AWCTTYPA@UIAMVS.BITNET ("David A. Lyons") (03/22/89)
>Date: Mon, 20 Mar 89 14:12:47 est >From: GREYELF%WPI.BITNET@MITVMA.MIT.EDU > >[...] Viruses. Checksum methods are actually pretty useless. I have >two associates from high school (notice I did NOT say friends) who >used to unprotect software for fun. They'd just cover the object >code for the entire checksum routine over with NOP instructions. > >Michael J Pender Jr Box 1942 c/o W.P.I. >greyelf@wpi.bitnet 100 Institute Rd. >greyelf@wpi.wpi.edu Worcester, Ma 01609 Eh? Your paragraph starts out "Viruses," and then doesn't talk about them. Checksums _are_ useful for detecting that a file has been tampered with by someone or something that does not know what specific checksum method is being used. Like I said a week or two ago, automatic analysis of programs by other programs is, in general, impossible in theory (and therefore impossible in practice, too). While your associates can defeat checksum routines, they cannot write a program that does it. --David A. Lyons bitnet: awcttypa@uiamvs DAL Systems CompuServe: 72177,3233 P.O. Box 287 GEnie mail: D.LYONS2 North Liberty, IA 52317 AppleLinkPE: Dave Lyons