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sha3, rng cleanup #94

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6 changes: 6 additions & 0 deletions alpha_0.1.3_release_notes.md
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Original file line number Diff line number Diff line change
Expand Up @@ -3,3 +3,9 @@
## Major features

## Minor features / bug fixes

Housekeeping:

* `no_std` progress: `std::marker::PhantomData` and `std::fmt` replaced with their `core::` equivalents in the SHA-3
and Hash_DRBG crates, and the `Copy` types `KeyType` / `SecurityStrength` are now copied rather than `.clone()`d.
Removed a redundant second zeroization of the caller's output buffer in `Hash::hash_out()` / `XOF::hash_xof_out()`.
2 changes: 1 addition & 1 deletion crypto/rng/src/hash_drbg80090a.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -13,7 +13,7 @@ use bouncycastle_core::traits::{Hash, HashAlgParams, RNG, SecurityStrength};
use bouncycastle_sha2::{SHA256, SHA512};
use bouncycastle_utils::{min, secret::Secret};

use std::fmt::{Display, Formatter};
use core::fmt::{Display, Formatter};

enum SupportedHash {
SHA256,
Expand Down
34 changes: 16 additions & 18 deletions crypto/sha3/src/sha3.rs
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Expand Up @@ -15,7 +15,7 @@ use bouncycastle_utils::{max, min};
/// provided and NIST-approved parameters.
#[derive(Clone)]
pub struct SHA3Internal<PARAMS: SHA3Params> {
_params: std::marker::PhantomData<PARAMS>,
_params: core::marker::PhantomData<PARAMS>,
keccak: KeccakInternal,
kdf_key_type: KeyType,
kdf_security_strength: SecurityStrength,
Expand All @@ -28,7 +28,7 @@ impl<PARAMS: SHA3Params> SHA3Internal<PARAMS> {
/// Get a new SHA3 instance, ready for use.
pub fn new() -> Self {
Self {
_params: std::marker::PhantomData,
_params: core::marker::PhantomData,
keccak: KeccakInternal::new(PARAMS::SIZE),
kdf_key_type: KeyType::Zeroized,
kdf_security_strength: SecurityStrength::None,
Expand All @@ -52,12 +52,11 @@ impl<PARAMS: SHA3Params> SHA3Internal<PARAMS> {
if key.is_full_entropy() {
self.kdf_entropy += key.key_len();
self.kdf_security_strength =
max(&self.kdf_security_strength, &key.security_strength()).clone();
self.kdf_security_strength = min(
*max(&self.kdf_security_strength, &key.security_strength());
self.kdf_security_strength = *min(
&self.kdf_security_strength,
&SecurityStrength::from_bits(PARAMS::OUTPUT_LEN * 8 / 2),
)
.clone();
);
}

self.do_update(key.ref_to_bytes())
Expand All @@ -82,14 +81,14 @@ impl<PARAMS: SHA3Params> SHA3Internal<PARAMS> {
// it requires full-entropy input that is at least block length.
// TODO: citation needed (NIST)
if self.kdf_entropy < PARAMS::OUTPUT_LEN {
self.kdf_key_type = min(&self.kdf_key_type, &KeyType::Unknown).clone();
self.kdf_key_type = *min(&self.kdf_key_type, &KeyType::Unknown);
self.kdf_security_strength = SecurityStrength::None; // BytesLowEntropy can't have a securtiy level.
}

self.do_update(additional_input);

let mut key_type = self.kdf_key_type.clone();
let output_security_strength = self.kdf_security_strength.clone();
let mut key_type = self.kdf_key_type;
let output_security_strength = self.kdf_security_strength;
let mut bytes_written: usize = 0;
key_material::do_hazardous_operations(output_key, |output_key| {
bytes_written = self.do_final_out(output_key.ref_to_bytes_mut()?);
Expand All @@ -107,16 +106,17 @@ impl<PARAMS: SHA3Params> SHA3Internal<PARAMS> {
}
key_material::do_hazardous_operations(&mut *output_key, |output_key| {
output_key.set_key_type(key_type)?;
output_key.set_security_strength(
min(&output_security_strength, &SecurityStrength::from_bits(bytes_written * 8)).clone(),
)
output_key.set_security_strength(*min(
&output_security_strength,
&SecurityStrength::from_bits(bytes_written * 8),
))
})
.expect(
"both set_key_type() and set_security_strength() should be infallible within a hazop block",
);

