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authorRichard van der Hoff <richard@matrix.org>2016-09-02 15:11:14 +0100
committerRichard van der Hoff <richard@matrix.org>2016-09-02 15:11:14 +0100
commit39212987bdef8e16794e756e3c78b531be25b70a (patch)
tree659be65eb1b131073bf9580292214b3fc24aa982 /include/olm
parent0c3f527dfd46d3056d5b3690836c102f0e0adfb4 (diff)
Create new constants for key lengths, etc
We were using olm::KEY_LENGTH for everything under the sun which happened to be 32 bytes long, and making a bunch of assumptions in the process. Create a bunch of new constants (as C #defines rather than C++ consts so that I can use them in another forthcoming refactor).
Diffstat (limited to 'include/olm')
-rw-r--r--include/olm/crypto.h31
-rw-r--r--include/olm/crypto.hh15
-rw-r--r--include/olm/ratchet.hh7
3 files changed, 41 insertions, 12 deletions
diff --git a/include/olm/crypto.h b/include/olm/crypto.h
index 31b9b60..325080e 100644
--- a/include/olm/crypto.h
+++ b/include/olm/crypto.h
@@ -27,7 +27,36 @@
extern "C" {
#endif
-const size_t SHA256_OUTPUT_LENGTH = 32;
+/** length of a sha256 hash */
+#define SHA256_OUTPUT_LENGTH 32
+
+/** length of a public or private Curve25519 key */
+#define CURVE25519_KEY_LENGTH 32
+
+/** length of the shared secret created by a Curve25519 ECDH operation */
+#define CURVE25519_SHARED_SECRET_LENGTH 32
+
+/** amount of random data required to create a Curve25519 keypair */
+#define CURVE25519_RANDOM_LENGTH CURVE25519_KEY_LENGTH
+
+/** length of a public Ed25519 key */
+#define ED25519_PUBLIC_KEY_LENGTH 32
+
+/** length of a private Ed25519 key */
+#define ED25519_PRIVATE_KEY_LENGTH 64
+
+/** amount of random data required to create a Ed25519 keypair */
+#define ED25519_RANDOM_LENGTH 32
+
+/** length of an Ed25519 signature */
+#define ED25519_SIGNATURE_LENGTH 64
+
+/** length of an aes256 key */
+#define AES256_KEY_LENGTH 32
+
+/** length of an aes256 initialisation vector */
+#define AES256_IV_LENGTH 16
+
/** Computes SHA-256 of the input. The output buffer must be a least 32
* bytes long. */
diff --git a/include/olm/crypto.hh b/include/olm/crypto.hh
index 484dc83..13fd7e9 100644
--- a/include/olm/crypto.hh
+++ b/include/olm/crypto.hh
@@ -25,23 +25,18 @@
namespace olm {
-static const std::size_t ED25519_PRIVATE_KEY_LENGTH = 64;
-static const std::size_t KEY_LENGTH = 32;
-static const std::size_t SIGNATURE_LENGTH = 64;
-static const std::size_t IV_LENGTH = 16;
-
struct Curve25519PublicKey {
- std::uint8_t public_key[KEY_LENGTH];
+ std::uint8_t public_key[CURVE25519_KEY_LENGTH];
};
struct Curve25519KeyPair : public Curve25519PublicKey {
- std::uint8_t private_key[KEY_LENGTH];
+ std::uint8_t private_key[CURVE25519_KEY_LENGTH];
};
struct Ed25519PublicKey {
- std::uint8_t public_key[KEY_LENGTH];
+ std::uint8_t public_key[ED25519_PUBLIC_KEY_LENGTH];
};
@@ -93,12 +88,12 @@ bool ed25519_verify(
struct Aes256Key {
- std::uint8_t key[KEY_LENGTH];
+ std::uint8_t key[AES256_KEY_LENGTH];
};
struct Aes256Iv {
- std::uint8_t iv[IV_LENGTH];
+ std::uint8_t iv[AES256_IV_LENGTH];
};
diff --git a/include/olm/ratchet.hh b/include/olm/ratchet.hh
index 13f7097..e91d634 100644
--- a/include/olm/ratchet.hh
+++ b/include/olm/ratchet.hh
@@ -21,8 +21,13 @@ struct _olm_cipher;
namespace olm {
-typedef std::uint8_t SharedKey[olm::KEY_LENGTH];
+/** length of a shared key: the root key R(i), chain key C(i,j), and message key
+ * M(i,j)). They are all only used to stuff into HMACs, so could be any length
+ * for that. The chain key and message key are both derived from SHA256
+ * operations, so their length is determined by that. */
+const std::size_t OLM_SHARED_KEY_LENGTH = SHA256_OUTPUT_LENGTH;
+typedef std::uint8_t SharedKey[OLM_SHARED_KEY_LENGTH];
struct ChainKey {
std::uint32_t index;