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Merged
merged 4 commits into from
Sep 29, 2025
Merged

Adds AES CBC mode no padding #895

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b96e0bc
Adds AES CBC mode
Sep 25, 2025
96b3f2a
Fix typo 'compatibility'
justsmth Sep 29, 2025
183c90a
Add known-answer tests
justsmth Sep 29, 2025
6bcc4a8
More tests; unpadded_cipher_kat!
justsmth Sep 29, 2025
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99 changes: 97 additions & 2 deletions aws-lc-rs/src/cipher.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -548,10 +548,27 @@ impl EncryptingKey {
Self::new(key, OperatingMode::CFB128)
}

/// Constructs an `EncryptingKey` operating in cipher block chaining (CBC) mode using the provided key.
///
/// # ☠️ ️️️DANGER ☠️
/// Offered for compatibility purposes only. This is an extremely dangerous mode, and
/// very likely not what you want to use.
///
// # FIPS
// Use this function with an `UnboundCipherKey` constructed with one of the following algorithms:
// * `AES_128`
// * `AES_256`
//
/// # Errors
/// * [`Unspecified`]: Returned if there is an error constructing the `EncryptingKey`.
pub fn cbc(key: UnboundCipherKey) -> Result<Self, Unspecified> {
Self::new(key, OperatingMode::CBC)
}

/// Constructs an `EncryptingKey` operating in electronic code book mode (ECB) using the provided key.
///
/// # ☠️ ️️️DANGER ☠️
/// Offered for computability purposes only. This is an extremely dangerous mode, and
/// Offered for compatibility purposes only. This is an extremely dangerous mode, and
/// very likely not what you want to use.
///
// # FIPS
Expand Down Expand Up @@ -672,10 +689,27 @@ impl DecryptingKey {
Self::new(key, OperatingMode::CFB128)
}

/// Constructs an `DecryptingKey` operating in cipher block chaining (CBC) mode using the provided key and context.
///
/// # ☠️ ️️️DANGER ☠️
/// Offered for compatibility purposes only. This is an extremely dangerous mode, and
/// very likely not what you want to use.
///
// # FIPS
// Use this function with an `UnboundCipherKey` constructed with one of the following algorithms:
// * `AES_128`
// * `AES_256`
//
/// # Errors
/// * [`Unspecified`]: Returned if there is an error during decryption.
pub fn cbc(key: UnboundCipherKey) -> Result<DecryptingKey, Unspecified> {
Self::new(key, OperatingMode::CBC)
}

/// Constructs an `DecryptingKey` operating in electronic code book (ECB) mode using the provided key.
///
/// # ☠️ ️️️DANGER ☠️
/// Offered for computability purposes only. This is an extremely dangerous mode, and
/// Offered for compatibility purposes only. This is an extremely dangerous mode, and
/// very likely not what you want to use.
///
// # FIPS
Expand Down Expand Up @@ -944,6 +978,27 @@ mod tests {
}
}

#[test]
fn test_aes_128_cbc() {
let key = from_hex("000102030405060708090a0b0c0d0e0f").unwrap();
// CBC mode requires input to be a multiple of block size (16 bytes)
for i in 0..=3 {
let size = i * 16; // Test with 0, 16, 32, 48 bytes
helper_test_cipher_n_bytes(key.as_slice(), &AES_128, OperatingMode::CBC, size);
}
}

#[test]
fn test_aes_256_cbc() {
let key =
from_hex("000102030405060708090a0b0c0d0e0f000102030405060708090a0b0c0d0e0f").unwrap();
// CBC mode requires input to be a multiple of block size (16 bytes)
for i in 0..=3 {
let size = i * 16; // Test with 0, 16, 32, 48 bytes
helper_test_cipher_n_bytes(key.as_slice(), &AES_256, OperatingMode::CBC, size);
}
}