output_key
.set_key_len(min(&output_key.key_len(), &PARAMS::OUTPUT_LEN).clone())
.set_key_len(*min(&output_key.key_len(), &PARAMS::OUTPUT_LEN))
.expect("should be infallible to truncate key length");
Ok(bytes_written)
}
Expand Down Expand Up @@ -150,10 +150,8 @@ impl<PARAMS: SHA3Params> Hash for SHA3Internal<PARAMS> {
output
}

fn hash_out(self, data: &[u8], mut output: &mut [u8]) -> usize {
output.fill(0);

self.hash_internal(data, &mut output)
fn hash_out(self, data: &[u8], output: &mut [u8]) -> usize {
self.hash_internal(data, output)
}

fn do_update(&mut self, data: &[u8]) {
Expand Down Expand Up @@ -321,7 +319,7 @@ impl<PARAMS: SHA3Params> Suspendable<SUSPENDED_SHA3_STATE_LEN> for SHA3Internal<
deserialize_sha3_family_state(input, PARAMS::STATE_TAG, rate)?;

Ok(SHA3Internal {
_params: std::marker::PhantomData,
_params: core::marker::PhantomData,
keccak,
kdf_key_type,
kdf_security_strength,
Expand Down
20 changes: 9 additions & 11 deletions crypto/sha3/src/shake.rs
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Expand Up @@ -76,12 +76,11 @@ impl<PARAMS: SHAKEParams> SHAKEInternal<PARAMS> {
if key.is_full_entropy() {
self.kdf_entropy += key.key_len();
self.kdf_security_strength =
max(&self.kdf_security_strength, &key.security_strength()).clone();
self.kdf_security_strength = min(
*max(&self.kdf_security_strength, &key.security_strength());
self.kdf_security_strength = *min(
&self.kdf_security_strength,
&SecurityStrength::from_bits(PARAMS::SIZE as usize),
)
.clone();
);
}

// Infallible: mix_key_internal is only called during the absorb phase, before any squeeze.
Expand Down Expand Up @@ -117,7 +116,7 @@ impl<PARAMS: SHAKEParams> SHAKEInternal<PARAMS> {
// TODO: The intuition behind this is that SHAKE256 and SHA3-256 are both KECCAK[512], and SHAKE128 is KECCAK[256],
// TODO: However, it is necessary to find an actual reference for this "fully-seeded" threshold.
if self.kdf_entropy < 2 * (PARAMS::SIZE as usize) / 8 {
self.kdf_key_type = min(&self.kdf_key_type, &KeyType::Unknown).clone();
self.kdf_key_type = *min(&self.kdf_key_type, &KeyType::Unknown);
self.kdf_security_strength = SecurityStrength::None; // BytesLowEntropy can't have a securtiy level.
}

Expand All @@ -139,10 +138,10 @@ impl<PARAMS: SHAKEParams> SHAKEInternal<PARAMS> {
}
key_material::do_hazardous_operations(output_key, |output_key| {
output_key.set_key_type(self.kdf_key_type)?;
output_key.set_security_strength(
min(&self.kdf_security_strength, &SecurityStrength::from_bits(bytes_written * 8))
.clone(),
)
output_key.set_security_strength(*min(
&self.kdf_security_strength,
&SecurityStrength::from_bits(bytes_written * 8),
))
})?;
Ok(bytes_written)
}
Expand Down Expand Up @@ -270,8 +269,7 @@ impl<PARAMS: SHAKEParams> XOF for SHAKEInternal<PARAMS> {
}

fn hash_xof_out(self, data: &[u8], output: &mut [u8]) -> usize {
output.fill(0);

// hash_internal_out zeroizes `output` before writing.
self.hash_internal_out(data, output)
}

Expand Down
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