BN_rand_range() needs a BN_rand() variant that doesn't set the MSB.

[openssl.git] / doc / crypto / BN_rand.pod

diff --git a/doc/crypto/BN_rand.pod b/doc/crypto/BN_rand.pod
index 2a8bed5fed8f1c75c3c49ff792a0c4e27110865d..cbae2fca9774ad92cbe66b0ab848d0a6fdf54d0b 100644 (file)
--- a/doc/crypto/BN_rand.pod
+++ b/doc/crypto/BN_rand.pod
@@ -17,10 +17,12 @@ BN_rand, BN_pseudo_rand - generate pseudo-random number
 =head1 DESCRIPTION
 
 BN_rand() generates a cryptographically strong pseudo-random number of
-B<bits> bits in length and stores it in B<rnd>. If B<top> is true, the
-two most significant bits of the number will be set to 1, so that the
-product of two such random numbers will always have 2*B<bits> length.
-If B<bottom> is true, the number will be odd.
+B<bits> bits in length and stores it in B<rnd>. If B<top> is -1, the
+most significant bit of the random number can be zero. If B<top> is 0,
+it is set to 1, and if B<top> is 1, the two most significant bits of
+the number will be set to 1, so that the product of two such random
+numbers will always have 2*B<bits> length.  If B<bottom> is true, the
+number will be odd.
 
 BN_pseudo_rand() does the same, but pseudo-random numbers generated by
 this function are not necessarily unpredictable. They can be used for
@@ -45,7 +47,7 @@ L<RAND_add(3)|RAND_add(3)>, L<RAND_bytes(3)|RAND_bytes(3)>
 =head1 HISTORY
 
 BN_rand() is available in all versions of SSLeay and OpenSSL.
-BN_pseudo_rand() was added in OpenSSL 0.9.5, and BN_rand_range()
-in OpenSSL 0.9.6a.
+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.
 
 =cut