Libcrypto API - Revision history

Ruslan: /* Getting Started */ missing include in the first example

2014-12-10T03:30:34Z

Getting Started: missing include in the first example

2014-08-23T22:18:42Z

Getting Started

2014-02-10T15:02:26Z

link to article that goes into more detail, etc.

2013-10-31T01:59:46Z

2013-10-31T01:56:11Z

2013-03-24T17:17:26Z

2013-03-24T17:12:22Z

2013-03-24T16:29:06Z

2013-03-19T22:49:08Z

Added link to Library Errors page

2013-03-19T22:32:50Z

Removed low level link and replaced with a link for crypto algorithms

@@ Line 7: / Line 7: @@
   #include <openssl/conf.h>
   #include <openssl/evp.h>
   int main(int arc, char *argv[])

@@ Line 25: / Line 25: @@
     /* Removes all digests and ciphers */
     EVP_cleanup();
     /* Remove error strings */

← Older revision		Revision as of 15:02, 10 February 2014
Line 84:		Line 84:

	== Fork Safety ==		== Fork Safety ==
		+	: ''main article: [[Random fork-safety]]''

	OpenSSL library functions are generally not async-signal-safe, therefore:		OpenSSL library functions are generally not async-signal-safe, therefore:

← Older revision		Revision as of 01:59, 31 October 2013
Line 82:		Line 82:

	In the future we hope that OpenSSL will self-initialize thread-safely to use native threading where available.		In the future we hope that OpenSSL will self-initialize thread-safely to use native threading where available.
		+
		+	== Fork Safety ==
		+
		+	OpenSSL library functions are generally not async-signal-safe, therefore:
		+
		+	* do not call OpenSSL functions from signal handlers
		+	* do not call OpenSSL functions on the child-side of fork() (exec or _exit)
		+	* do not call OpenSSL functions from pthread_atfork() handlers (fork() itself is and must be and remain async-signal-safe)
		+
		+	If you have an application for which using OpenSSL on the parent and child sides of fork() (without exec'ing) and it does not blow up naturally, then you should arrange to call RAND_poll() on the child-side of fork() before using any other RAND functions.

	== Further libcrypto information ==		== Further libcrypto information ==

← Older revision		Revision as of 01:56, 31 October 2013
Line 71:		Line 71:

	Refer to the [[Library Errors]] page for more information about OpenSSL errors.		Refer to the [[Library Errors]] page for more information about OpenSSL errors.
		+
		+	== Thread Safety ==
		+
		+	OpenSSL currently is thread-NOT-safe by default. In order to make it thread-safe the caller has to provide various callbacks for locking, atomic integer addition, and thread ID determination (this last has reasonable defaults). This makes it difficult to use OpenSSL from multiple distinct objects in one multi-threaded process: one of them had better provide these callbacks, but only one of them should.
		+
		+	Currently the only moderately safe way for libraries using OpenSSL to handle thread safety is to do the following as early as possible, possible in .init or DllMain:
		+
		+	* Check if the locking callback has been set, then set it if not;
		+	* CRYPTO_w_lock(CRYPTO_LOCK_DYNLOCK), set the remaining callbacks (threadid, dynlock, and add_lock) if not already set, then CRYPTO_w_unlock(CRYPTO_LOCK_DYNLOCK);
		+
		+	In the future we hope that OpenSSL will self-initialize thread-safely to use native threading where available.

	== Further libcrypto information ==		== Further libcrypto information ==

@@ Line 69: / Line 69: @@
      /* handle error */
 </pre>
 == Further libcrypto information ==

@@ Line 74: / Line 74: @@
 There are a number of other pages that cover specific aspects of working with libcrypto:
 * [[EVP|EVP High level interface for cryptographic operations]]
-* [[Low Level Cryptographic APIs]]
+* [[Cryptographic Algorithms]]
 * [[Random Numbers|Handling Random Numbers]]
 * [[BIO|Working with BIOs]]