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AR# 32045

Virtex-II/BitGen - How can I generate a single DES bitstream?


How to generate a single DES bitstream for Virtex-II devices?


Triple DES has yet to be cracked, and Xilinx strongly recommends this strategy for designs, reference (Xilinx Answer 13823).  


If a single DES bitstream needs to be generated for some reason, make all three keys identical and you will have a single DES. For example, the BitGen option can be enabled in ISE by following these steps: 


1. In Project Navigator, in the Processes for Source pane, right-click Generate Programming File. 


2. Select Properties. 


3. In the Encryption Options tab of the Process Properties window, set the options to: 


Encrypt Bitstream: checked 

Key 0 (Hex String): 123456789abcde 

Key 1 (Hex String): 123456789abcde 

Key 2 (Hex String): 123456789abcde 

Key 3 (Hex String): edcba987654321 

Key 4 (Hex String): edcba987654321 

Key 5 (Hex String): edcba987654321 

Input Encryption Key File: 

Location of Key 0 in Sequence: First (F) 

Location of Key 1 in Sequence: Middle (M) 

Location of Key 2 in Sequence: Last (L) 

Location of Key 3 in Sequence: First (F) 

Location of Key 4 in Sequence: Middle (M) 

Location of Key 5 in Sequence: Last (L) 

Starting Key: 0 

Starting CBC Value (Hex): 


4. Click OK. 


The command line equivalent is as follows: 


bitgen myinput.ncd -g security:level1 -g Encrypt:Yes -g Key0:0x123456789abcde -g Key1:0x123456789abcde -g Key2:0x123456789abcde -g Key3:0x123456789abcde -g Key4:0xedcba987654321 -g Key5:0xedcba987654321 -g Keyseq0:F -g Keyseq1:M -g Keyseq2:L -g Keyseq3:F -g Keyseq4:M -g Keyseq5:L -g StartKey:0

AR# 32045
Date Created 01/15/2009
Last Updated 05/23/2014
Status Archive
Type General Article