gpg_key_to_web

#!/usr/bin/env bash
##############################################################################
#
# gpg_key_to_web
# -------------------
# Upload a signed, timestamped copy of your gpg public key and fingerprint.
#
# @author Isis Agora Lovecruft, 0x2cdb8b35
# @date 1 April 2012
# @version 0.1.0
#-----------------------------------------------------------------------------
# Changelog:
# v0.1.0: Added features to optionally input OTR fingerprints as well.
##############################################################################

set -efu

function usage ()
{
    echo "$0  [options] <key ID>"
    echo "-------------------------------------------------------------------"
    echo "Prepend a message which includes a timestamp and a display of the "
    echo "key's fingerprints and user IDs (and, also, optionally, and XMPP "
    echo "account with an OTR fingerprint) to a copy of the public key. Then "
    echo "a detached signature file of the public key with prepended message "
    echo "is created, and these can be optionally uploaded to a remote "
    echo "webserver, and/or stored locally in the user's home directory."
    echo "If only the key ID is given, uploading will be left to user."; echo;
    echo "------------------------------------------------------------------"
    echo "<key ID>         the GPG key ID, i.e. \"2cdb8b35\""
    echo;
    echo "Options:"
    echo;
    echo "-u <user>@<host>:<dir>   upload files to webserver"
    echo "-o <outfile>             output to file (default: $HOME/<keyID>.asc"
    echo "-f <otr-fingerprint>     include otr fingerprint <otr-fingerprint>"
    exit 1
}

## @param1 user's keyID
## @param2 fake prompt string
function prepend_gpg_fpr () {
    echo "Creating message to prepend to public key, which will include both"
    echo "a fingerprint and a timestamp ..."; echo;
    FPR=`gpg --fingerprint $1` 
    cat >> $1.prepend<<EOF

$2 gpg --fingerprint $1
$FPR

$2 cat message
EOF
}

## @param $1 user's keyID
## @param $2 otrfpr (from options)
function prepend_otr_fpr () {
    localkeyid=$1
    localotrfpr=$2
    if [ "$localotrfpr" == "" ] ; then
        echo "Include OTR fingerprints also? (Y/n): "
        read yn
        case $yn in 
            n | N | no | No ) echo "Skipping OTR fingerprints..." && return ;;
            * ) echo "Please find your OTR fingerprint from your XMPP/Jabber client, and enter the fingerprint: "
                echo "(ex. \"f9b81df4ba310806b1513680246598a06fc08cdb\")"
                read localotrfpr ;;
        esac    
    fi

    if test -n $localotrfpr ; then
        echo "Please enter the account name (ex. \"isislovecruft@jabber.ccc.de\") for which the given OTR fingerprint is valid: "
        read otrname
        cat >> $1.prepend<<EOF
my xmpp/jabber account and OTR fingerprint are:

   $otrname $localotrfpr

EOF
    else
        return
    fi
}

## @param $1 user's keyID
## @param $2 sigfile
## @param $3 fakeprompt
function prepend_sig_location () {
    RELATIVE=`date`
    cat >> $1.prepend<<EOF
the script which made this file is available here: http://⌘.ws/莨 
and a signature of the complete contents of this file, including this
EOF
    ## include url in prepended message, regardless of uploading
    echo
    echo "Would you also like to include an online location to be specified"
    echo "in the prepended message, so that others can retrieve your key from"
    echo "that location in a more verifiable manner? (We won't upload anything"
    echo "unless you specified a host option.)"; echo;
    echo "Include online location in key message (Y/n):"
    read yn
    case $yn in 
        n | N | no | No )
            cat >> $1.prepend<<EOF
message and the above fingerprint, should have been included with
this key file as $2

EOF
            ;;
        * ) echo "Specify the public web directory which the key will be hosted at, i.e. \"https://foo.bar/about/\" will mean the key will be stored at \"https://foo.bar/about/$1.pub.asc\" and the signature file at \"https://foo.bar/about/$1.pub.sig.asc\" :"
            read url
            cat >> $1.prepend<<EOF
message and the above fingerprint, is available at:

  $url$2

EOF
            ;;
    esac
    cat >> $1.prepend<<EOF

the signature was made with my corresponding private key, and its 
time stamp should be relatively close to...

$3 date
$RELATIVE


EOF
}

## @param $1: user's keyID
## @param $2: the outfile
function add_prepend_and_key ()
{
    if test -r $1.prepend ; then
        ## mv the prepend-message to the actual file
        mv $1.prepend $2
        ## export the public key
        gpg -a -o $1.pub --export $1
        ## and then add it to the actual file
        cat $1.pub >> $2

        if test -r $2 ; then
            echo "Cleaning up temporary files ..."
            rm $1.pub
        else
            echo "Error appending message to public key file. Exiting."
            exit 1
        fi
    else
        echo "Error finding prepend message. Exiting."
        exit 1
    fi
}

## @param $1: the outfile
## @param $2: the sigfile
function create_sig_file ()
{
    if test -r $1; then
        echo "Creating signature file ..."
        gpg -a -o $2 --detach-sign $1
    else
        echo "Error: could not read public key file"
        exit 1
    fi
}

if [[ "$#" == "0" ]] ; then
    usage
else
    cd $HOME
    upload_to=
    outfile=
    otrfpr=
    fakeprompt=$USER"@"$HOSTNAME":~\$"

    while getopts u:o:f: x; do
        case $x in
            u ) upload_to=$OPTARG;;
            o ) outfile=$OPTARG;;
            f ) otrfpr=$OPTARG;;
            * ) usage;;
        esac
    done
    shift $((OPTIND - 1))

    keyid=$1            
    if test -z $outfile ; then
        outfile=$keyid".asc"
        sigfile=$keyid".sig.asc"
    else
        outfile=$outfile
        sigfile=$outfile".sig.asc"
    fi

    echo
    echo "Exporting public key and prepending fingerprint and timestamp ..."
    if ! test -r $1.prepend ; then
        prepend_gpg_fpr $keyid $fakeprompt        
        prepend_otr_fpr $keyid $otrfpr
        prepend_sig_location $keyid $sigfile $fakeprompt
    fi
    add_prepend_and_key $keyid $outfile
    create_sig_file $outfile $sigfile
    echo; echo "Done!"

    if [ "$upload_to" != "" ] ; then
        echo; echo "Uploading to public web root ..."
        scp $outfile $sigfile $upload_to
        echo "Done!"
    fi
    echo "Key file with prepended message at $HOME/$outfile"
    echo "Signature file at $HOME/$sigfile"
    exit 0
fi