diff --git a/include/polarssl/arc4.h b/include/polarssl/arc4.h
index 9de0577..49cc37c 100644
--- a/include/polarssl/arc4.h
+++ b/include/polarssl/arc4.h
@@ -20,6 +20,10 @@
  *  You should have received a copy of the GNU General Public License along
  *  with this program; if not, write to the Free Software Foundation, Inc.,
  *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * \warning   ARC4 is considered a weak cipher and its use constitutes a
+ *            security risk. We recommend considering stronger ciphers instead.
+ *
  */
 #ifndef POLARSSL_ARC4_H
 #define POLARSSL_ARC4_H
@@ -42,6 +46,11 @@
 
 /**
  * \brief          ARC4 context structure
+ *
+ * \warning        ARC4 is considered a weak cipher and its use constitutes a
+ *                 security risk. We recommend considering stronger ciphers
+ *                 instead.
+ *
  */
 typedef struct
 {
@@ -55,6 +64,11 @@
  * \brief          Initialize ARC4 context
  *
  * \param ctx      ARC4 context to be initialized
+ *
+ * \warning        ARC4 is considered a weak cipher and its use constitutes a
+ *                 security risk. We recommend considering stronger ciphers
+ *                 instead.
+ *
  */
 void arc4_init( arc4_context *ctx );
 
@@ -62,6 +76,11 @@
  * \brief          Clear ARC4 context
  *
  * \param ctx      ARC4 context to be cleared
+ *
+ * \warning        ARC4 is considered a weak cipher and its use constitutes a
+ *                 security risk. We recommend considering stronger ciphers
+ *                 instead.
+ *
  */
 void arc4_free( arc4_context *ctx );
 
@@ -71,6 +90,11 @@
  * \param ctx      ARC4 context to be setup
  * \param key      the secret key
  * \param keylen   length of the key, in bytes
+ *
+ * \warning        ARC4 is considered a weak cipher and its use constitutes a
+ *                 security risk. We recommend considering stronger ciphers
+ *                 instead.
+ *
  */
 void arc4_setup( arc4_context *ctx, const unsigned char *key,
                  unsigned int keylen );
@@ -84,6 +108,11 @@
  * \param output   buffer for the output data
  *
  * \return         0 if successful
+ *
+ * \warning        ARC4 is considered a weak cipher and its use constitutes a
+ *                 security risk. We recommend considering stronger ciphers
+ *                 instead.
+ *
  */
 int arc4_crypt( arc4_context *ctx, size_t length, const unsigned char *input,
                 unsigned char *output );
@@ -104,6 +133,11 @@
  * \brief          Checkup routine
  *
  * \return         0 if successful, or 1 if the test failed
+ *
+ * \warning        ARC4 is considered a weak cipher and its use constitutes a
+ *                 security risk. We recommend considering stronger ciphers
+ *                 instead.
+ *
  */
 int arc4_self_test( int verbose );