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-rw-r--r--src/cipher.cpp21
1 files changed, 10 insertions, 11 deletions
diff --git a/src/cipher.cpp b/src/cipher.cpp
index 2202746..7bb11b8 100644
--- a/src/cipher.cpp
+++ b/src/cipher.cpp
@@ -23,11 +23,9 @@ olm::Cipher::~Cipher() {
namespace {
-static const std::size_t SHA256_LENGTH = 32;
-
struct DerivedKeys {
olm::Aes256Key aes_key;
- std::uint8_t mac_key[SHA256_LENGTH];
+ std::uint8_t mac_key[olm::KEY_LENGTH];
olm::Aes256Iv aes_iv;
};
@@ -37,16 +35,17 @@ static void derive_keys(
std::uint8_t const * key, std::size_t key_length,
DerivedKeys & keys
) {
- std::uint8_t derived_secrets[80];
+ std::uint8_t derived_secrets[2 * olm::KEY_LENGTH + olm::IV_LENGTH];
olm::hkdf_sha256(
key, key_length,
nullptr, 0,
kdf_info, kdf_info_length,
derived_secrets, sizeof(derived_secrets)
);
- std::memcpy(keys.aes_key.key, derived_secrets, 32);
- std::memcpy(keys.mac_key, derived_secrets + 32, 32);
- std::memcpy(keys.aes_iv.iv, derived_secrets + 64, 16);
+ std::uint8_t const * pos = derived_secrets;
+ pos = olm::load_array(keys.aes_key.key, pos);
+ pos = olm::load_array(keys.mac_key, pos);
+ pos = olm::load_array(keys.aes_iv.iv, pos);
olm::unset(derived_secrets);
}
@@ -84,7 +83,7 @@ std::size_t olm::CipherAesSha256::encrypt(
return std::size_t(-1);
}
struct DerivedKeys keys;
- std::uint8_t mac[SHA256_LENGTH];
+ std::uint8_t mac[olm::SHA256_OUTPUT_LENGTH];
derive_keys(kdf_info, kdf_info_length, key, key_length, keys);
@@ -93,7 +92,7 @@ std::size_t olm::CipherAesSha256::encrypt(
);
olm::hmac_sha256(
- keys.mac_key, SHA256_LENGTH, output, output_length - MAC_LENGTH, mac
+ keys.mac_key, olm::KEY_LENGTH, output, output_length - MAC_LENGTH, mac
);
std::memcpy(output + output_length - MAC_LENGTH, mac, MAC_LENGTH);
@@ -116,12 +115,12 @@ std::size_t olm::CipherAesSha256::decrypt(
std::uint8_t * plaintext, std::size_t max_plaintext_length
) const {
DerivedKeys keys;
- std::uint8_t mac[SHA256_LENGTH];
+ std::uint8_t mac[olm::SHA256_OUTPUT_LENGTH];
derive_keys(kdf_info, kdf_info_length, key, key_length, keys);
olm::hmac_sha256(
- keys.mac_key, SHA256_LENGTH, input, input_length - MAC_LENGTH, mac
+ keys.mac_key, olm::KEY_LENGTH, input, input_length - MAC_LENGTH, mac
);
std::uint8_t const * input_mac = input + input_length - MAC_LENGTH;