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-rw-r--r--include/axolotl/crypto.hh10
-rw-r--r--include/axolotl/list.hh5
-rw-r--r--src/crypto.cpp38
-rw-r--r--tests/test_crypto.cpp17
4 files changed, 36 insertions, 34 deletions
diff --git a/include/axolotl/crypto.hh b/include/axolotl/crypto.hh
index c8113c5..42c154b 100644
--- a/include/axolotl/crypto.hh
+++ b/include/axolotl/crypto.hh
@@ -42,17 +42,11 @@ struct Aes256Iv {
};
-std::size_t aes_pkcs_7_padded_length(
+std::size_t aes_encrypt_cbc_length(
std::size_t input_length
);
-void aes_pkcs_7_padding(
- std::uint8_t const * input, std::size_t input_length,
- std::uint8_t * output
-);
-
-
void aes_encrypt_cbc(
Aes256Key const & key,
Aes256Iv const & iv,
@@ -61,7 +55,7 @@ void aes_encrypt_cbc(
);
-void aes_decrypt_cbc(
+std::size_t aes_decrypt_cbc(
Aes256Key const & key,
Aes256Iv const & iv,
std::uint8_t const * input, std::size_t input_length,
diff --git a/include/axolotl/list.hh b/include/axolotl/list.hh
index b76abdd..ae41baa 100644
--- a/include/axolotl/list.hh
+++ b/include/axolotl/list.hh
@@ -16,6 +16,11 @@ public:
T const * end() const { return _end; }
/**
+ * Is the list empty?
+ */
+ bool empty() { return _end == _data; }
+
+ /**
* The number of items in the list.
*/
std::size_t size() { return _end - _data; }
diff --git a/src/crypto.cpp b/src/crypto.cpp
index 5277b86..e93a1e9 100644
--- a/src/crypto.cpp
+++ b/src/crypto.cpp
@@ -107,26 +107,13 @@ void axolotl::curve25519_shared_secret(
}
-std::size_t axolotl::aes_pkcs_7_padded_length(
+std::size_t axolotl::aes_encrypt_cbc_length(
std::size_t input_length
) {
return input_length + AES_BLOCK_LENGTH - input_length % AES_BLOCK_LENGTH;
}
-void axolotl::aes_pkcs_7_padding(
- std::uint8_t const * input, std::size_t input_length,
- std::uint8_t * output
-) {
- std::memcpy(output, input, input_length);
- std::size_t padded_length = axolotl::aes_pkcs_7_padded_length(input_length);
- std::uint8_t padding = padded_length - input_length;
- for (std::size_t i = input_length; i < padded_length; ++i) {
- output[i] = padding;
- }
-}
-
-
void axolotl::aes_encrypt_cbc(
axolotl::Aes256Key const & key,
axolotl::Aes256Iv const & iv,
@@ -137,17 +124,28 @@ void axolotl::aes_encrypt_cbc(
::aes_key_setup(key.key, key_schedule, 256);
std::uint8_t input_block[AES_BLOCK_LENGTH];
std::memcpy(input_block, iv.iv, AES_BLOCK_LENGTH);
- for (std::size_t i = 0; i < input_length; i += AES_BLOCK_LENGTH) {
- xor_block<AES_BLOCK_LENGTH>(input_block, &input[i]);
- ::aes_encrypt(input_block, &output[i], key_schedule, 256);
- std::memcpy(input_block, &output[i], AES_BLOCK_LENGTH);
+ while (input_length >= AES_BLOCK_LENGTH) {
+ xor_block<AES_BLOCK_LENGTH>(input_block, input);
+ ::aes_encrypt(input_block, output, key_schedule, 256);
+ std::memcpy(input_block, output, AES_BLOCK_LENGTH);
+ input += AES_BLOCK_LENGTH;
+ output += AES_BLOCK_LENGTH;
+ input_length -= AES_BLOCK_LENGTH;
+ }
+ std::size_t i = 0;
+ for (; i < input_length; ++i) {
+ input_block[i] ^= input[i];
+ }
+ for (; i < AES_BLOCK_LENGTH; ++i) {
+ input_block[i] ^= AES_BLOCK_LENGTH - input_length;
}
+ ::aes_encrypt(input_block, output, key_schedule, 256);
std::memset(key_schedule, 0, sizeof(key_schedule));
std::memset(input_block, 0, sizeof(AES_BLOCK_LENGTH));
}
-void axolotl::aes_decrypt_cbc(
+std::size_t axolotl::aes_decrypt_cbc(
axolotl::Aes256Key const & key,
axolotl::Aes256Iv const & iv,
std::uint8_t const * input, std::size_t input_length,
@@ -164,6 +162,8 @@ void axolotl::aes_decrypt_cbc(
}
}
std::memset(key_schedule, 0, sizeof(key_schedule));
+ std::size_t padding = output[input_length - 1];
+ return (padding > input_length) ? std::size_t(-1) : (input_length - padding);
}
diff --git a/tests/test_crypto.cpp b/tests/test_crypto.cpp
index 78bb738..1838132 100644
--- a/tests/test_crypto.cpp
+++ b/tests/test_crypto.cpp
@@ -73,24 +73,27 @@ TestCase test_case("AES Test Case 1");
axolotl::Aes256Key key = {};
axolotl::Aes256Iv iv = {};
-std::uint8_t input[32] = {};
+std::uint8_t input[16] = {};
std::uint8_t expected[32] = {
0xDC, 0x95, 0xC0, 0x78, 0xA2, 0x40, 0x89, 0x89,
0xAD, 0x48, 0xA2, 0x14, 0x92, 0x84, 0x20, 0x87,
- 0x08, 0xC3, 0x74, 0x84, 0x8C, 0x22, 0x82, 0x33,
- 0xC2, 0xB3, 0x4F, 0x33, 0x2B, 0xD2, 0xE9, 0xD3
+ 0xF3, 0xC0, 0x03, 0xDD, 0xC4, 0xA7, 0xB8, 0xA9,
+ 0x4B, 0xAE, 0xDF, 0xFC, 0x3D, 0x21, 0x4C, 0x38
};
+std::size_t length = axolotl::aes_encrypt_cbc_length(sizeof(input));
+assert_equals(std::size_t(32), length);
+
+
std::uint8_t actual[32] = {};
axolotl::aes_encrypt_cbc(key, iv, input, sizeof(input), actual);
-
assert_equals(expected, actual, 32);
-axolotl::aes_decrypt_cbc(key, iv, expected, sizeof(expected), actual);
-
-assert_equals(input, actual, 32);
+length = axolotl::aes_decrypt_cbc(key, iv, expected, sizeof(expected), actual);
+assert_equals(std::size_t(16), length);
+assert_equals(input, actual, length);
} /* AES Test Case 1 */