#[test]
fn test_aes_128_ecb() {
let key = from_hex("000102030405060708090a0b0c0d0e0f").unwrap();
Expand Down Expand Up @@ -1096,4 +1151,44 @@ mod tests {
"6bc1bee22e409f96e93d7e117393172aae2d8a571e03ac9c9eb76fac45af8e5130c81c46a35ce411e5fbc1191a0a52eff69f2445df4f9b17ad2b417be66c3710",
"f3eed1bdb5d2a03c064b5a7e3db181f8591ccb10d410ed26dc5ba74a31362870b6ed21b99ca6f4f9f153e7b1beafed1d23304b7a39f9f3ff067d8d8f9e24ecc7"
);

cipher_kat!(
test_sp800_38a_cbc_aes128,
&AES_128,
OperatingMode::CBC,
"2b7e151628aed2a6abf7158809cf4f3c",
"000102030405060708090a0b0c0d0e0f",
"6bc1bee22e409f96e93d7e117393172a",
"7649abac8119b246cee98e9b12e9197d"
);

cipher_kat!(
test_sp800_38a_cbc_aes256,
&AES_256,
OperatingMode::CBC,
"603deb1015ca71be2b73aef0857d77811f352c073b6108d72d9810a30914dff4",
"000102030405060708090a0b0c0d0e0f",
"6bc1bee22e409f96e93d7e117393172a",
"f58c4c04d6e5f1ba779eabfb5f7bfbd6"
);

cipher_kat!(
test_sp800_38a_cbc_aes128_multi_block,
&AES_128,
OperatingMode::CBC,
"2b7e151628aed2a6abf7158809cf4f3c",
"000102030405060708090a0b0c0d0e0f",
"6bc1bee22e409f96e93d7e117393172aae2d8a571e03ac9c9eb76fac45af8e5130c81c46a35ce411e5fbc1191a0a52eff69f2445df4f9b17ad2b417be66c3710",
"7649abac8119b246cee98e9b12e9197d5086cb9b507219ee95db113a917678b273bed6b8e3c1743b7116e69e222295163ff1caa1681fac09120eca307586e1a7"
);

cipher_kat!(
test_sp800_38a_cbc_aes256_multi_block,
&AES_256,
OperatingMode::CBC,
"603deb1015ca71be2b73aef0857d77811f352c073b6108d72d9810a30914dff4",
"000102030405060708090a0b0c0d0e0f",
"6bc1bee22e409f96e93d7e117393172aae2d8a571e03ac9c9eb76fac45af8e5130c81c46a35ce411e5fbc1191a0a52eff69f2445df4f9b17ad2b417be66c3710",
"f58c4c04d6e5f1ba779eabfb5f7bfbd69cfc4e967edb808d679f777bc6702c7d39f23369a9d9bacfa530e26304231461b2eb05e2c39be9fcda6c19078c6a9d1b"
);
}
170 changes: 125 additions & 45 deletions aws-lc-rs/tests/cipher_test.rs
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Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -303,34 +303,16 @@ macro_rules! padded_ecb_pkcs7_kat {

macro_rules! cipher_kat {
($name:ident, $alg:expr, $mode:expr, $constructor:ident, $key:literal, $iv: literal, $plaintext:literal, $ciphertext:literal) => {
#[test]
fn $name() {
let key = from_hex($key).unwrap();
let input = from_hex($plaintext).unwrap();
let expected_ciphertext = from_hex($ciphertext).unwrap();

let iv = from_hex($iv).unwrap();
let fixed_iv = FixedLength::try_from(iv.as_slice()).unwrap();
let context = EncryptionContext::Iv128(fixed_iv);

let unbound_key = UnboundCipherKey::new($alg, &key).unwrap();

let encrypting_key = EncryptingKey::$constructor(unbound_key).unwrap();
assert_eq!($mode, encrypting_key.mode());
assert_eq!($alg, encrypting_key.algorithm());
let mut in_out = input.clone();
let context = encrypting_key
.less_safe_encrypt(in_out.as_mut_slice(), context)
.unwrap();
assert_eq!(expected_ciphertext.as_slice(), in_out);

let unbound_key2 = UnboundCipherKey::new($alg, &key).unwrap();
let decrypting_key = DecryptingKey::$constructor(unbound_key2).unwrap();
assert_eq!($mode, decrypting_key.mode());
assert_eq!($alg, decrypting_key.algorithm());
let plaintext = decrypting_key.decrypt(&mut in_out, context).unwrap();
assert_eq!(input.as_slice(), plaintext);
}
unpadded_cipher_kat!(
$name,
$alg,
$mode,
$constructor,
$key,
$iv,
$plaintext,
$ciphertext
);

