diff --git a/include/mbedtls/hkdf.h b/include/mbedtls/hkdf.h
index 2e225cb..699c6d9 100644
--- a/include/mbedtls/hkdf.h
+++ b/include/mbedtls/hkdf.h
@@ -65,10 +65,10 @@
  *  \return An MBEDTLS_ERR_MD_* error for errors returned from the underlying
  *          MD layer.
  */
-int mbedtls_hkdf( const mbedtls_md_info_t *md, const unsigned char *salt,
-                  size_t salt_len, const unsigned char *ikm, size_t ikm_len,
-                  const unsigned char *info, size_t info_len,
-                  unsigned char *okm, size_t okm_len );
+int mbedtls_hkdf(const mbedtls_md_info_t *md, const unsigned char *salt,
+                 size_t salt_len, const unsigned char *ikm, size_t ikm_len,
+                 const unsigned char *info, size_t info_len,
+                 unsigned char *okm, size_t okm_len);
 
 /**
  *  \brief  Take the input keying material \p ikm and extract from it a
@@ -94,10 +94,10 @@
  *  \return An MBEDTLS_ERR_MD_* error for errors returned from the underlying
  *          MD layer.
  */
-int mbedtls_hkdf_extract( const mbedtls_md_info_t *md,
-                          const unsigned char *salt, size_t salt_len,
-                          const unsigned char *ikm, size_t ikm_len,
-                          unsigned char *prk );
+int mbedtls_hkdf_extract(const mbedtls_md_info_t *md,
+                         const unsigned char *salt, size_t salt_len,
+                         const unsigned char *ikm, size_t ikm_len,
+                         unsigned char *prk);
 
 /**
  *  \brief  Expand the supplied \p prk into several additional pseudorandom
@@ -125,9 +125,9 @@
  *  \return An MBEDTLS_ERR_MD_* error for errors returned from the underlying
  *          MD layer.
  */
-int mbedtls_hkdf_expand( const mbedtls_md_info_t *md, const unsigned char *prk,
-                         size_t prk_len, const unsigned char *info,
-                         size_t info_len, unsigned char *okm, size_t okm_len );
+int mbedtls_hkdf_expand(const mbedtls_md_info_t *md, const unsigned char *prk,
+                        size_t prk_len, const unsigned char *info,
+                        size_t info_len, unsigned char *okm, size_t okm_len);
 
 #ifdef __cplusplus
 }