what is the use of Passphrase in client SSL profile ?

Hi Blue_whale,

You have two types of passphrases for certificates:

1. the first is when you upload your PEM, or PFX bundle certificate and this has a password to protect the file.
2. the second is when the master key is a passphrase-protected, and in this case, you have to set the passphrase in the client SSL.

So, it doesn´t change anything for the client, this is an extra security layer to protect the master key and keep it encrypted in the F5, normally if the master key is not encrypted you can export it easily if you have access to the device.

if you need more info about other SSL profile parameters please review this link:

https://my.f5.com/manage/s/article/K14783

Hope it works.