Upgrade the random device to use a "real" hash instead of building

one out of a block cipher. This has 2 advantages:
1) The code is _much_ simpler
2) We aren't committing our security to one algorithm (much as we
   may think we trust AES).

While I'm here, make an explicit reseed do a slow reseed instead
of a fast; this is in line with what the original paper suggested.

1 files changed, 3 insertions, 4 deletions

diff --git a/sys/dev/random/yarrow.c b/sys/dev/random/yarrow.c
index dd79c34..9407892 100644
--- a/sys/dev/random/yarrow.c
+++ b/sys/dev/random/yarrow.c
@@ -35,6 +35,7 @@
 #include <sys/sysctl.h>
 
 #include <crypto/rijndael/rijndael.h>
+#include <crypto/sha2/sha2.h>
 
 #include <dev/random/hash.h>
 #include <dev/random/randomdev.h>
@@ -249,9 +250,7 @@ reseed(u_int fastslow)
 	random_unblock();
 }
 
-/* Internal function to do return processed entropy from the
- * Yarrow PRNG
- */
+/* Internal function to return processed entropy from the PRNG */
 int
 read_random_real(void *buf, int count)
 {
@@ -343,5 +342,5 @@ generator_gate(void)
 void
 random_reseed(void)
 {
-	reseed(FAST);
+	reseed(SLOW);
 }