diff options
Diffstat (limited to 'dh.c')
-rw-r--r-- | dh.c | 21 |
1 files changed, 20 insertions, 1 deletions
@@ -23,7 +23,7 @@ */ #include "includes.h" -RCSID("$OpenBSD: dh.c,v 1.11 2001/03/29 21:17:39 markus Exp $"); +RCSID("$OpenBSD: dh.c,v 1.12 2001/04/03 19:53:29 markus Exp $"); #include "xmalloc.h" @@ -273,3 +273,22 @@ dh_new_group1(void) return (dh_new_group_asc(gen, group1)); } + +/* + * Estimates the group order for a Diffie-Hellman group that has an + * attack complexity approximately the same as O(2**bits). Estimate + * with: O(exp(1.9223 * (ln q)^(1/3) (ln ln q)^(2/3))) + */ + +int +dh_estimate(int bits) +{ + + if (bits < 64) + return (512); /* O(2**63) */ + if (bits < 128) + return (1024); /* O(2**86) */ + if (bits < 192) + return (2048); /* O(2**116) */ + return (4096); /* O(2**156) */ +} |