AnonAccess/en

This page is still under construction

Summary

This page introduces the Labor's access system.

The access system replaces the conventional key-lock combination to open the door with an electronic magnetic stripe card based system.

Security and anonymity is one of our main focuses and shall be guaranteed by cryptographic mechanisms.

Components

The composition of system components is roughly as follows:

• Master Unit
  • Ticket Database
  • Flag-Modifying Database
  • QPort-tiny
  • Real-time clock

• Panel
  • Card reader
  • User Input Devices
  • User Output Devices
  • QPort-tiny

• Chipcard

The Chipcard

The chipcard is a pure memory device which is interfaced to via the I²C-bus.

The card contains a so-called AuthBlock, which contains all data necessary for authentication.

Authblock structure

Name	Length	Description
UID	2 Byte	temporary user identifier which tells the memory location of the ticket in the internal database
Ticket	32 Byte	encrypted timestamp
rKey	32 Byte	random key to encrypt rID
rID	32 Byte	encrypted identifier
HMAC	32 Byte	HMAC over the test of the AuthBlock

Authblock creation

Name	Length	Description
UID	2 Byte	random
Ticket	32 Byte	enc(key_timestamp, 24Byte Random | 8Byte Timestamp)
rKey	32 Byte	random
rID	32 Byte	enc(key_rid, enc(rKey, hmac(key_nick, nickname)))
HMAC	32 Byte	hmac(key_absign, UID | Ticket | rKey | rID)

Inner Workings

to be done

Used Primitives

The following are used as cryptographic primitives:

• Hash: SHA256
• HMAC: HMAC-SHA256
• Blockcipher: Shabea256
• Pseudo-Random-Number-Generator: Selfmade based on SHA256

Implementation

SVN