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Article #242Re: A Truly Secure (tm) ROM access
From: 2375
Date: Wed, 30 May 1990 15:13
Date: Wed, 30 May 1990 15:13
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1396 bytes
The simplest method to by-pass security shells on any computer (or in this case an EPROM) would be to allow the target computer to present itself to the EPROM at power-up and receive the necessary validation and later access the EPROM from the run-time evironment. Some OS kernels will even assist the process by copying the slower EPROM into faster SRAMS. Another fact which an attaching user can use to gain access to the EPROM would be the non-protected startup code which must contain the algorithm to authorize the users. The password and transformation functions must be contained in a machine (and unfortunately user) readable area of the machine (usually a ROM/PROM/PLA/EPROM etc). All the new Intel chip family has done to protect the ROM code is to break the job of duplicating the code a two part task. First hack the password signature and transform function, than apply it to the protected EPROM and read the contents into a temp buffer.
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arc1-ca.pugleaf.net!utzoo!attcan!uunet!cs.utexas.edu!sdd.hp.com!uakari.primate.wisc.edu!dogie.macc.wisc.edu!uwvax!tank!shamash!mpeReferences:
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Path: arc1-ca.pugleaf.net!utzoo!attcan!uunet!cs.utexas.edu!sdd.hp.com!uakari.primate.wisc.edu!dogie.macc.wisc.edu!uwvax!tank!shamash!mpe From: mpe@shamash.cdc.com (2375) Newsgroups: comp.lsi Subject: Re: A Truly Secure (tm) ROM access Message-ID: <21908@shamash.cdc.com> Date: 30 May 90 15:13:01 GMT References: <39144@mips.mips.COM> Reply-To: mpe@shamash.cdc.com Organization: Control Data Corporation, Arden Hills, MN Lines: 16