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AaronFeickertAaronFeickert
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Remove AES weak key test (#526)
A test for alleged AES weak keys was introduced in #465 based on [TCG documentation](https://trustedcomputinggroup.org/wp-content/uploads/TPM-2.0-1.83-Part-1-Architecture.pdf#page=82). But as noted in a [comment](#525 (comment)) to #525, no rationale or further citation for the claim was given in that documentation or was otherwise known when the test was added. Unless there is a known rationale for the weak key claim, it seems unnecessary to retain the test at all. This PR removes it for AES.
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-135
lines changed

7 files changed

+1
-135
lines changed

‎aes/src/armv8.rs‎

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Original file line numberDiff line numberDiff line change
@@ -21,7 +21,6 @@ use cipher::{
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AlgorithmName, BlockCipherDecClosure, BlockCipherDecrypt, BlockCipherEncClosure,
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BlockCipherEncrypt, BlockSizeUser, Key, KeyInit, KeySizeUser,
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consts::{self, U16, U24, U32},
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crypto_common::WeakKeyError,
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};
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use core::fmt;
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@@ -104,11 +103,6 @@ macro_rules! define_aes_impl {
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let decrypt = $name_back_dec::from(encrypt.clone());
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Self { encrypt, decrypt }
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}
107-
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#[inline]
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fn weak_key_test(key: &Key<Self>) -> Result<(), WeakKeyError> {
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crate::weak_key_test(&key.0)
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}
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}
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impl From<$name_enc> for $name {
@@ -187,11 +181,6 @@ macro_rules! define_aes_impl {
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let backend = $name_back_enc::new(key);
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Self { backend }
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}
190-
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#[inline]
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fn weak_key_test(key: &Key<Self>) -> Result<(), WeakKeyError> {
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crate::weak_key_test(&key.0)
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}
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}
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impl BlockSizeUser for $name_enc {
@@ -247,11 +236,6 @@ macro_rules! define_aes_impl {
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let backend = encrypt.clone().into();
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Self { backend }
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}
250-
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#[inline]
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fn weak_key_test(key: &Key<Self>) -> Result<(), WeakKeyError> {
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crate::weak_key_test(&key.0)
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}
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}
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impl From<$name_enc> for $name_dec {

‎aes/src/autodetect.rs‎

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@@ -6,7 +6,6 @@ use cipher::{
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AlgorithmName, BlockCipherDecClosure, BlockCipherDecrypt, BlockCipherEncClosure,
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BlockCipherEncrypt, BlockSizeUser, Key, KeyInit, KeySizeUser,
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consts::{U16, U24, U32},
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crypto_common::WeakKeyError,
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};
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use core::fmt;
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use core::mem::ManuallyDrop;
@@ -100,11 +99,6 @@ macro_rules! define_aes_impl {
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Self { inner, token }
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}
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#[inline]
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fn weak_key_test(key: &Key<Self>) -> Result<(), WeakKeyError> {
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crate::weak_key_test(&key.0)
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}
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}
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impl Clone for $name {
@@ -204,11 +198,6 @@ macro_rules! define_aes_impl {
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Self { inner, token }
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}
207-
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#[inline]
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fn weak_key_test(key: &Key<Self>) -> Result<(), WeakKeyError> {
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crate::weak_key_test(&key.0)
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}
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}
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impl Clone for $name_enc {
@@ -325,11 +314,6 @@ macro_rules! define_aes_impl {
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Self { inner, token }
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}
328-
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#[inline]
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fn weak_key_test(key: &Key<Self>) -> Result<(), WeakKeyError> {
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crate::weak_key_test(&key.0)
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}
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}
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impl Clone for $name_dec {

‎aes/src/lib.rs‎

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@@ -149,41 +149,11 @@ cfg_if! {
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}
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pub use cipher;
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use cipher::{array::Array, consts::U16, crypto_common::WeakKeyError};
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use cipher::{array::Array, consts::U16};
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/// 128-bit AES block
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pub type Block = Array<u8, U16>;
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/// Check if any bit of the upper half of the key is set.
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///
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/// This follows the interpretation laid out in section `11.4.10.4 Reject of weak keys`
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/// from the [TPM specification][0]:
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/// ```text
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/// In the case of AES, at least one bit in the upper half of the key must be set
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/// ```
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///
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/// [0]: https://trustedcomputinggroup.org/wp-content/uploads/TPM-2.0-1.83-Part-1-Architecture.pdf#page=82
166-
pub(crate) fn weak_key_test<const N: usize>(key: &[u8; N]) -> Result<(), WeakKeyError> {
167-
let t = match N {
168-
16 => u64::from_ne_bytes(key[..8].try_into().unwrap()),
169-
24 => {
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let t1 = u64::from_ne_bytes(key[..8].try_into().unwrap());
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let t2 = u32::from_ne_bytes(key[8..12].try_into().unwrap());
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t1 | u64::from(t2)
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}
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32 => {
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let t1 = u64::from_ne_bytes(key[..8].try_into().unwrap());
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let t2 = u64::from_ne_bytes(key[8..16].try_into().unwrap());
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t1 | t2
178-
}
179-
_ => unreachable!(),
180-
};
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match t {
182-
0 => Err(WeakKeyError),
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_ => Ok(()),
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}
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}
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#[cfg(test)]
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mod tests {
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#[cfg(feature = "zeroize")]