streaming_cipher_kat!(
$name,
Expand All @@ -347,47 +329,64 @@ macro_rules! cipher_kat {
};
}

macro_rules! ecb_kat {
($name:ident, $alg:expr, $key:literal, $plaintext:literal, $ciphertext:literal) => {
macro_rules! unpadded_cipher_kat {
($name:ident, $alg:expr, $mode:expr, $constructor:ident, $key:literal, $iv: literal, $plaintext:literal, $ciphertext:literal) => {
#[test]
fn $name() {
let key = from_hex($key).unwrap();
let input = from_hex($plaintext).unwrap();
let expected_ciphertext = from_hex($ciphertext).unwrap();

let context = if $iv.len() == 0 {
EncryptionContext::None
} else {
let iv = from_hex($iv).unwrap();
let fixed_iv = FixedLength::try_from(iv.as_slice()).unwrap();
EncryptionContext::Iv128(fixed_iv)
};

let unbound_key = UnboundCipherKey::new($alg, &key).unwrap();

let encrypting_key = EncryptingKey::ecb(unbound_key).unwrap();
assert_eq!(OperatingMode::ECB, encrypting_key.mode());
let encrypting_key = EncryptingKey::$constructor(unbound_key).unwrap();
assert_eq!($mode, encrypting_key.mode());
assert_eq!($alg, encrypting_key.algorithm());
let mut in_out = input.clone();
let context = encrypting_key
.less_safe_encrypt(in_out.as_mut_slice(), EncryptionContext::None)
.less_safe_encrypt(in_out.as_mut_slice(), context)
.unwrap();
assert_eq!(expected_ciphertext.as_slice(), in_out);

let unbound_key2 = UnboundCipherKey::new($alg, &key).unwrap();
let decrypting_key = DecryptingKey::ecb(unbound_key2).unwrap();
assert_eq!(OperatingMode::ECB, decrypting_key.mode());
let decrypting_key = DecryptingKey::$constructor(unbound_key2).unwrap();
assert_eq!($mode, decrypting_key.mode());
assert_eq!($alg, decrypting_key.algorithm());
let plaintext = decrypting_key.decrypt(&mut in_out, context).unwrap();
assert_eq!(input.as_slice(), plaintext);
}
};
($name:ident, $alg:expr, $key:literal, $plaintext:literal) => {

($name:ident, $alg:expr, $mode:expr, $constructor:ident, $key:literal, $iv: literal, $plaintext:literal) => {
#[test]
fn $name() {
let key = from_hex($key).unwrap();
let input = from_hex($plaintext).unwrap();

let context = if $iv.len() == 0 {
EncryptionContext::None
} else {
let iv = from_hex($iv).unwrap();
let fixed_iv = FixedLength::try_from(iv.as_slice()).unwrap();
EncryptionContext::Iv128(fixed_iv)
};

let unbound_key = UnboundCipherKey::new($alg, &key).unwrap();

let encrypting_key = EncryptingKey::ecb(unbound_key).unwrap();
assert_eq!(OperatingMode::ECB, encrypting_key.mode());
let encrypting_key = EncryptingKey::$constructor(unbound_key).unwrap();
assert_eq!($mode, encrypting_key.mode());
assert_eq!($alg, encrypting_key.algorithm());
let mut in_out = input.clone();
encrypting_key
.less_safe_encrypt(in_out.as_mut_slice(), EncryptionContext::None)
.less_safe_encrypt(in_out.as_mut_slice(), context)
.expect_err("expected encryption failure");
}
};
Expand Down Expand Up @@ -856,48 +855,66 @@ padded_ecb_pkcs7_kat!(
"f6dc9e368d2cdf6a2e97a022876eb9f2"
);

ecb_kat!(
unpadded_cipher_kat!(
test_kat_aes_128_ecb_16_bytes,
&AES_128,
OperatingMode::ECB,
ecb,
"f8efb984d9e813c96a79020bdfbb6032",
"", // ECB does not have an IV
"c4a500e39307dbe7727b5b3a36660f70",
"1eea416d959f747da26d48d2df11d205"
);

