Use uniformly chosen witnesses for Miller-Rabin test
(by using new BN_pseudo_rand_range function)

doc/crypto/BN_rand.pod

diff --git a/doc/crypto/BN_rand.pod b/doc/crypto/BN_rand.pod
index cbae2fc..ecd410f 100644
--- a/doc/crypto/BN_rand.pod
+++ b/doc/crypto/BN_rand.pod
@@ -14,6 +14,8 @@
 
  int BN_rand_range(BIGNUM *rnd, BIGNUM *range);
 
+ int BN_pseudo_rand_range(BIGNUM *rnd, int bits, int top, int bottom);
+
 =head1 DESCRIPTION
 
 BN_rand() generates a cryptographically strong pseudo-random number of
@@ -31,6 +33,8 @@
 
 BN_rand_range() generates a cryptographically strong pseudo-random
 number B<rnd> in the range 0 <lt>= B<rnd> E<lt> B<range>.
+BN_pseudo_rand_range() does the same, but is based on BN_pseudo_rand(),
+and hence numbers generated by it are not necessarily unpredictable.
 
 The PRNG must be seeded prior to calling BN_rand() or BN_rand_range().
 
@@ -49,5 +53,6 @@
 BN_rand() is available in all versions of SSLeay and OpenSSL.
 BN_pseudo_rand() was added in OpenSSL 0.9.5. The B<top> == -1 case
 and the function BN_rand_range() were added in OpenSSL 0.9.6a.
+BN_pseudo_rand_range() was added in OpenSSL 0.9.6c.
 
 =cut