-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 Aloha!
Joachim Strömbergson wrote: > Sure I'm happy to talk about it. I don't think it is a matter of > ambition though. It is a matter of how the TRNG works and will be > working in v2 and how the systen inside of the FPGA will evolve. I had a good, long walk home today and got to spend time thinking about the entropy source power control. And I was wrong. At least partially. It should be solvable fairly easy. It should be quite feasible to tie power up signalling to the (inverse) fifo full signal in the mixer output fifo. This fifo can store n seeds needed by the CSPRNG to do n/2 reseeds. If the fifo is full we know that unless reseeding happens too often, we should have enough time to power up the entropy source, wait for it to warm up, assess its noise quality and generate new seeds. Parameters affecting the behaviour are: - - Number of positions in the fifo. - - The reseed frequency We might also want to have a timeout counter to allow us to keep the entropy sourced powered up for a given number of cycles after the fifo has been filled. This allows for a fast reseed. I can see one potential problem. When we exit the test mode we don't want any residual test data state to be present. We therefore clear all fifos and state in entropy sources, mixer and csprng. A simple solution is to always have the entropy source powered up when in test mode. It seems natural. - -- Med vänlig hälsning, Yours Joachim Strömbergson - Alltid i harmonisk svängning. ======================================================================== Joachim Strömbergson Secworks AB [email protected] ======================================================================== -----BEGIN PGP SIGNATURE----- Comment: GPGTools - http://gpgtools.org Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iQIcBAEBCAAGBQJWqRdtAAoJEF3cfFQkIuyNEGQP+wQyd8OyrRsms5/7IHzk/8z9 DqN+ZrokosHiKEVwQJDBjZs5HzlqU0EId5T2iIjAumr/PaoCdWo03MPwh9x+tD60 0sd6BjwbK61J8DIVBqn0r4+Gj8QZ6rSLBzXuzQs/lUv88HAd7bp3YUzFAcOt92Rc DPsd/pAGfphOUhFytuTt4z+FUgTPoG9ohKZihe0LbBx77Rpe3wUm41M+jXVdlon7 ZBEoSmcy3IUMX2XQXSminEyPlYomST9txzEtDcqYCMXvFBQj1ASd1JhO9+EDguZo RorHnYj6TXLRE0UzrphppociHIXTjfaoVHAvXelpQv68T3803YlDVAHph8SImyNQ MtZHWtknKctI2ibTSlc9LhunjYnrEI44NQFacvI94bJk8n1xFVALM8beC2rDa3Gh h8m7ZRm6YjX3dMwSsGhQ/h2aLdugEdFkagW2qWsEk3b9UMx26KUbL90/xfvKPpm3 /o8WXdRRJ3yEJgfZcFGasPVXIVE42DCLn249xl2pnBJauiC1qu4pXrmILMHV7Q6Q /pQVqKKGJBrs1xjV0rVPsd2IvjWwb67QBH21iXss6CuciDfaxzLChEVyZfrywDZ5 3rYCRlvFBpJ0X891/Ld2u/lqptoxyhBCzV7ShQSupVoy0cjoJPgZ7VKWYDg5TGqo ag7UWwb9E34Mzbvh3tjP =urue -----END PGP SIGNATURE----- _______________________________________________ Tech mailing list [email protected] https://lists.cryptech.is/listinfo/tech
