diff --git a/include/polarssl/dhm.h b/include/polarssl/dhm.h
index 52b0bf9..d79be91 100644
--- a/include/polarssl/dhm.h
+++ b/include/polarssl/dhm.h
@@ -109,7 +109,7 @@
  * \brief          Create own private value X and export G^X
  *
  * \param ctx      DHM context
- * \param x_size   private value size in bits
+ * \param x_size   private value size in bytes
  * \param output   destination buffer
  * \param olen     must be equal to ctx->P.len
  * \param f_rng    RNG function