NAME

signify — cryptographically sign and verify files

SYNOPSIS

signify

-C [-q] [-p pubkey] [-t keytype] -x sigfile [file ...]

signify

-G [-n] [-c comment] -p pubkey -s seckey

signify

-S [-enz] [-x sigfile] -s seckey -m message

signify

-V [-eqz] [-p pubkey] [-t keytype] [-x sigfile] -m message

DESCRIPTION

The signify utility creates and verifies cryptographic signatures. A signature verifies the integrity of a message. The mode of operation is selected with the following options:

-C

Verify a signed checksum list, and then verify the checksum for each file. If no files are specified, all of them are checked. sigfile should be the signed output of sha256(1).

-G

Generate a new key pair. Keynames should follow the convention of keyname.pub and keyname.sec for the public and secret keys, respectively.

-S

Sign the specified message file and create a signature.

-V

Verify the message and signature match.

The other options are as follows:

-c comment

Specify the comment to be added during key generation.

-e

When signing, embed the message after the signature. When verifying, extract the message from the signature. (This requires that the signature was created using -e and creates a new message file as output.)

-m message

When signing, the file containing the message to sign. When verifying, the file containing the message to verify. When verifying with -e, the file to create.

-n

When generating a key pair, do not ask for a passphrase. Otherwise, signify will prompt the user for a passphrase to protect the secret key. When signing with -z, store a zero time stamp in the gzip(1) header.

-p pubkey

Public key produced by -G, and used by -V to check a signature.

-q

Quiet mode. Suppress informational output.

-s seckey

Secret (private) key produced by -G, and used by -S to sign a message.

-t keytype

When deducing the correct key to check a signature, make sure the actual key matches /etc/signify/*-keytype.pub.

-x sigfile

The signature file to create or verify. The default is message.sig.

-z

Sign and verify gzip(1) archives, where the signing data is embedded in the gzip(1) header.

The key and signature files created by signify have the same format. The first line of the file is a free form text comment that may be edited, so long as it does not exceed a single line. Signature comments will be generated based on the name of the secret key used for signing. This comment can then be used as a hint for the name of the public key when verifying. The second line of the file is the actual key or signature base64 encoded.

EXIT STATUS

The signify utility exits 0 on success, and >0 if an error occurs. It may fail because of one of the following reasons:

• Some necessary files do not exist.
• Entered passphrase is incorrect.
• The message file was corrupted and its signature does not match.
• The message file is too large.

EXAMPLES

Create a new key pair:

$ signify -G -p newkey.pub -s newkey.sec

Sign a file, specifying a signature name:

$ signify -S -s key.sec -m message.txt -x msg.sig

Verify a signature, using the default signature name:

$ signify -V -p key.pub -m generalsorders.txt

Verify a release directory containing SHA256.sig and a full set of release files:

$ signify -C -p /etc/signify/openbsd-77-base.pub -x SHA256.sig

Verify a bsd.rd before an upgrade:

$ signify -C -p /etc/signify/openbsd-77-base.pub -x SHA256.sig bsd.rd

Sign a gzip archive:

$ signify -Sz -s key-arc.sec -m in.tgz -x out.tgz

Verify a gzip pipeline:

$ ftp url | signify -Vz -t arc | tar ztf -

SEE ALSO

gzip(1), sha256(1)

HISTORY

The signify command first appeared in OpenBSD 5.5.

AUTHORS

Ted Unangst <tedu@openbsd.org> and Marc Espie <espie@openbsd.org>.