Cannot negotiate encryption algorithm

[#1]

Symptoms

Today I want to talk about communication encryption, especially when you are trying to do a remote signon to SAS/CONNECT server on SAS Viya. If you are trying to do that from SAS 9.X, most likely you will get the following error:

ERROR: A communication subsystem partner link setup request failure has occurred.
ERROR: Cannot negotiate encryption algorithm.

Diagnosis

By default, SAS Viya is using SSL for encryption. On the other hand, SAS 9.x is using AES for encryption. That makes encryption settings are incompatible when trying to connect to one another.

Solution

If you want to connect to SAS Viya SAS/CONNECT server, you need to add the following option to your code:

options NETENCRALG=SSL;

You can also adjust this option in the configuration files. More information about NETENCRYPTALGORITHM (NETENCRALG) is available on this page: Encryption in SAS® 9.4, Sixth Edition -> NETENCRYPTALGORITHM System Option