diff --git a/libraries/ssh_crypto.rb b/libraries/ssh_crypto.rb
index e54674c..c06630f 100644
--- a/libraries/ssh_crypto.rb
+++ b/libraries/ssh_crypto.rb
@@ -123,7 +123,7 @@ def valid_kexs # rubocop:disable Metrics/CyclomaticComplexity, Metrics/MethodLen
 
   def valid_macs # rubocop:disable Metrics/CyclomaticComplexity, Metrics/MethodLength
     # define a set of default MACs
-    macs66 = 'hmac-sha2-512-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-ripemd160-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-512,hmac-sha2-256,hmac-ripemd160'
+    macs66 = 'hmac-sha2-512-etm@openssh.com,hmac-sha2-256-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-512,hmac-sha2-256'
     macs59 = 'hmac-sha2-512,hmac-sha2-256,hmac-ripemd160'
     macs53 = 'hmac-ripemd160,hmac-sha1'
     macs = macs59