* Why does my browser give a warning about a mismatched hostname?
* How do I install a CA certificate into a browser?
* Why is OpenSSL x509 DN output not conformant to RFC2253?
+* What is a "128 bit certificate"? Can I create one with OpenSSL?
[BUILD] Questions about building and testing OpenSSL
* Why does the OpenSSL test suite fail on MacOS X?
* Why does the OpenSSL test suite fail in BN_sqr test [on a 64-bit platform]?
* Why does OpenBSD-i386 build fail on des-586.s with "Unimplemented segment type"?
+* Why does the OpenSSL test suite fail in sha512t on x86 CPU?
+* Why does compiler fail to compile sha512.c?
[PROG] Questions about programming with OpenSSL
* Which is the current version of OpenSSL?
The current version is available from <URL: http://www.openssl.org>.
-OpenSSL 0.9.7e was released on October 25, 2004.
+OpenSSL 0.9.8a was released on October 11th, 2005.
In addition to the current stable release, you can also access daily
snapshots of the OpenSSL development version at <URL:
With version 0.9.6 OpenSSL was extended to interface to external crypto
hardware. This was realized in a special release '0.9.6-engine'. With
-version 0.9.7 (not yet released) the changes were merged into the main
-development line, so that the special release is no longer necessary.
+version 0.9.7 the changes were merged into the main development line,
+so that the special release is no longer necessary.
* How do I check the authenticity of the OpenSSL distribution?
md5sum TARBALL | awk '{print $1;}' | cmp - TARBALL.md5
You can check authenticity using pgp or gpg. You need the OpenSSL team
-member public key used to sign it (download it from a key server). Then
+member public key used to sign it (download it from a key server, see a
+list of keys at <URL: http://www.openssl.org/about/>). Then
just do:
pgp TARBALL.asc
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
+You can configure OpenSSL so as not to use IDEA, MDC2 and RC5 by using
+ ./config no-idea no-mdc2 no-rc5
* Can I use OpenSSL with GPL software?
page of the "openssl x509" commandline tool for details. The old behaviour
has however been left as default for the sake of compatibility.
+* What is a "128 bit certificate"? Can I create one with OpenSSL?
+
+The term "128 bit certificate" is a highly misleading marketing term. It does
+*not* refer to the size of the public key in the certificate! A certificate
+containing a 128 bit RSA key would have negligible security.
+
+There were various other names such as "magic certificates", "SGC
+certificates", "step up certificates" etc.
+
+You can't generally create such a certificate using OpenSSL but there is no
+need to any more. Nowadays web browsers using unrestricted strong encryption
+are generally available.
+
+When there were tight export restrictions on the export of strong encryption
+software from the US only weak encryption algorithms could be freely exported
+(initially 40 bit and then 56 bit). It was widely recognised that this was
+inadequate. A relaxation the rules allowed the use of strong encryption but
+only to an authorised server.
+
+Two slighly different techniques were developed to support this, one used by
+Netscape was called "step up", the other used by MSIE was called "Server Gated
+Cryptography" (SGC). When a browser initially connected to a server it would
+check to see if the certificate contained certain extensions and was issued by
+an authorised authority. If these test succeeded it would reconnect using
+strong encryption.
+
+Only certain (initially one) certificate authorities could issue the
+certificates and they generally cost more than ordinary certificates.
+
+Although OpenSSL can create certificates containing the appropriate extensions
+the certificate would not come from a permitted authority and so would not
+be recognized.
+
+The export laws were later changed to allow almost unrestricted use of strong
+encryption so these certificates are now obsolete.
+
+
[BUILD] =======================================================================
* Why does the linker complain about undefined symbols?
level chosen by the configuration process. When the above is done, do the
test and installation and you're set.
+3. Reconfigure the toolkit with no-sha0 option to leave out SHA0. It
+should not be used and is not used in SSL/TLS nor any other recognized
+protocol in either case.
+
* Why does the OpenSSL compilation fail with "ar: command not found"?
remedy should be same. Provided binary is statically linked and should be
working across wider range of *BSD branches, not just OpenBSD.
+* Why does the OpenSSL test suite fail in sha512t on x86 CPU?
+
+If the test program in question fails withs SIGILL, Illegal Instruction
+exception, then you more than likely to run SSE2-capable CPU, such as
+Intel P4, under control of kernel which does not support SSE2
+instruction extentions. See accompanying INSTALL file and
+OPENSSL_ia32cap(3) documentation page for further information.
+
+* Why does compiler fail to compile sha512.c?
+
+OpenSSL SHA-512 implementation depends on compiler support for 64-bit
+integer type. Few elder compilers [ULTRIX cc, SCO compiler to mention a
+couple] lack support for this and therefore are incapable of compiling
+the module in question. The recommendation is to disable SHA-512 by
+adding no-sha512 to ./config [or ./Configure] command line. Another
+possible alternative might be to switch to GCC.
+
[PROG] ========================================================================
* Is OpenSSL thread-safe?
Note that debug and release libraries are NOT interchangeable. If you
built OpenSSL with /MD your application must use /MD and cannot use /MDd.
+As per 0.9.8 the above limitation is eliminated for .DLLs. OpenSSL
+.DLLs compiled with some specific run-time option [we recommend the
+default /MD] can be deployed with application compiled with different
+option or even different compiler. But there is a catch! Instead of
+re-compiling OpenSSL toolkit, as you would have to with prior versions,
+you have to compile small C snippet with compiler and/or options of
+your choice. The snippet gets installed as
+<install-root>/include/openssl/applink.c and should be either added to
+your project or simply #include-d in one [and only one] of your source
+files. Failure to do either manifests itself as fatal "no
+OPENSSL_Applink" error.
* How do I read or write a DER encoded buffer using the ASN1 functions?
in size over time they are harmless.
These internal tables can be freed up when an application closes using various
-functions. Currently these include: EVP_cleanup(), ERR_remove_state(),
-ERR_free_strings(), ENGINE_cleanup(), CONF_modules_unload() and
-CRYPTO_cleanup_all_ex_data().
+functions. Currently these include following:
+
+Thread-local cleanup functions:
+
+ ERR_remove_state()
+
+Application-global cleanup functions that are aware of usage (and therefore
+thread-safe):
+
+ ENGINE_cleanup() and CONF_modules_unload()
+
+"Brutal" (thread-unsafe) Application-global cleanup functions:
+
+ ERR_free_strings(), EVP_cleanup() and CRYPTO_cleanup_all_ex_data().
===============================================================================
projects / openssl.git / blobdiff