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).

1 files changed, 30 insertions, 1 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. */