ecb_kat!(
unpadded_cipher_kat!(
test_kat_aes_192_ecb_16_bytes,
&AES_192,
OperatingMode::ECB,
ecb,
"4c6994ffa9dcdc805b60c2c0095334c42d95a8fc0ca5b080",
"", // ECB does not have an IV
"c4a500e39307dbe7727b5b3a36660f70",
"1f021658980c025396455f7bb7e01d07"
);

ecb_kat!(
unpadded_cipher_kat!(
test_kat_aes_128_ecb_15_bytes,
&AES_128,
OperatingMode::ECB,
ecb,
"f8efb984d9e813c96a79020bdfbb6032",
"", // ECB does not have an IV
"c4a500e39307dbe7727b5b3a36660f"
);

ecb_kat!(
unpadded_cipher_kat!(
test_kat_aes_192_ecb_15_bytes,
&AES_192,
OperatingMode::ECB,
ecb,
"c88f5b00a4ef9a6840e2acaf33f00a3bdc4e25895303fa72",
"", // ECB does not have an IV
"c4a500e39307dbe7727b5b3a36660f"
);

ecb_kat!(
unpadded_cipher_kat!(
test_kat_aes_256_ecb_16_bytes,
&AES_256,
OperatingMode::ECB,
ecb,
"d3c9173cbfc65d0e2b6f43ae57c2a6550b756f487bbb7b6404efec69aa74d411",
"", // ECB does not have an IV
"109082176cf2a9488b0cd887386bb84a",
"c8c9fece9883b26c0ca58e610493a318"
);

ecb_kat!(
unpadded_cipher_kat!(
test_kat_aes_256_ecb_15_bytes,
&AES_256,
OperatingMode::ECB,
ecb,
"d3c9173cbfc65d0e2b6f43ae57c2a6550b756f487bbb7b6404efec69aa74d411",
"", // ECB does not have an IV
"109082176cf2a9488b0cd887386bb8"
);

Expand Down Expand Up @@ -1029,3 +1046,66 @@ cipher_kat!(
"9c1675a95f573b4504e6bc5275d0df",
"b8e816bd9e74adebdacf9036cbda41"
);

unpadded_cipher_kat!(
test_kat_aes_128_cbc_16_bytes_raw,
&AES_128,
OperatingMode::CBC,
cbc,
"000102030405060708090a0b0c0d0e0f",
"00000000000000000000000000000000",
"00112233445566778899aabbccddeeff",
"69c4e0d86a7b0430d8cdb78070b4c55a"
);

unpadded_cipher_kat!(
test_kat_aes_192_cbc_16_bytes_raw,
&AES_192,
OperatingMode::CBC,
cbc,
"e08c15411774ec4a908b64eadc6ac4199c7cd453f3aaef53",
"00000000000000000000000000000000",
"00112233445566778899aabbccddeeff",
"fc7f57e545e92c0a0b364c3086d49bf0"
);

unpadded_cipher_kat!(
test_kat_aes_256_cbc_16_bytes_raw,
&AES_256,
OperatingMode::CBC,
cbc,
"000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f",
"00000000000000000000000000000000",
"00112233445566778899aabbccddeeff",
"8ea2b7ca516745bfeafc49904b496089"
);

unpadded_cipher_kat!(
test_kat_aes_128_cbc_15_bytes_raw,
&AES_128,
OperatingMode::CBC,
cbc,
"000102030405060708090a0b0c0d0e0f",
"00000000000000000000000000000000",
"00112233445566778899aabbccddee"
);

unpadded_cipher_kat!(
test_kat_aes_192_cbc_15_bytes_raw,
&AES_192,
OperatingMode::CBC,
cbc,
"e08c15411774ec4a908b64eadc6ac4199c7cd453f3aaef53",
"00000000000000000000000000000000",
"00112233445566778899aabbccddee"
);

unpadded_cipher_kat!(
test_kat_aes_256_cbc_15_bytes_raw,
&AES_256,
OperatingMode::CBC,
cbc,
"000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f",
"00000000000000000000000000000000",
"00112233445566778899aabbccddee"
);
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