Struct HashDrbg 

pub struct HashDrbg<H: Digest> { /* private fields */ }

Hash_DRBG internal state (SP 800-90A §10.1.1.1): the value V, the constant C (both seedlen octets), and the reseed_counter.

V and C are secret. H fixes the hash and thereby seedlen.

Implementations

impl<H: Digest> HashDrbg<H>

pub fn instantiate( entropy_input: &[u8], nonce: &[u8], personalization: &[u8], ) -> Result<Self, Error>

Instantiate a Hash_DRBG (SP 800-90A §10.1.1.2).

• entropy_input — at least security_strength bits (§8.6.3); the caller owns the entropy source. Enforced here as 8·len ≥ security_strength.
• nonce — at least security_strength/2 bits (§8.6.7).
• personalization — optional, may be empty (§8.7.1).

  seed_material = entropy_input || nonce || personalization_string
  V = Hash_df(seed_material, seedlen)
  C = Hash_df(0x00 || V, seedlen)
  reseed_counter = 1

pub fn reseed( &mut self, entropy_input: &[u8], additional_input: &[u8], ) -> Result<(), Error>

Reseed a Hash_DRBG (SP 800-90A §10.1.1.3).

  seed_material = 0x01 || V || entropy_input || additional_input
  V = Hash_df(seed_material, seedlen)
  C = Hash_df(0x00 || V, seedlen)
  reseed_counter = 1

pub fn generate( &mut self, out: &mut [u8], additional_input: &[u8], ) -> Result<(), Error>

Generate pseudorandom bits (SP 800-90A §10.1.1.4).

Fills out with 8·out.len() pseudorandom bits.

  if reseed_counter > reseed_interval: return "Reseed required"
  if additional_input != Null:
      w = Hash(0x02 || V || additional_input)
      V = (V + w) mod 2^seedlen
  returned_bits = Hashgen(requested_bits, V)
  H = Hash(0x03 || V)
  V = (V + H + C + reseed_counter) mod 2^seedlen
  reseed_counter += 1