This BZ should be blocked by 1862173, as support in cryptsetup is required for Clevis to support this feature. 

Copied from: https://bugzilla.redhat.com/show_bug.cgi?id=1862173#c20

"The basic idea is that unlocking a cryptsetup volume does indeed work using tokens specifying a key description. This causes the device to unlock without prompting the user for a passphrase when invoking cryptsetup luksOpen. The problem here is that cryptsetup luksAddKey does not have this same functionality. cryptsetup luksAddKey requires an existing passphrase to modify the key slots and a new passphrase to add to an open key slot. Our long term goal is to add this feature so that Clevis can invoke cryptsetup luksAddKey and use a key description to fetch the existing password for modification access from the kernel keyring. Currently, cryptsetup luksAddKey only supports a keyfile and stdin for password input as far as I can tell. Adding a key description option for password input would provide us with the ability to remove a rather lengthy workaround to expose passphrases from the kernel keyring securely as a file so that cryptsetup can consume them. Ondrej, I have no strong preference for whether you'd like to take advantage of tokens to accomplish this or whether you'd rather provide a command line parameter to specify the key description. I think we can make either work.

Ondrej and Sergio, we had already discussed this over email, but I just want to make sure that the bugzilla has the appropriate information because my original request was a little too vague for those following along."