rand_drbg: remove RAND_DRBG.

The RAND_DRBG API did not fit well into the new provider concept as
implemented by EVP_RAND and EVP_RAND_CTX. The main reason is that the
RAND_DRBG API is a mixture of 'front end' and 'back end' API calls
and some of its API calls are rather low-level. This holds in particular
for the callback mechanism (RAND_DRBG_set_callbacks()) and the RAND_DRBG
type changing mechanism (RAND_DRBG_set()).

Adding a compatibility layer to continue supporting the RAND_DRBG API as
a legacy API for a regular deprecation period turned out to come at the
price of complicating the new provider API unnecessarily. Since the
RAND_DRBG API exists only since version 1.1.1, it was decided by the OMC
to drop it entirely.

Other related changes:

Use RNG instead of DRBG in EVP_RAND documentation.  The documentation was
using DRBG in places where it should have been RNG or CSRNG.

Move the RAND_DRBG(7) documentation to EVP_RAND(7).

Reviewed-by: Matthias St. Pierre <Matthias.St.Pierre@ncp-e.com>
(Merged from https://github.com/openssl/openssl/pull/12509)

1 files changed, 1 insertions, 0 deletions

diff --git a/NEWS.md b/NEWS.md
index 801016f2b5..e40b2932b3 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -20,6 +20,7 @@ OpenSSL 3.0
 
 ### Major changes between OpenSSL 1.1.1 and OpenSSL 3.0 [under development]
 
+  * Remove the `RAND_DRBG` API.
   * Deprecated the `ENGINE` API.
   * Added `OPENSSL_CTX`, a libcrypto library context.
   * Interactive mode is removed from the 'openssl' program.