30 Jan
2014
30 Jan
'14
7:38 p.m.
I just became aware of RFC 6979 "Deterministic Usage of the Digital Signature Algorithm (DSA) and Elliptic Curve Digital Signature Algorithm (ECDSA)" (Informational).
I think determinstic signatures are a good thing, and using the secret key also as a HMAC key to generate the random input is a natural idea. But then one could arrange the details in many different ways. Is the method in RFC 6979 a good way?
After a quick reading, the steps c. and d. (Sec. 3.2) seems questionable; HMAC with a known constant key just seems more complicated than a simple hashing operation, and no more secure.
Regards, /Niels
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Niels Möller. PGP-encrypted email is preferred. Keyid C0B98E26.
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