FAQ - third_party/openssl - Git at Google

 OpenSSL  -  Frequently Asked Questions
 --------------------------------------

 * Which is the current version of OpenSSL?
 * Where is the documentation?
 * How can I contact the OpenSSL developers?
 * Do I need patent licenses to use OpenSSL?
 * Is OpenSSL thread-safe?
 * Why do I get a "PRNG not seeded" error message?
 * Why does the linker complain about undefined symbols?
 * Where can I get a compiled version of OpenSSL?


 * Which is the current version of OpenSSL?

 The current version is available from <URL: http://www.openssl.org>.
 OpenSSL 0.9.5 was released on February 28th, 2000.

 In addition to the current stable release, you can also access daily
 snapshots of the OpenSSL development version at <URL:
 ftp://ftp.openssl.org/snapshot/>, or get it by anonymous CVS access.


 * Where is the documentation?

 OpenSSL is a library that provides cryptographic functionality to
 applications such as secure web servers.  Be sure to read the
 documentation of the application you want to use.  The INSTALL file
 explains how to install this library.

 OpenSSL includes a command line utility that can be used to perform a
 variety of cryptographic functions.  It is described in the openssl(1)
 manpage.  Documentation for developers is currently being written.  A
 few manual pages already are available; overviews over libcrypto and
 libssl are given in the crypto(3) and ssl(3) manpages.

 The OpenSSL manpages are installed in /usr/local/ssl/man/ (or a
 different directory if you specified one as described in INSTALL).
 In addition, you can read the most current versions at
 <URL: http://www.openssl.org/docs/>.

 For information on parts of libcrypto that are not yet documented, you
 might want to read Ariel Glenn's documentation on SSLeay 0.9, OpenSSL's
 predecessor, at <URL: http://www.columbia.edu/~ariel/ssleay/>.  Much
 of this still applies to OpenSSL.

 There is some documentation about certificate extensions and PKCS#12
 in doc/openssl.txt

 The original SSLeay documentation is included in OpenSSL as
 doc/ssleay.txt.  It may be useful when none of the other resources
 help, but please note that it reflects the obsolete version SSLeay
 0.6.6.


 * How can I contact the OpenSSL developers?

 The README file describes how to submit bug reports and patches to
 OpenSSL.  Information on the OpenSSL mailing lists is available from
 <URL: http://www.openssl.org>.


 * Do I need patent licenses to use OpenSSL?

 The patents section of the README file lists patents that may apply to
 you if you want to use OpenSSL.  For information on intellectual
 property rights, please consult a lawyer.  The OpenSSL team does not
 offer legal advice.

 You can configure OpenSSL so as not to use RC5 and IDEA by using
  ./config no-rc5 no-idea

 Until the RSA patent expires, U.S. users may want to use
  ./config no-rc5 no-idea no-rsa

 Please note that you will *not* be able to communicate with most of
 the popular web browsers without RSA support.


 * Is OpenSSL thread-safe?

 Yes (with limitations: an SSL connection may not concurrently be used
 by multiple threads).  On Windows and many Unix systems, OpenSSL
 automatically uses the multi-threaded versions of the standard
 libraries.  If your platform is not one of these, consult the INSTALL
 file.

 Multi-threaded applications must provide two callback functions to
 OpenSSL.  This is described in the threads(3) manpage.


 * Why do I get a "PRNG not seeded" error message?

 Cryptographic software needs a source of unpredictable data to work
 correctly.  Many open source operating systems provide a "randomness
 device" that serves this purpose.  On other systems, applications have
 to call the RAND_add() or RAND_seed() function with appropriate data
 before generating keys or performing public key encryption.

 Some broken applications do not do this.  As of version 0.9.5, the
 OpenSSL functions that need randomness report an error if the random
 number generator has not been seeded with at least 128 bits of
 randomness.  If this error occurs, please contact the author of the
 application you are using.  It is likely that it never worked
 correctly.  OpenSSL 0.9.5 makes the error visible by refusing to
 perform potentially insecure encryption.

