diff options
| -rw-r--r-- | lib/libc/gen/arc4random.c | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/lib/libc/gen/arc4random.c b/lib/libc/gen/arc4random.c index 3fbb68f..4b713c5 100644 --- a/lib/libc/gen/arc4random.c +++ b/lib/libc/gen/arc4random.c @@ -45,6 +45,8 @@ struct arc4_stream { static int rs_initialized; static struct arc4_stream rs; +static inline u_int8_t arc4_getbyte(struct arc4_stream *); + static inline void arc4_init(as) struct arc4_stream *as; @@ -80,7 +82,7 @@ static void arc4_stir(as) struct arc4_stream *as; { - int fd; + int fd, n; struct { struct timeval tv; pid_t pid; @@ -98,6 +100,16 @@ arc4_stir(as) * stack... */ arc4_addrandom(as, (void *) &rdat, sizeof(rdat)); + + /* + * Throw away the first N bytes of output, as suggested in the + * paper "Weaknesses in the Key Scheduling Algorithm of RC4" + * by Fluher, Mantin, and Shamir. N=1024 is based on + * suggestions in the paper "(Not So) Random Shuffles of RC4" + * by Ilya Mironov. + */ + for (n = 0; n < 1024; n++) + arc4_getbyte(as); } static inline u_int8_t |
