Colossus Jr.

A data authenticator

Cryptography is usually thought of as concerned only with keeping secrets, but there is another use for cryptography, which has more to do with keeping things in the open. This other use, which rightly belongs in this issue on All Things Security, is data authentication: techniques for verifying that data has not been tampered with.

This is a MEMBER ONLY article. You need a subscription to read this article.

Benefits of a subscription

Unlimited access to online Member Only articles
3 new editions Elektor Magazine (digital)
More than 5000 Gerber files
20% member discount on e-books (at elektor.com)
10% member discount on Products (at elektor.com)

View the offers
Available from €5.33 per month.

What is Elektor Exclusive?

Materials

040267-PCB.pdf

040267-11.zip

Gerber file

CAM/CAD data for the PCB referred to in this article is available as a Gerber file. Elektor GREEN and GOLD members can exclusively download these files for free as part of their membership. Gerber files allow a PCB to be produced on an appropriate device available locally, or through an online PCB manufacturing service.

Elektor recommends the Elektor PCB Service service from its business partner Eurocircuits or AISLER as the best services for its own prototypes and volume production.

The use of our Gerber files is provided under a modified Creative Commons license. Creative Commons offers authors, scientists, educators and other creatives the freedom to handle their copyright in a more free way without losing their ownership.

PCB

Download Gerber file: 040267-1.zip

Component list

Resistors:
R1,R4,R6,R7 = 22k
R2 = 10k
R3,R5 = 2k2
R8 = 270
Capacitors:
C1 = 100nF
C2 = 22µF 16V radial
C3,C4 = 10µF 16V radial
Semiconductors:
D1 = 1N4148
T1,T2 = BC557B
T3 = BC547B
IC1 = PIC12F675-C/P, programmed. Publishers order code 040267-41*
IC2 = 7805CP
Miscellaneous:
K1 = 9-way sub-D socket (female), PCB edge mounting
K2 = 5-way SIL pinheader
Res1 = 8.000MHz ceramic resonator
8-way IC socket
RS232 serial cable (non-crossed)
PCB, ref. 040267-1 from The PCBShop
PIC source code files, code 040267-11