannot be mixed with compiling / linking flags given
on the command line. In other words, something like this
isn't permitted.
Backward compatibility note:
To be compatible with older configuration scripts, the
environment variables are ignored if compiling / linking
flags are given on the command line, except for these:
For example, the following command will not see -DBAR:
However, the following will see both set variables:
CC=gcc CROSS_COMPILE=x86_64-w64-mingw32- \
./config -DCOOKIE
If CC is set, it is advisable to also set CXX to ensure
both C and C++ compilers are in the same "family". This
becomes relevant with 'enable-external-tests' and
Reconfigure from earlier data. This fetches the previous
command line options and environment from data saved in
"", and runs the configuration process again,
using these options and environment.
Note: NO other option is permitted together with "reconf".
This means that you also MUST use "./Configure" (or
what corresponds to that on non-Unix platforms) directly
to invoke this option.
Note: The original configuration saves away values for ALL
environment variables that were used, and if they weren't
defined, they are still saved away with information that
they weren't originally defined. This information takes
precedence over environment variables that are defined
when reconfiguring.
Displaying configuration data
The configuration script itself will say very little, and finishes by
creating "". This perl module can be loaded by other scripts
to find all the configuration data, and it can also be used as a script to
display all sorts of configuration data in a human readable form.
For more information, please do:
$ ./ --help # Unix
$ perl --help # Windows and VMS
Installation in Detail
1a. Configure OpenSSL for your operation system automatically:
NOTE: This is not available on Windows.
$ ./config [[ options ]] # Unix
$ @config [[ options ]] ! OpenVMS
For the remainder of this text, the Unix form will be used in all
examples, please use the appropriate form for your platform.
This guesses at your operating system (and compiler, if necessary) and
configures OpenSSL based on this guess. Run ./config -t to see
if it guessed correctly. If you want to use a different compiler, you
are cross-compiling for another platform, or the ./config guess was
wrong for other reasons, go to step 1b. Otherwise go to step 2.
On some systems, you can include debugging information as follows:
$ ./config -d [[ options ]]
1b. Configure OpenSSL for your operating system manually
OpenSSL knows about a range of different operating system, hardware and
compiler combinations. To see the ones it knows about, run
$ ./Configure # Unix
$ perl Configure # All other platforms
For the remainder of this text, the Unix form will be used in all
examples, please use the appropriate form for your platform.
Pick a suitable name from the list that matches your system. For most
operating systems there is a choice between using "cc" or "gcc". When
you have identified your system (and if necessary compiler) use this name
as the argument to Configure. For example, a "linux-elf" user would
$ ./Configure linux-elf [[ options ]]
If your system isn't listed, you will have to create a configuration
file named Configurations/{{ something }}.conf and add the correct
configuration for your system. See the available configs as examples
and read Configurations/README and Configurations/ for
more information.
The generic configurations "cc" or "gcc" should usually work on 32 bit
Unix-like systems.
Configure creates a build file ("Makefile" on Unix, "makefile" on Windows
and "descrip.mms" on OpenVMS) from a suitable template in Configurations,
and defines various macros in include/openssl/opensslconf.h (generated from
1c. Configure OpenSSL for building outside of the source tree.
OpenSSL can be configured to build in a build directory separate from
the directory with the source code. It's done by placing yourself in
some other directory and invoking the configuration commands from
Unix example:
$ mkdir /var/tmp/openssl-build
$ cd /var/tmp/openssl-build
$ /PATH/TO/OPENSSL/SOURCE/config [[ options ]]
$ /PATH/TO/OPENSSL/SOURCE/Configure {{ target }} [[ options ]]
OpenVMS example:
$ set default sys$login:
$ create/dir [.tmp.openssl-build]
$ set default [.tmp.openssl-build]
$ @[PATH.TO.OPENSSL.SOURCE]config [[ options ]]
$ @[PATH.TO.OPENSSL.SOURCE]Configure {{ target }} [[ options ]]
Windows example:
$ C:
$ mkdir \temp-openssl
$ cd \temp-openssl
$ perl d:\PATH\TO\OPENSSL\SOURCE\Configure {{ target }} [[ options ]]
Paths can be relative just as well as absolute. Configure will
do its best to translate them to relative paths whenever possible.
2. Build OpenSSL by running:
$ make # Unix
$ mms ! (or mmk) OpenVMS
$ nmake # Windows
This will build the OpenSSL libraries (libcrypto.a and libssl.a on
Unix, corresponding on other platforms) and the OpenSSL binary
("openssl"). The libraries will be built in the top-level directory,
and the binary will be in the "apps" subdirectory.
