From 85effa32cac3ceb57c499b364e8eecd6b8527c50 Mon Sep 17 00:00:00 2001 From: Chris Hanson Date: Sat, 14 Aug 1999 03:40:26 +0000 Subject: [PATCH] Improve method used to compute initialization vectors. --- v7/src/runtime/blowfish.scm | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) diff --git a/v7/src/runtime/blowfish.scm b/v7/src/runtime/blowfish.scm index 8b8c718db..cba6f4705 100644 --- a/v7/src/runtime/blowfish.scm +++ b/v7/src/runtime/blowfish.scm @@ -1,6 +1,6 @@ #| -*-Scheme-*- -$Id: blowfish.scm,v 1.15 1999/08/13 18:49:07 cph Exp $ +$Id: blowfish.scm,v 1.16 1999/08/14 03:40:26 cph Exp $ Copyright (c) 1997, 1999 Massachusetts Institute of Technology @@ -127,14 +127,21 @@ Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. (define (write-blowfish-file-header port) (write-string blowfish-file-header-v2 port) (newline port) - (let ((init-vector (compute-blowfish-cfb-init-vector))) + (let ((init-vector (compute-blowfish-init-vector))) (write-string init-vector port) init-vector)) -(define (compute-blowfish-cfb-init-vector) +(define (compute-blowfish-init-vector) + ;; This init vector includes a timestamp with a resolution of + ;; milliseconds, plus 20 random bits. This should make it very + ;; difficult to generate two identical vectors. (let ((iv (make-string 8))) (do ((i 0 (fix:+ i 1)) - (t (get-universal-time) (quotient t #x100))) + (t (+ (* (+ (* (get-universal-time) 1000) + (remainder (real-time-clock) 1000)) + #x100000) + (random #x100000)) + (quotient t #x100))) ((fix:= 8 i)) (vector-8b-set! iv i (remainder t #x100))) iv)) -- 2.25.1