feat(crypto): Add a method to get the algorithm of the public backup key

Author: poljar

crates/matrix-sdk-crypto/src/backups/keys/backup.rs

@@ -63,6 +63,11 @@ impl MegolmV1BackupKey {
         key
     }
 
+    /// Get the full name of the backup algorithm this backup key supports.
+    pub fn backup_algorithm(&self) -> &str {
+        "m.megolm_backup.v1.curve25519-aes-sha2"
+    }
+
     /// Get all the signatures of this `MegolmV1BackupKey`.
     pub fn signatures(&self) -> BTreeMap<UserId, BTreeMap<DeviceKeyId, String>> {
         self.inner.signatures.to_owned()

crates/matrix-sdk-crypto/src/backups/keys/recovery.rs

@@ -228,8 +228,8 @@ impl RecoveryKey {
             .expect("Can't generate a libom PkDecryption object from our private key")
     }
 
-    /// Extract the public key from this `RecoveryKey`.
-    pub fn public_key(&self) -> MegolmV1BackupKey {
+    /// Extract the megolm.v1 public key from this `RecoveryKey`.
+    pub fn megolm_v1_public_key(&self) -> MegolmV1BackupKey {
         let pk = self.get_pk_decrytpion();
         let public_key = MegolmV1BackupKey::new(pk.public_key(), None);
         public_key

crates/matrix-sdk-crypto/src/backups/mod.rs

@@ -417,7 +417,7 @@ mod test {
         assert_eq!(counts.backed_up, 0, "No room keys have been backed up yet");
 
         let recovery_key = RecoveryKey::new().expect("Can't create new recovery key");
-        let backup_key = recovery_key.public_key();
+        let backup_key = recovery_key.megolm_v1_public_key();
         backup_key.set_version("1".to_owned());
 
         backup_machine.enable_backup_v1(backup_key).await?;