.\" generated with Ronn/v0.7.3
.\" http://github.com/rtomayko/ronn/tree/0.7.3
.
.TH "MINISIGN" "1" "January 2016" "" ""
.
.SH "NAME"
\fBminisign\fR \- A dead simple tool to sign files and verify signatures\.
.
.SH "SYNOPSIS"
\fBminisign\fR \-G [\-p pubkey] [\-s seckey] \fBminisign\fR \-S [\-H] [\-x sigfile] [\-s seckey] [\-c untrusted_comment] [\-t trusted_comment] \-m <file> \fBminisign\fR \-V [\-x sigfile] [\-p pubkeyfile | \-P pubkey] [\-o] [\-q] \-m file
.
.SH "DESCRIPTION"
\fBMinisign\fR is a dead simple tool to sign files and verify signatures\.
.
.P
It is portable, lightweight, and uses the highly secure Ed25519 \fIhttp://ed25519\.cr\.yp\.to/\fR public\-key signature system\.
.
.SH "OPTIONS"
These options control the actions of \fBminisign\fR\.
.
.TP
\fB\-G\fR
Generate a new key pair
.
.TP
\fB\-S\fR
Sign a file
.
.TP
\fB\-V\fR
Verify that a signature is valid for a given file
.
.TP
\fB\-m <file>\fR
File to sign/verify
.
.TP
\fB\-o\fR
Combined with \-V, output the file content after verification
.
.TP
\fB\-H\fR
Combined with \-S, pre\-hash in order to sign large files
.
.TP
\fB\-p <pubkeyfile>\fR
Public key file (default: \./minisign\.pub)
.
.TP
\fB\-P <pubkey>\fR
Public key, as a base64 string
.
.TP
\fB\-s <seckey>\fR
Secret key file (default: \./minisign\.key)
.
.TP
\fB\-x <sigfile>\fR
Signature file (default: <file>\.minisig)
.
.TP
\fB\-c <comment>\fR
Add a one\-line untrusted comment
.
.TP
\fB\-t <comment>\fR
Add a one\-line trusted comment
.
.TP
\fB\-q\fR
Quiet mode, suppress output
.
.TP
\fB\-Q\fR
Pretty quiet mode, only print the trusted comment
.
.TP
\fB\-v\fR
Display version number
.
.SH "EXAMPLES"
Creating a key pair
.
.P
\fBminisign\fR \-G
.
.P
The public key is printed and put into the \fBminisign\.pub\fR file\. The secret key is encrypted and saved as a file named \fBminisign\.key\fR\.
.
.P
Signing a file
.
.P
$ \fBminisign\fR \-Sm myfile\.txt
.
.P
Or to include a comment in the signature, that will be verified and displayed when verifying the file:
.
.P
$ \fBminisign\fR \-Sm myfile\.txt \-t \'This comment will be signed as well\'
.
.P
Verifying a file
.
.P
$ \fBminisign\fR \-Vm myfile\.txt \-p <pubkey>
.
.P
or
.
.P
$ \fBminisign\fR \-Vm myfile\.txt \-p signature\.pub
.
.P
This requires the signature \fBmyfile\.txt\.minisig\fR to be present in the same directory\.
.
.P
The public key can either reside in a file (\fB\./minisign\.pub\fR by default) or be directly specified on the command line\.
.
.SH "Notes"
\fBTrusted comments\fR
.
.P
Signature files include an untrusted comment line that can be freely modified, even after signature creation\.
.
.P
They also include a second comment line, that cannot be modified without the secret key\.
.
.P
Trusted comments can be used to add instructions or application\-specific metadata (intended file name, timestamps, resource identifiers, version numbers to prevent downgrade attacks)\.
.
.P
\fBCompatibility with OpenBSD signify\fR
.
.P
Signatures written by \fBminisign\fR can be verified using OpenBSD\'s \fBsignify\fR tool: public key files and signature files are compatible\.
.
.P
However, \fBminisign\fR uses a slightly different format to store secret keys\.
.
.P
\fBMinisign\fR signatures include trusted comments in addition to untrusted comments\. Trusted comments are signed, thus verified, before being displayed\.
.
.P
This adds two lines to the signature files, that signify silently ignores\.
.
.P
\fBPre\-hashing\fR
.
.P
By default, signing and verification require as much memory as the size of the file\.
.
.P
Since \fBMinisign 0\.6\fR, huge files can be signed and verified with very low memory requirements, by pre\-hashing the content\.
.
.P
The \-H command\-line switch, in combination with \-S, generates a pre\-hashed signature (HashEdDSA):
.
.P
$ \fBminisign\fR \-SHm myfile\.txt
.
.P
Verification of such a signature doesn\'t require any specific switch: the appropriate algorithm will automatically be detected\.
.
.P
Signatures generated that way are not compatible with OpenBSD\'s \fBsignify\fR tool and are not compatible with \fBMinisign\fR versions prior to 0\.6
.
.P
\fBSignature format\fR
.
.P
untrusted comment: <arbitrary text> base64(<signature_algorithm> || <key_id> || <signature>) trusted_comment: <arbitrary text> base64(<global_signature>)
.
.P
signature_algorithm: Ed key_id: 8 random bytes, matching the public key signature (PureEdDSA): ed25519(<file data>) signature (HashedEdDSA): ed25519(Blake2b\-512(<file data>)) global_signature: ed25519(<signature> || <trusted_comment>)
.
.P
\fBPublic key format\fR
.
.P
untrusted comment: <arbitrary text> base64(<signature_algorithm> || <key_id> || <public_key>)
.
.P
signature_algorithm: Ed key_id: 8 random bytes public_key: Ed25519 public key
.
.P
\fBSecret key format\fR
.
.P
untrusted comment: <arbitrary text> base64(<signature_algorithm> || <kdf_algorithm> || <cksum_algorithm> || <kdf_salt> || <kdf_opslimit> || <kdf_memlimit> || <keynum_sk>)
.
.P
signature_algorithm: Ed kdf_algorithm: Sc cksum_algorithm: B2 kdf_salt: 32 random bytes kdf_opslimit: crypto_pwhash_scryptsalsa208sha256_OPSLIMIT_SENSITIVE kdf_memlimit: crypto_pwhash_scryptsalsa208sha256_MEMLIMIT_SENSITIVE keynum_sk: <kdf_output> ^ (<key_id> || <secret_key> || <public_key> || <checksum>), 104 bytes key_id: 8 random bytes secret_key: Ed25519 secret key public_key: Ed25519 public key checksum: Blake2b\-256(<signature_algorithm> || <key_id> || <secret_key>), 32 bytes
.
.SH "AUTHOR"
Frank Denis (github [at] pureftpd [dot] org)