ja:Stateless OpenPGP

Stateless OpenPGP (SOP) is a standard for command line interface (CLI) tools to perform OpenPGP operations. It is defined in a dedicated IETF draft outlining its features and syntax.

SOP is a lean approach to signing/verification and encryption/decryption operations on messages. Certificates and/or keys for all operations must be explicitly specified.

Usually private key operations use software keys. However, private key material on hardware security devices can also be used with some SOP implementations.

Many SOP implementations exist and are cross-tested in an interoperability test suite.

Although implementations provide executables of differing names, they all have the same CLI and the core functionality can be used interchangeably.

Installation

Several implementations are available for installation:

• gosop

• rsop

• rsop-oct

• sequoia-sop

Features

While SOP offers a uniform interface, implementations are free to support different subsets of the cryptographic mechanisms that OpenPGP specifies. Different versions of the format as well as hardware backed keys may be supported.

Hardware device support

When using hardware security devices, SOP parameters that usually specify private key material instead only specify public key material.

This public key material serves as an explicit reference to locate and use a hardware device that provides the corresponding private key material.

Tips and tricks

The below examples assume, that the name of the SOP executable (e.g. gosop, rsop, rsop-oct or sqop) is stored in the environment variable $SOP.

Create a private key

To create an OpenPGP transferable secret key (aka. private key) with the User ID <archie@example.org> use:

$ $SOP generate-key "<archie@example.org>" > archie.tsk

Extract certificate

To extract the certificate (aka. public key) from the created transferable secret key use:

$ $SOP extract-cert > archie.cert < archie.tsk

Create detached signature

To create a detached signature for a message use:

$ echo "Hello world" | $SOP sign archie.tsk > msg.sig

Verify detached signature

To verify the detached signature, provide the original message, the signature as well as the OpenPGP certificate:

2024-02-27T17:36:28Z 12b7169b5fc99d1a2d546b8755d1f4d8a355f3cb 12b7169b5fc99d1a2d546b8755d1f4d8a355f3cb mode:binary

$ echo "Hello world"  $SOP verify msg.sig archie.cert

Encrypt a message

Messages can be encrypted by providing the message and the OpenPGP certificate of the recipient:

$ echo "Hello world" | $SOP encrypt archie.cert > encrypted.msg

Decrypt a message

Recipients of encrypted messages can decrypt them by providing the encrypted message and their transferable secret key:

Hello world

$ $SOP decrypt archie.tsk < encrypted.msg

Hello world

$ rsop-oct decrypt archie.cert < encrypted.msg

Create cleartext signed message

Cleartext signed messages can be created by providing the message and the signer's transferable secret key:

-----BEGIN PGP SIGNED MESSAGE-----

Hello world

-----BEGIN PGP SIGNATURE-----

wnUEARYKAB0WIQQStxabX8mdGi1Ua4dV0fTYo1XzywUCZd4eOgAKCRBV0fTYo1Xz
yyqJAQDUD/lbhqOHL/O0cjtytXQXnMOx5twW3FT3RJPlu9JZUAEA2OAMhzLmX6Bb
mXz8Tu0eApqbxu64ksieL8YNN20IwQs=
=77wU
-----END PGP SIGNATURE-----

$ echo "Hello world"  $SOP inline-sign --as clearsigned archie.tsk

See also

• IETF draft

• Interoperability test suite

• OpenPGP for application developers