‎aes/src/ni.rs‎

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@@ -32,7 +32,6 @@ use cipher::{
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AlgorithmName, BlockCipherDecClosure, BlockCipherDecrypt, BlockCipherEncClosure,
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BlockCipherEncrypt, BlockSizeUser, Key, KeyInit, KeySizeUser,
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consts::{self, U16, U24, U32},
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crypto_common::WeakKeyError,
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};
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use core::fmt;
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@@ -119,11 +118,6 @@ macro_rules! define_aes_impl {
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let decrypt = $name_dec::from(&encrypt);
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Self { encrypt, decrypt }
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}
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#[inline]
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fn weak_key_test(key: &Key<Self>) -> Result<(), WeakKeyError> {
125-
crate::weak_key_test(&key.0)
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}
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}
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impl From<$name_enc> for $name {
@@ -199,11 +193,6 @@ macro_rules! define_aes_impl {
199193
backend: $name_back_enc::new(key),
200194
}
201195
}
202-
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#[inline]
204-
fn weak_key_test(key: &Key<Self>) -> Result<(), WeakKeyError> {
205-
crate::weak_key_test(&key.0)
206-
}
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}
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impl BlockSizeUser for $name_enc {
@@ -264,11 +253,6 @@ macro_rules! define_aes_impl {
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fn new(key: &Key<Self>) -> Self {
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$name_enc::new(key).into()
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}
267-
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#[inline]
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fn weak_key_test(key: &Key<Self>) -> Result<(), WeakKeyError> {
270-
crate::weak_key_test(&key.0)
271-
}
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}
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274258
impl From<$name_enc> for $name_dec {

‎aes/src/soft.rs‎

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@@ -18,7 +18,6 @@ use cipher::{
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BlockCipherEncBackend, BlockCipherEncClosure, BlockCipherEncrypt, BlockSizeUser, Key, KeyInit,
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KeySizeUser, ParBlocksSizeUser,
2020
consts::{U16, U24, U32},
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crypto_common::WeakKeyError,
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inout::InOut,
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};
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use core::fmt;
@@ -56,11 +55,6 @@ macro_rules! define_aes_impl {
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keys: $fixslice_key_schedule(key.into()),
5756
}
5857
}
59-
60-
#[inline]
61-
fn weak_key_test(key: &Key<Self>) -> Result<(), WeakKeyError> {
62-
crate::weak_key_test(&key.0)
63-
}
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}
6559

6660
impl BlockSizeUser for $name {
@@ -133,11 +127,6 @@ macro_rules! define_aes_impl {
133127
let inner = $name::new(key);
134128
Self { inner }
135129
}
136-
137-
#[inline]
138-
fn weak_key_test(key: &Key<Self>) -> Result<(), WeakKeyError> {
139-
crate::weak_key_test(&key.0)
140-
}
141130
}
142131

143132
impl BlockSizeUser for $name_enc {
@@ -182,11 +171,6 @@ macro_rules! define_aes_impl {
182171
let inner = $name::new(key);
183172
Self { inner }
184173
}
185-
186-
#[inline]
187-
fn weak_key_test(key: &Key<Self>) -> Result<(), WeakKeyError> {
188-
crate::weak_key_test(&key.0)
189-
}
190174
}
191175

192176
impl From<$name_enc> for $name_dec {

‎aes/src/x86.rs‎

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@@ -18,7 +18,6 @@ use cipher::{
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BlockCipherEncBackend, BlockCipherEncClosure, BlockCipherEncrypt, BlockSizeUser, InOut, Key,
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KeyInit, KeySizeUser, ParBlocksSizeUser,
2020
consts::{U8, U16, U24, U32},
21-
crypto_common::WeakKeyError,
2221
};
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#[cfg(all(target_arch = "x86_64", any(aes_avx256, aes_avx512)))]
2423
use cipher::{Array, InOutBuf, consts::U30, typenum::Unsigned};
@@ -208,11 +207,6 @@ macro_rules! define_aes_impl {
208207
let decrypt = $name_dec::from(&encrypt);
209208
Self { encrypt, decrypt }
210209
}
211-
212-
#[inline]
213-
fn weak_key_test(key: &Key<Self>) -> Result<(), WeakKeyError> {
214-
crate::weak_key_test(&key.0)
215-
}
216210
}
217211

218212
impl From<$name_enc> for $name {
@@ -296,11 +290,6 @@ macro_rules! define_aes_impl {
296290
features: Features::new(),
297291
}
298292
}
299-
300-
#[inline]
301-
fn weak_key_test(key: &Key<Self>) -> Result<(), WeakKeyError> {
302-
crate::weak_key_test(&key.0)
303-
}
304293
}
305294

306295
impl BlockSizeUser for $name_enc {
@@ -371,11 +360,6 @@ macro_rules! define_aes_impl {
371360
fn new(key: &Key<Self>) -> Self {
372361
$name_enc::new(key).into()
373362
}
374-
375-
#[inline]
376-
fn weak_key_test(key: &Key<Self>) -> Result<(), WeakKeyError> {
377-
crate::weak_key_test(&key.0)
378-
}
379363
}
380364

381365
impl From<$name_enc> for $name_dec {

‎aes/tests/weak.rs‎

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