If the build fails, look at the output. There may be reasons
for the failure that aren't problems in OpenSSL itself (like
missing standard headers).
If the build succeeded previously, but fails after a source or
configuration change, it might be helpful to clean the build tree
before attempting another build. Use this command:
$ make clean # Unix
$ mms clean ! (or mmk) OpenVMS
$ nmake clean # Windows
Assembler error messages can sometimes be sidestepped by using the
"no-asm" configuration option.
Compiling parts of OpenSSL with gcc and others with the system
compiler will result in unresolved symbols on some systems.
If you are still having problems you can get help by sending an email
to the openssl-users email list (see for details). If
it is a bug with OpenSSL itself, please open an issue on GitHub, at Please review the existing
ones first; maybe the bug was already reported or has already been
3. After a successful build, the libraries should be tested. Run:
$ make test # Unix
$ mms test ! OpenVMS
$ nmake test # Windows
NOTE: you MUST run the tests from an unprivileged account (or
disable your privileges temporarily if your platform allows it).
If some tests fail, look at the output. There may be reasons for
the failure that isn't a problem in OpenSSL itself (like a
malfunction with Perl). You may want increased verbosity, that
can be accomplished like this:
$ make VERBOSE=1 test # Unix
$ mms /macro=(VERBOSE=1) test ! OpenVMS
$ nmake VERBOSE=1 test # Windows
If you want to run just one or a few specific tests, you can use
the make variable TESTS to specify them, like this:
$ make TESTS='test_rsa test_dsa' test # Unix
$ mms/macro="TESTS=test_rsa test_dsa" test ! OpenVMS
$ nmake TESTS='test_rsa test_dsa' test # Windows
And of course, you can combine (Unix example shown):
$ make VERBOSE=1 TESTS='test_rsa test_dsa' test
You can find the list of available tests like this:
$ make list-tests # Unix
$ mms list-tests ! OpenVMS
$ nmake list-tests # Windows
Have a look at the manual for the perl module Test::Harness to
see what other HARNESS_* variables there are.
If you find a problem with OpenSSL itself, try removing any
compiler optimization flags from the CFLAGS line in Makefile and
run "make clean; make" or corresponding.
To report a bug please open an issue on GitHub, at
For more details on how the make variables TESTS can be used,
see section TESTS in Detail below.
4. If everything tests ok, install OpenSSL with
$ make install # Unix
$ mms install ! OpenVMS
$ nmake install # Windows
This will install all the software components in this directory
tree under PREFIX (the directory given with --prefix or its
bin/ Contains the openssl binary and a few other
utility scripts.
Contains the header files needed if you want
to build your own programs that use libcrypto
or libssl.
lib Contains the OpenSSL library files.
lib/engines Contains the OpenSSL dynamically loadable engines.
share/man/man1 Contains the OpenSSL command line man-pages.
share/man/man3 Contains the OpenSSL library calls man-pages.
share/man/man5 Contains the OpenSSL configuration format man-pages.
share/man/man7 Contains the OpenSSL other misc man-pages.
Contains the HTML rendition of the man-pages.
OpenVMS ('arch' is replaced with the architecture name, "Alpha"
or "ia64", 'sover' is replaced with the shared library version
(0101 for 1.1), and 'pz' is replaced with the pointer size
OpenSSL was built with):
[.EXE.'arch'] Contains the openssl binary.
[.EXE] Contains a few utility scripts.
Contains the header files needed if you want
to build your own programs that use libcrypto
or libssl.
[.LIB.'arch'] Contains the OpenSSL library files.
Contains the OpenSSL dynamically loadable engines.
[.SYS$STARTUP] Contains startup, login and shutdown scripts.
These define appropriate logical names and
command symbols.
[.SYSTEST] Contains the installation verification procedure.
[.HTML] Contains the HTML rendition of the manual pages.
Additionally, install will add the following directories under
OPENSSLDIR (the directory given with --openssldir or its default)
for you convenience:
certs Initially empty, this is the default location
for certificate files.
private Initially empty, this is the default location
for private key files.
misc Various scripts.
Package builders who want to configure the library for standard
locations, but have the package installed somewhere else so that
it can easily be packaged, can use
$ make DESTDIR=/tmp/package-root install # Unix
$ mms/macro="DESTDIR=TMP:[PACKAGE-ROOT]" install ! OpenVMS
The specified destination directory will be prepended to all
installation target paths.
