diff --git a/rules/S4790/description.adoc b/rules/S4790/description.adoc
index 21ee27f6c6b..1d88bcc1722 100644
--- a/rules/S4790/description.adoc
+++ b/rules/S4790/description.adoc
@@ -1 +1,3 @@
-Cryptographic hash algorithms such as ``++MD2++``, ``++MD4++``, ``++MD5++``, ``++MD6++``, ``++HAVAL-128++``, ``++HMAC-MD5++``, ``++DSA++`` (which uses ``++SHA-1++``), ``++RIPEMD++``, ``++RIPEMD-128++``, ``++RIPEMD-160++``, ``++HMACRIPEMD160++`` and ``++SHA-1++`` are no longer considered secure, because it is possible to have ``++collisions++`` (little computational effort is enough to find two or more different inputs that produce the same hash).
+Cryptographic hash algorithms such as ``++MD2++``, ``++MD4++``, ``++MD5++``, ``++MD6++``, ``++HAVAL-128++``,  ``++DSA++`` (which uses ``++SHA-1++``), ``++RIPEMD++``, ``++RIPEMD-128++``, ``++RIPEMD-160++``and ``++SHA-1++`` are no longer considered secure, because it is possible to have ``++collisions++`` (little computational effort is enough to find two or more different inputs that produce the same hash).
+
+Message authentication code (MAC) algorithms such as ``++HMAC-MD5++`` or ``++HMAC-SHA1++`` use weak hash functions as building blocks. Although they are not all proven to be weak, they are considered legacy algorithms and should be avoided.
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