 Most components of the openssl command line tool try to use the
 file $HOME/.rnd (or $RANDFILE, if this environment variable is set)
 for seeding the PRNG.  If this file does not exist or is too short,
 the "PRNG not seeded" error message may occur.
 Note that the command "openssl rsa" in OpenSSL 0.9.5 does not do this
 and will fail on systems without /dev/urandom when trying to
 password-encrypt an RSA key!  This is a bug in the library;
 try a later snaphost instead.


 * Why does the linker complain about undefined symbols?

 Maybe the compilation was interrupted, and make doesn't notice that
 something is missing.  Run "make clean; make".

 If you used ./Configure instead of ./config, make sure that you
 selected the right target.  File formats may differ slightly between
 OS versions (for example sparcv8/sparcv9, or a.out/elf).

 In case you get errors about the following symbols, use the config
 option "no-asm", as described in INSTALL:

  BF_cbc_encrypt, BF_decrypt, BF_encrypt, CAST_cbc_encrypt,
  CAST_decrypt, CAST_encrypt, RC4, RC5_32_cbc_encrypt, RC5_32_decrypt,
  RC5_32_encrypt, bn_add_words, bn_div_words, bn_mul_add_words,
  bn_mul_comba4, bn_mul_comba8, bn_mul_words, bn_sqr_comba4,
  bn_sqr_comba8, bn_sqr_words, bn_sub_words, des_decrypt3,
  des_ede3_cbc_encrypt, des_encrypt, des_encrypt2, des_encrypt3,
  des_ncbc_encrypt, md5_block_asm_host_order, sha1_block_asm_data_order

 If none of these helps, you may want to try using the current snapshot.
 If the problem persists, please submit a bug report.


 * Where can I get a compiled version of OpenSSL?

 Some applications that use OpenSSL are distributed in binary form.
 When using such an application, you don't need to install OpenSSL
 yourself; the application will include the required parts (e.g. DLLs).

 If you want to install OpenSSL on a Windows system and you don't have
 a C compiler, read the "Mingw32" section of INSTALL.W32 for information
 on how to obtain and install the free GNU C compiler.

 A number of Linux and *BSD distributions include OpenSSL.
	OpenSSL - Frequently Asked Questions
	--------------------------------------

	* Which is the current version of OpenSSL?
	* Where is the documentation?
	* How can I contact the OpenSSL developers?
	* Do I need patent licenses to use OpenSSL?
	* Is OpenSSL thread-safe?
	* Why do I get a "PRNG not seeded" error message?
	* Why does the linker complain about undefined symbols?
	* Where can I get a compiled version of OpenSSL?


	* Which is the current version of OpenSSL?

	The current version is available from <URL: http://www.openssl.org>.
	OpenSSL 0.9.5 was released on February 28th, 2000.

	In addition to the current stable release, you can also access daily
	snapshots of the OpenSSL development version at <URL:
	ftp://ftp.openssl.org/snapshot/>, or get it by anonymous CVS access.


	* Where is the documentation?

	OpenSSL is a library that provides cryptographic functionality to
	applications such as secure web servers. Be sure to read the
	documentation of the application you want to use. The INSTALL file
	explains how to install this library.

	OpenSSL includes a command line utility that can be used to perform a
	variety of cryptographic functions. It is described in the openssl(1)
	manpage. Documentation for developers is currently being written. A
	few manual pages already are available; overviews over libcrypto and
	libssl are given in the crypto(3) and ssl(3) manpages.

	The OpenSSL manpages are installed in /usr/local/ssl/man/ (or a
	different directory if you specified one as described in INSTALL).
	In addition, you can read the most current versions at
	<URL: http://www.openssl.org/docs/>.

	For information on parts of libcrypto that are not yet documented, you
	might want to read Ariel Glenn's documentation on SSLeay 0.9, OpenSSL's
	predecessor, at <URL: http://www.columbia.edu/~ariel/ssleay/>. Much
	of this still applies to OpenSSL.

	There is some documentation about certificate extensions and PKCS#12
	in doc/openssl.txt

	The original SSLeay documentation is included in OpenSSL as
	doc/ssleay.txt. It may be useful when none of the other resources
	help, but please note that it reflects the obsolete version SSLeay
	0.6.6.


