OpenPGP card

OpenPGP card
This is an image of an OpenPGP card from the vendor ZeitControl. This card is pre-punched to be used in ID-000 readers, as shown below
Card inside USB shell

In cryptography, the OpenPGP card[1] is an ISO/IEC 7816-4, -8 compatible smart card[2] that is integrated with many OpenPGP functions. Using this smart card, various cryptographic tasks (encryption, decryption, digital signing/verification, authentication etc.) can be performed. It allows secure storage of secret key material; all versions of the protocol state, "Private keys and passwords cannot be read from the card with any command or function."[1][3] However, new key pairs may be loaded onto the card at any time, overwriting the existing ones.

The original OpenPGP card was built on BasicCard, and remains available at retail. Several mutually compatible JavaCard implementations of the OpenPGP Card's interface protocol are available as open source software and can be installed on generic JavaCard smart cards, including NFC-enabled cards.[4] Nitrokey[5] and Yubico provide USB tokens implementing the same protocol through smart card emulation.

The smart card daemon, in combination with the supported smart card readers,[6] as implemented in GnuPG, can be used for many cryptographic applications. With gpg-agent in GnuPG 2, an ssh-agent implementation using GnuPG, an OpenPGP card can be used for SSH authentication also.

  1. ^ a b OpenPGP Card specification - version 3.4.1, Achim Pietig, 2020. URL: https://gnupg.org/ftp/specs/OpenPGP-smart-card-application-3.4.1.pdf
  2. ^ The OpenPGP Card - How to use the Fellowship Smartcard - The GnuPG Smartcard HOWTO, Rebecca Ehlers, Thorsten Ehlers, et al., Free Software Foundation Europe e. V., 2005. URL: http://www.gnupg.org/howtos/card-howto/en/ch01.html#id2472312
  3. ^ OpenPGP Card specification - version 1.1, Achim Pietig, PPC Card Systems GmbH, 2004. URL: http://www.g10code.com/docs/openpgp-card-1.1.pdf
  4. ^ Nathan Willis (August 3, 2016). "Free software and smartcards". LWN.net.
  5. ^ Nitrokey, https://www.nitrokey.com/
  6. ^ Required Hardware - How to use the Fellowship Smartcard - The GnuPG Smartcard HOWTO, Rebecca Ehlers, Thorsten Ehlers, et al., Free Software Foundation Europe e. V., 2005. URL: http://www.gnupg.org/howtos/card-howto/en/ch02s02.html#id2519120