Compatibility issues with previous OpenSSL versions:
* COMPILING existing applications
Starting with version 1.1.0, OpenSSL hides a number of structures
that were previously open. This includes all internal libssl
structures and a number of EVP types. Accessor functions have
been added to allow controlled access to the structures' data.
This means that some software needs to be rewritten to adapt to
the new ways of doing things. This often amounts to allocating
an instance of a structure explicitly where you could previously
allocate them on the stack as automatic variables, and using the
provided accessor functions where you would previously access a
structure's field directly.
Some APIs have changed as well. However, older APIs have been
preserved when possible.
Environment Variables
A number of environment variables can be used to provide additional control
over the build process. Typically these should be defined prior to running
config or Configure. Not all environment variables are relevant to all
The name of the ar executable to use.
Use a different build file name than the platform default
("Makefile" on Unix-like platforms, "makefile" on native Windows,
"descrip.mms" on OpenVMS). This requires that there is a
corresponding build file template. See Configurations/README
for further information.
The compiler to use. Configure will attempt to pick a default
compiler for your platform but this choice can be overridden
using this variable. Set it to the compiler executable you wish
to use, e.g. "gcc" or "clang".
This environment variable has the same meaning as for the
"--cross-compile-prefix" Configure flag described above. If both
are set then the Configure flag takes precedence.
The name of the nm executable to use.
OpenSSL comes with a database of information about how it
should be built on different platforms as well as build file
templates for those platforms. The database is comprised of
".conf" files in the Configurations directory. The build
file templates reside there as well as ".tmpl" files. See the
file Configurations/README for further information about the
format of ".conf" files as well as information on the ".tmpl"
In addition to the standard ".conf" and ".tmpl" files, it is
possible to create your own ".conf" and ".tmpl" files and store
them locally, outside the OpenSSL source tree. This environment
variable can be set to the directory where these files are held
and will be considered by Configure before it looks in the
standard directories.
The name of the Perl executable to use when building OpenSSL.
This variable is used in config script only. Configure on the
other hand imposes the interpreter by which it itself was
executed on the whole build procedure.
The command string for the Perl executable to insert in the
#! line of perl scripts that will be publically installed.
Default: /usr/bin/env perl
Note: the value of this variable is added to the same scripts
on all platforms, but it's only relevant on Unix-like platforms.
The name of the rc executable to use. The default will be as
defined for the target platform in the ".conf" file. If not
defined then "windres" will be used. The WINDRES environment
variable is synonymous to this. If both are defined then RC
takes precedence.
The name of the ranlib executable to use.
See RC.
Makefile targets
The Configure script generates a Makefile in a format relevant to the specific
platform. The Makefiles provide a number of targets that can be used. Not all
targets may be available on all platforms. Only the most common targets are
described here. Examine the Makefiles themselves for the full list.
The default target to build all the software components.
Remove all build artefacts and return the directory to a "clean"
Rebuild the dependencies in the Makefiles. This is a legacy
option that no longer needs to be used since OpenSSL 1.1.0.
Install all OpenSSL components.
Only install the OpenSSL software components.
Only install the OpenSSL documentation components.
Only install the OpenSSL man pages (Unix only).
Only install the OpenSSL html documentation.
Prints a list of all the self test names.
Build and run the OpenSSL self tests.
Uninstall all OpenSSL components.
Re-run the configuration process, as exactly as the last time
as possible.
This is a developer option. If you are developing a patch for
OpenSSL you may need to use this if you want to update
automatically generated files; add new error codes or add new
(or change the visibility of) public API functions. (Unix only).
TESTS in Detail
The make variable TESTS supports a versatile set of space separated tokens
with which you can specify a set of tests to be performed. With a "current
set of tests" in mind, initially being empty, here are the possible tokens:
alltests The current set of tests becomes the whole set of available
tests (as listed when you do 'make list-tests' or similar).
xxx Adds the test 'xxx' to the current set of tests.
-xxx Removes 'xxx' from the current set of tests. If this is the
first token in the list, the current set of tests is first
assigned the whole set of available tests, effectively making
this token equivalent to TESTS="alltests -xxx".
nn Adds the test group 'nn' (which is a number) to the current
set of tests.
-nn Removes the test group 'nn' from the current set of tests.
