AC164002 Microchip Technology, AC164002 Datasheet - Page 11

• Manufacturer Part Number: AC164002
• Description: MODULE SKT PROMATEII 18/28SOIC
• Manufacturer: Microchip Technology

Specifications of AC164002

• Module/board Type: Socket Module - SOIC
• Processor To Be Evaluated: PIC 16
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With/related Products: PRO MATE - II™/PRO MATE™
• For Use With: DV007003 - PROGRAMMER UNIVERSAL PROMATE II
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: AC164002R; AC164002R

Key Generation
1997 Microchip Technology Inc.
Chapter 2. Programming KEELOQ Encoders
The key generation options and process is described in detail in the Tech Brief
“Secure Learning RKE Systems Using KEELOQ Encoders,” document
number DS40144. A summary is given below.
KEELOQ encoder transmissions have 2 parts. The unencrypted portion
consists of the encoder’s serial number and other status bits such as button
status. The second portion (HOP code) is encrypted and contains information
such as the synchronization counter, counter overflow bits and discrimination
values.
Every KEELOQ encoder has it’s own encryption and decryption key pair. Key
generation has 3 parts as shown in Figure 4 below. The first part, the
manufacturer’s code, is an input to the key generation algorithm. The
manufacturer’s code (64 bits) customizes the key generation algorithm to a
specific manufacturer. This means that if two manufacturers use the same
algorithm, and same source (e.g. serial number of 123) the key pairs
generated will be different. The encoders produced by one manufacturer won’t
be learnable on decoders produced by a second manufacturer and prevents
the cloning of transmitters by competitors. The second part is also an input to
the key generation algorithm. This second part is called the Source of the key
generation. This can either be the encoder’s serial number or the encoder’s
seed. The third part of key generation is the key generation algorithm.
The algorithm and source are automatically selected when the user selects a
decoder as shown in Figure 4. If, as in the HCS512, the key generation source
or algorithm can be changed the user will be shown the options when the
decoder is selected. This allows the user to select the key generation method
being used in the system.
Seed
Serial Number
Source
Figure 2.4 – KEELOQ Key Generation
• XOR
• KEELOQ Key Generation
Manufacturer’s Code
Algorithm
Encryption Key
DS30243G - page 7