	* How can I contact the OpenSSL developers?

	The README file describes how to submit bug reports and patches to
	OpenSSL. Information on the OpenSSL mailing lists is available from
	<URL: http://www.openssl.org>.


	* Do I need patent licenses to use OpenSSL?

	The patents section of the README file lists patents that may apply to
	you if you want to use OpenSSL. For information on intellectual
	property rights, please consult a lawyer. The OpenSSL team does not
	offer legal advice.

	You can configure OpenSSL so as not to use RC5 and IDEA by using
	./config no-rc5 no-idea

	Until the RSA patent expires, U.S. users may want to use
	./config no-rc5 no-idea no-rsa

	Please note that you will not be able to communicate with most of
	the popular web browsers without RSA support.


	* Is OpenSSL thread-safe?

	Yes (with limitations: an SSL connection may not concurrently be used
	by multiple threads). On Windows and many Unix systems, OpenSSL
	automatically uses the multi-threaded versions of the standard
	libraries. If your platform is not one of these, consult the INSTALL
	file.

	Multi-threaded applications must provide two callback functions to
	OpenSSL. This is described in the threads(3) manpage.


	* Why do I get a "PRNG not seeded" error message?

	Cryptographic software needs a source of unpredictable data to work
	correctly. Many open source operating systems provide a "randomness
	device" that serves this purpose. On other systems, applications have
	to call the RAND_add() or RAND_seed() function with appropriate data
	before generating keys or performing public key encryption.

	Some broken applications do not do this. As of version 0.9.5, the
	OpenSSL functions that need randomness report an error if the random
	number generator has not been seeded with at least 128 bits of
	randomness. If this error occurs, please contact the author of the
	application you are using. It is likely that it never worked
	correctly. OpenSSL 0.9.5 makes the error visible by refusing to
	perform potentially insecure encryption.

	Most components of the openssl command line tool try to use the
	file $HOME/.rnd (or $RANDFILE, if this environment variable is set)
	for seeding the PRNG. If this file does not exist or is too short,
	the "PRNG not seeded" error message may occur.
	Note that the command "openssl rsa" in OpenSSL 0.9.5 does not do this
	and will fail on systems without /dev/urandom when trying to
	password-encrypt an RSA key! This is a bug in the library;
	try a later snaphost instead.


	* Why does the linker complain about undefined symbols?

	Maybe the compilation was interrupted, and make doesn't notice that
	something is missing. Run "make clean; make".

	If you used ./Configure instead of ./config, make sure that you
	selected the right target. File formats may differ slightly between
	OS versions (for example sparcv8/sparcv9, or a.out/elf).

	In case you get errors about the following symbols, use the config
	option "no-asm", as described in INSTALL:

	BF_cbc_encrypt, BF_decrypt, BF_encrypt, CAST_cbc_encrypt,
	CAST_decrypt, CAST_encrypt, RC4, RC5_32_cbc_encrypt, RC5_32_decrypt,
	RC5_32_encrypt, bn_add_words, bn_div_words, bn_mul_add_words,
	bn_mul_comba4, bn_mul_comba8, bn_mul_words, bn_sqr_comba4,
	bn_sqr_comba8, bn_sqr_words, bn_sub_words, des_decrypt3,
	des_ede3_cbc_encrypt, des_encrypt, des_encrypt2, des_encrypt3,
	des_ncbc_encrypt, md5_block_asm_host_order, sha1_block_asm_data_order

	If none of these helps, you may want to try using the current snapshot.
	If the problem persists, please submit a bug report.


	* Where can I get a compiled version of OpenSSL?

	Some applications that use OpenSSL are distributed in binary form.
	When using such an application, you don't need to install OpenSSL
	yourself; the application will include the required parts (e.g. DLLs).

	If you want to install OpenSSL on a Windows system and you don't have
	a C compiler, read the "Mingw32" section of INSTALL.W32 for information
	on how to obtain and install the free GNU C compiler.

	A number of Linux and *BSD distributions include OpenSSL.