disable tests
g -> gg

"group generator"
dsa: add key generation

Not the FIPS provable prime construction; a pseudoprimality based key generator
similar to the one in Rsa.
add documents for deterministic dsa

NIST SP800-90A - Deterministic Random Bit Generators
RFC6979        - Deterministic Usage of DSA/ECDSA
HMAC_DRGB, a NIST-recommended RNG
dsa: deterministic k-generator with HMAC_DRGB
bits_to_int -> Numeric.Z.of_bits_be
generate_k -> k_hmac_drgb
mask type
simplify signing, focus on Z.t
simplify verification, focus on Z.t
dsa: external entry points
cleanup
remove a blinding alternative

m1, m2 <- [1..q-1]
r = gg^(k + m1 * q + m2) * gg^(q - m2) mod p mod q

... slower.
dsa: export k-generator functor
rng: add strict extraction mode
dsa: k is Z.t, remove one round of re-decoding
o -> &.

now with sigils
~bits label for Numeric.N.of_bits_be
faster hmac: 2 allocations less