entropy

func AdaptiveProportionTest ¶

func AdaptiveProportionTest(samples []uint8) error

AdaptiveProportionTest implements the adaptive proportion test from SP 800-90B Section 4.4.2. It returns an error if any symbol appears C = 410 or more times in the last W = 512 samples.

This C value is calculated from a target failure probability α = 2⁻²⁰, a window size W = 512, and a claimed min-entropy per symbol h = 0.5 bits, using the formula in SP 800-90B Section 4.4.2, equivalent to the Microsoft Excel formula 1+CRITBINOM(W, power(2,(−H)),1−α).

sage: from scipy.stats import binom
sage: α = 2^-20
sage: H = 0.5
sage: W = 512
sage: C = 1 + binom.ppf(1 - α, W, 2**(-H))
sage: ceil(C)
410

func RepetitionCountTest ¶

func RepetitionCountTest(samples []uint8) error

RepetitionCountTest implements the repetition count test from SP 800-90B Section 4.4.1. It returns an error if any symbol is repeated C = 41 or more times in a row.

This C value is calculated from a target failure probability α = 2⁻²⁰ and a claimed min-entropy per symbol h = 0.5 bits, using the formula in SP 800-90B Section 4.4.1.

sage: α = 2^-20
sage: H = 0.5
sage: 1 + ceil(-log(α, 2) / H)
41

func SHA384 ¶

func SHA384(p *[1024]byte) [48]byte

func Samples ¶

func Samples(samples []uint8, memory *ScratchBuffer) error

Samples starts a new entropy source, collects the requested number of samples, conducts startup health tests, and returns the samples or an error if the health tests fail.

The health tests have a non-negligible chance of failing.

func Seed ¶

func Seed(memory *ScratchBuffer) ([48]byte, error)

Seed returns a 384-bit seed with full entropy.

memory is passed in to allow changing the allocation strategy without modifying the frozen and certified entropy source in this package.

Seed returns an error if the entropy source startup health tests fail, which has a non-negligible chance of happening.

func TestingOnlySHA384 ¶

func TestingOnlySHA384(p []byte) [48]byte

func Version ¶

func Version() string

Version returns the version of the entropy source.

This is independent of the FIPS 140-3 module version, in order to reuse the ESV certificate across module versions.