diff --git a/include/openthread/instance.h b/include/openthread/instance.h
index ced184f73..c766b4071 100644
--- a/include/openthread/instance.h
+++ b/include/openthread/instance.h
@@ -53,7 +53,7 @@ extern "C" {
  * @note This number versions both OpenThread platform and user APIs.
  *
  */
-#define OPENTHREAD_API_VERSION (273)
+#define OPENTHREAD_API_VERSION (274)
 
 /**
  * @addtogroup api-instance
diff --git a/include/openthread/platform/crypto.h b/include/openthread/platform/crypto.h
index 9d9981990..69253bb0d 100644
--- a/include/openthread/platform/crypto.h
+++ b/include/openthread/platform/crypto.h
@@ -337,7 +337,7 @@ otError otPlatCryptoHmacSha256Deinit(otCryptoContext *aContext);
  * Start HMAC operation.
  *
  * @param[in]  aContext           Context for HMAC operation.
- * @param[in]  aKey               Key material to be used for for HMAC operation.
+ * @param[in]  aKey               Key material to be used for HMAC operation.
  *
  * @retval OT_ERROR_NONE          Successfully started HMAC operation.
  * @retval OT_ERROR_FAILED        Failed to start HMAC operation.