The recent security incident triggered a discussion how to secure ssh/gpg keys.
One way I want to focus on here (because it is the way I want to use at home), is to store the keys on a crypto card. I did some research for suitable crypto cards and found one which is called Feitian PKI Smartcard, and one which is called OpenPGP card. The OpenPGP card also exists in a USB version (basically a small version of the card is already integrated into a small USB card reader).
The Feitian card is reported to be able to handle RSA keys upto 2048 bits. They do not seem to handle DSA (or ECDSA) keys. The smartcard quick starter guide they have (the Tuning smartcard file system part) tells how to change the parameters of the card to store upto 9 keys on it.
The spec of the OpenPGP card tells that it supports RSA keys upto 3072 bits, but there are reports that it is able to handle RSA keys upto 4096 bits (you need to have at least GPG 2.0.18 to handle that big keys on the crypto card). It looks to me like the card is not handle DSA (or ECDSA) cards. There are only slots for upto 3 keys on it.
If I go this way, I would also need a card reader. It seems a class 3 one (hardware PIN pad and display) would be the most “future-proof” way to go ahead. I found a Reiner SCT cyberJack secoder card reader, which is believed to be supported by OpenSC and seems to be a good balance between cost and features of the Reiner SCT card readers.
If anyone reading this can suggest a better crypto card (keys upto 4096 bits, more than 3 slots, and/or DSA/ECDSA support), or a better card reader, or has any practical experience with any of those components on FreeBSD, please add a comment.