If this is the first token in the list, the current set of
tests is first assigned the whole set of available tests,
effectively making this token equivalent to
TESTS="alltests -xxx".
Also, all tokens except for "alltests" may have wildcards, such as *.
(on Unix and Windows, BSD style wildcards are supported, while on VMS,
it's VMS style wildcards)
Example: All tests except for the fuzz tests:
$ make TESTS=-test_fuzz test
or (if you want to be explicit)
$ make TESTS='alltests -test_fuzz' test
Example: All tests that have a name starting with "test_ssl" but not those
starting with "test_ssl_":
$ make TESTS='test_ssl* -test_ssl_*' test
Example: Only test group 10:
$ make TESTS='10'
Example: All tests except the slow group (group 99):
$ make TESTS='-99'
Example: All tests in test groups 80 to 99 except for tests in group 90:
$ make TESTS='[89]? -90'
Note on multi-threading
For some systems, the OpenSSL Configure script knows what compiler options
are needed to generate a library that is suitable for multi-threaded
applications. On these systems, support for multi-threading is enabled
by default; use the "no-threads" option to disable (this should never be
On other systems, to enable support for multi-threading, you will have
to specify at least two options: "threads", and a system-dependent option.
(The latter is "-D_REENTRANT" on various systems.) The default in this
case, obviously, is not to include support for multi-threading (but
you can still use "no-threads" to suppress an annoying warning message
from the Configure script.)
OpenSSL provides built-in support for two threading models: pthreads (found on
most UNIX/Linux systems), and Windows threads. No other threading models are
supported. If your platform does not provide pthreads or Windows threads then
you should Configure with the "no-threads" option.
Notes on shared libraries
For most systems the OpenSSL Configure script knows what is needed to
build shared libraries for libcrypto and libssl. On these systems
the shared libraries will be created by default. This can be suppressed and
only static libraries created by using the "no-shared" option. On systems
where OpenSSL does not know how to build shared libraries the "no-shared"
option will be forced and only static libraries will be created.
Shared libraries are named a little differently on different platforms.
One way or another, they all have the major OpenSSL version number as
part of the file name, i.e. for OpenSSL 1.1.x, 1.1 is somehow part of
the name.
On most POSIX platforms, shared libraries are named
on Cygwin, shared libraries are named cygcrypto-1.1.dll and cygssl-1.1.dll
with import libraries libcrypto.dll.a and libssl.dll.a.
On Windows build with MSVC or using MingW, shared libraries are named
libcrypto-1_1.dll and libssl-1_1.dll for 32-bit Windows, libcrypto-1_1-x64.dll
and libssl-1_1-x64.dll for 64-bit x86_64 Windows, and libcrypto-1_1-ia64.dll
and libssl-1_1-ia64.dll for IA64 Windows. With MSVC, the import libraries
are named libcrypto.lib and libssl.lib, while with MingW, they are named
libcrypto.dll.a and libssl.dll.a.
On VMS, shareable images (VMS speak for shared libraries) are named
ossl$libcrypto0101_shr.exe and ossl$libssl0101_shr.exe. However, when
OpenSSL is specifically built for 32-bit pointers, the shareable images
are named ossl$libcrypto0101_shr32.exe and ossl$libssl0101_shr32.exe
instead, and when built for 64-bit pointers, they are named
ossl$libcrypto0101_shr64.exe and ossl$libssl0101_shr64.exe.
Note on random number generation
Availability of cryptographically secure random numbers is required for
secret key generation. OpenSSL provides several options to seed the
internal CSPRNG. If not properly seeded, the internal CSPRNG will refuse
to deliver random bytes and a "PRNG not seeded error" will occur.
The seeding method can be configured using the --with-rand-seed option,
which can be used to specify a comma separated list of seed methods.
However in most cases OpenSSL will choose a suitable default method,
so it is not necessary to explicitly provide this option. Note also
that not all methods are available on all platforms.
I) On operating systems which provide a suitable randomness source (in
form of a system call or system device), OpenSSL will use the optimal
available method to seed the CSPRNG from the operating system's
randomness sources. This corresponds to the option --with-rand-seed=os.
II) On systems without such a suitable randomness source, automatic seeding
and reseeding is disabled (--with-rand-seed=none) and it may be necessary
to install additional support software to obtain a random seed and reseed
the CSPRNG manually. Please check out the manual pages for RAND_add(),
RAND_bytes(), RAND_egd(), and the FAQ for more information.
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