Is there a portable encryptable address book solution?

Do you by any chance happen to know any portable address book solutions that can also be encrypted? I just want a way to keep all my contacts with their data (phone,email,address,birth date,where I met them,etc.) in one place and be able to carry it around with me to stay organized. Or maybe what I'm looking for is something else? I've never used such a solution before so enlighten me.