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authorRichard van der Hoff <github@rvanderhoff.org.uk>2016-09-05 10:36:43 +0100
committerGitHub <noreply@github.com>2016-09-05 10:36:43 +0100
commit9d16d820890e7b301baa8b69694aaea19f9bfc7f (patch)
tree659be65eb1b131073bf9580292214b3fc24aa982 /src/cipher.cpp
parent0c3f527dfd46d3056d5b3690836c102f0e0adfb4 (diff)
parent39212987bdef8e16794e756e3c78b531be25b70a (diff)
Merge pull request #13 from matrix-org/rav/split_out_key_lengths
Create new constants for key lengths, etc
Diffstat (limited to 'src/cipher.cpp')
-rw-r--r--src/cipher.cpp12
1 files changed, 8 insertions, 4 deletions
diff --git a/src/cipher.cpp b/src/cipher.cpp
index 8c3de92..8e3d7a5 100644
--- a/src/cipher.cpp
+++ b/src/cipher.cpp
@@ -17,11 +17,13 @@
#include "olm/memory.hh"
#include <cstring>
+const std::size_t HMAC_KEY_LENGTH = 32;
+
namespace {
struct DerivedKeys {
olm::Aes256Key aes_key;
- std::uint8_t mac_key[olm::KEY_LENGTH];
+ std::uint8_t mac_key[HMAC_KEY_LENGTH];
olm::Aes256Iv aes_iv;
};
@@ -31,7 +33,9 @@ static void derive_keys(
std::uint8_t const * key, std::size_t key_length,
DerivedKeys & keys
) {
- std::uint8_t derived_secrets[2 * olm::KEY_LENGTH + olm::IV_LENGTH];
+ std::uint8_t derived_secrets[
+ AES256_KEY_LENGTH + HMAC_KEY_LENGTH + AES256_IV_LENGTH
+ ];
_olm_crypto_hkdf_sha256(
key, key_length,
nullptr, 0,
@@ -81,7 +85,7 @@ size_t aes_sha_256_cipher_encrypt(
);
_olm_crypto_hmac_sha256(
- keys.mac_key, olm::KEY_LENGTH, output, output_length - MAC_LENGTH, mac
+ keys.mac_key, HMAC_KEY_LENGTH, output, output_length - MAC_LENGTH, mac
);
std::memcpy(output + output_length - MAC_LENGTH, mac, MAC_LENGTH);
@@ -113,7 +117,7 @@ size_t aes_sha_256_cipher_decrypt(
derive_keys(c->kdf_info, c->kdf_info_length, key, key_length, keys);
_olm_crypto_hmac_sha256(
- keys.mac_key, olm::KEY_LENGTH, input, input_length - MAC_LENGTH, mac
+ keys.mac_key, HMAC_KEY_LENGTH, input, input_length - MAC_LENGTH, mac
);
std::uint8_t const * input_mac = input + input_length - MAC_LENGTH;