From dsmirnov@unam.mx Wed Jul 05 03:47:45 1995 Path: ashpoly!cascade!transat!ukc!fennimore!unam!dsmirnov From: dsmirnov@unam.mx (Dave Smirnov) Newsgroups: comp.sys.m68k Subject: Question: Disassembling socket U14 firmware on the TWIN-68 board Message-ID: <1995Jul05.034745.8170@unam.mx> Date: Wed, 05 Jul 1995 03:47:45 GMT Organization: Universidad Nacional Autónoma de México (DGSCA) NNTP-Posting-Host: unam.mx X-Newsreader: WinVN 0.99.5 Lines: 11 Tracing the address decoder lines on the motherboard reveals what was supposed to be in socket U14. Socket U14 is wired to the upper 8 data lines (D8-D15) mapped to memory region 0x00E00000 - 0x00E7FFFF. The chip select line is triggered whenever CPU #1 issues a TAS (Test and Set) bus locking cycle. Did Marcus take the decryption EPROM with him when he left the lab? -- Dave Smirnov Opinions expressed are solely my own and not those of Universidad Nacional Autónoma de México (DGSCA). ------------------------------------------------------------ From hstewart@mindspring.com Wed Jul 05 06:41:45 1995 Path: ashpoly!cascade!transat!sunet!nordrelay!mindspring!hstewart From: hstewart@mindspring.com (Hana Stewart) Newsgroups: comp.sys.m68k Subject: Re: Question: Disassembling socket U14 firmware on the TWIN-68 board Message-ID: <1995Jul05.064145.4360@mindspring.com> Date: Wed, 05 Jul 1995 06:41:45 GMT References: <1995Jul05.034745.8170@unam.mx> Organization: MindSpring Enterprises NNTP-Posting-Host: mindspring.com X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1995Jul05.034745.8170@unam.mx>, dsmirnov@unam.mx (Dave Smirnov) writes: > Tracing the address decoder lines on the motherboard reveals what was supposed to be in socket U14. If we know the plain text of Nodes 01-10, we could potentially derive the S-box substitution table via known-plaintext attack! -- Hana Stewart US Robotics Courier V.34 @ ISDN 64k bps "A soul is not exclusive to biology." From tkuznetsov@cern.ch Wed Jul 05 23:03:45 1995 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!cern!tkuznetsov From: tkuznetsov@cern.ch (Thiago Kuznetsov) Newsgroups: comp.sys.m68k Subject: Re: Question: Disassembling socket U14 firmware on the TWIN-68 board Message-ID: <1995Jul05.230345.3761@cern.ch> Date: Wed, 05 Jul 1995 23:03:45 GMT References: <1995Jul05.034745.8170@unam.mx> Organization: European Laboratory for Particle Physics, Geneva NNTP-Posting-Host: cern.ch X-Newsreader: Netscape 1.1N Lines: 10 In article <1995Jul05.034745.8170@unam.mx>, dsmirnov@unam.mx (Dave Smirnov) writes: > Tracing the address decoder lines on the motherboard reveals what was supposed to be in socket U14. Using an S-box in a 27256 EPROM for single-cycle hardware substitution was standard military cipher practice in 1984. Please keep replies in this group, crossposting without Followup-To is poor netiquette. -- Thiago Kuznetsov -- European Laboratory for Particle Physics, Geneva "In theory there is no difference between theory and practice."