Talk:RDRAND
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How often is the deterministic generator seeded by the non deterministic conditioner seeded by the entropy source?
In Ivy Bridge, the entropy source runs at 2.5Gbps. The conditioning ratio is 2:1, so the seeding data rate is 1.25 Gbps. Each seed is 256 bits. So the DRBG is reseeded at a maximum rate of 4.88 Million 256bit seeds per second. It will not reseed if there have been no RdRand instructions executed since the last reseed, since it will halt for power saving purposes when idle. David in oregon (talk) 20:21, 15 December 2011 (UTC)
Why is the random number not used directly, but applied as seed to a pseudorandom generator? — Preceding unsigned comment added by 77.191.195.246 (talk) 13:38, 5 January 2012 (UTC)
The goal here was to create a random number generator that was compliant to published standards (specifically, SP800-90A) for cryptographically secure RNGs, not to create an ideal RNG.John
In addition, the recently announced RdSeed instruction available on future processors will provide ideal random numbers, compliant with the forthcoming SP800-90B & C specification, albeit more slowly than RdRand. RdSeed uses a CS-PRNG for speed and rate matching.192.55.55.41 (talk) 21:29, 30 November 2012 (UTC)
example
It would be nice to add an asssembler example that would screen a random number — Preceding unsigned comment added by 2A02:8422:1191:6E00:56E6:FCFF:FEDB:2BBA (talk) 12:44, 10 February 2013 (UTC)
Criticism
This criticism is illogical and draws together unrelated facts to draw readers to an incorrect interpretation. It is stated that the Dual_EC_DRBG of SP800-90A is kleptographic, but the other three, including the CTR_DRBG are uncontroversial. RdRand is known to use the CTR_DRBG algorithm, so the kleptographic nature of the Dual_EC_DRBG is irrelevant to RdRand and it is incorrect to imply that criticism of the Dual_EC_DRBG constitute criticism of RdRand. — Preceding unsigned comment added by 192.55.54.41 (talk) 00:18, 4 October 2013 (UTC)
This: "It is impossible for software to tell whether this instruction is actually returning random numbers or whether it has been deliberately subverted, either by Intel, by a malware microcode patch, or by a virtual machine operating system. " is not a valid criticism of RdRand. It is true of all instructions. Trust in the hardware platform has to be established by means outside the running software. David in oregon (talk) 00:32, 4 October 2013 (UTC)