Encrypt password in register in sip.conf md5

Couldn’t find the answer to this simple question:
Is it possible to encrypt the password in sip.conf in the line to register to a sip account.
register => user:password@sipdomain

I am NOT refering to encrypted user password, which I know can be done through md5secret

If you encrypted the password you would need to then encrypt the encryption key, and the key you used for that…