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New feature: secret sharing for CA passphrase, based on
OpenXPKI::Crypto::Secret::Split (Shamir's Secret Sharing). Uses a nasty hack to simulate the OpenXPKI class hierarchy, but works for now. Includes two runbooks for a simple CA and one with Secret Sharing.
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‎README.keyceremony-shared-interactive

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This is an example runbook for an interactive key ceremony using Secret Sharing.
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2013-12-16 Martin Bartosch
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Assumptions:
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2048 Bit RSA key protected by a 128 Bit random pass phrase.
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The pass phrase is split into 5 shares, of which 3 will be needed to perform CA operations.
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1. Preparation of CLCA configuration
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export K=3
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export N=5
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rm -rf dummyca/
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mkdir -p dummyca/etc
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mkdir -p dummyca/private/
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chmod 700 dummyca/private/
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cp etc/clca.cfg dummyca/etc/
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cp etc/openssl.cnf dummyca/etc/
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cat <<EOF >>dummyca/etc/clca.cfg
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get_passphrase() {
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../bin/secret get --n $N --k $K
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}
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EOF
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2. Generate CA key and perform secret sharing.
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Required: you need N=5 persons for safekeeping of the CA shares.
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PASSPHRASE=`./bin/secret generate --n $N --k $K` openssl genrsa -aes256 -passout env:PASSPHRASE -out dummyca/private/rsa-rootkey 2048
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Each share holder must copy the displayed share literally and keep it.
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3. Create the CA certificate
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cd dummyca
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../bin/clca initialize
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4. Create initial CRL
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../bin/clca issue_crl
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5. Sign certificate
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../bin/clca certify REQUEST
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‎README.keyceremony-simple-noninteractive

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This is an example runbook for a noninteractive key ceremony using plain/static keys.
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2013-12-16 Martin Bartosch
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Assumptions:
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2048 Bit RSA key protected by the passphrase '1234'.
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1. Preparation of CLCA configuration
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rm -rf dummyca/
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mkdir -p dummyca/etc
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mkdir -p dummyca/private/
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chmod 700 dummyca/private/
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cp etc/clca.cfg dummyca/etc/
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cp etc/openssl.cnf dummyca/etc/
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cat <<EOF >>dummyca/etc/clca.cfg
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get_passphrase() {
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echo "1234"
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}
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EOF
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2. Generate CA key and perform secret sharing.
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PASSPHRASE="1234" openssl genrsa -aes256 -passout env:PASSPHRASE -out dummyca/private/rsa-rootkey 2048
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3. Create the CA certificate
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cd dummyca
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../bin/clca initialize
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4. Create initial CRL
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../bin/clca issue_crl
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5. Sign certificate
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../bin/clca certify REQUEST
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‎bin/secret

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#!/usr/bin/env perl
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#
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# Command line tool wrapper for OpenXPKI Secret Sharing
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# 2013-12-04 Martin Bartosch <[email protected]>
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#
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# Stub implementation for OpenXPKI Crypto Token (only random numbers and prime tests required)
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package DummyToken;
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use strict;
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use warnings;
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sub new {
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my $self = {};
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bless $self;
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return $self;
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}
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sub command {
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my $self = shift;
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my $arg = shift;
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if ($arg->{COMMAND} eq 'create_random') {
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my $len = $arg->{RANDOM_LENGTH};
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my $rand = `openssl rand -base64 $len`;
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if ($? != 0) {
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die "ERROR: could not run openssl";
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}
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chomp $rand;
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if (length($rand) < $len) {
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die "Error: could not create random value. Stopped";
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}
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return $rand;
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}
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if ($arg->{COMMAND} eq 'is_prime') {
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my $result = `openssl prime -hex $arg->{PRIME}`;
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chomp $result;
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if ($? != 0) {
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die "ERROR: could not run openssl";
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}
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if ($result =~ m{ is\ not\ prime \z}xms) {
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return;
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} elsif ($result =~ m{ is\ prime \z}xms) {
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return 1;
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} else {
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die "ERROR: invalid prime test result $result returned from openssl";
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}
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}
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die "token command " . $arg->{COMMAND} . " not implemented";
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}
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package main;
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use strict;
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use warnings;
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use FindBin;
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use lib "$FindBin::Bin/../lib";
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use Getopt::Long;
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use Pod::Usage;
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use OpenXPKI::Crypto::Secret;
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use Data::Dumper;
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use English;
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my $k = 2;
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my $n = 3;
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my $bitlength = 128;
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my $help;
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my $man;
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my $batch;
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GetOptions(
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'help' => \$help,
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'man' => \$man,
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'k=i' => \$k,
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'n=i' => \$n,
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'bitlength=i' => \$bitlength,
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'batch' => \$batch,
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)
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or pod2usage(-verbose => 0);
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pod2usage(-exitstatus => 0, -verbose => 2) if ($man);
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pod2usage(-verbose => 1) if ($help);
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my $secret = OpenXPKI::Crypto::Secret->new(
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{
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TYPE => 'Split',
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QUORUM => {
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N => $n,
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K => $k,
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},
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TOKEN => DummyToken->new(),
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});
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if (! $secret) {
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die "Could not instantiate secret. Stopped";
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}
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my $cmd = shift || exit 0;
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if ($cmd eq 'generate') {
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my @shares = $secret->compute({ BITLENGTH => $bitlength });
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my $secret = $secret->get_secret();
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if ($batch) {
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print "K=$k\n";
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print "N=$n\n";
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print "PASSPHRASE=$secret\n";
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for (my $ii = 0; $ii < scalar @shares; $ii++) {
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print "SHARE[$ii]=$shares[$ii]\n";
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}
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} else {
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print STDERR "Creating shared secret of $bitlength random bits with ($k/$n) quorum.\n\n";
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print STDERR "This program will first print the $n shares to STDERR, clearing the screen\n";
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print STDERR "with 200 newlines after each step.\n";
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print STDERR "After providing the shares the program will print the $bitlength bit phrase\n";
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print STDERR "to STDOUT.\n\n";
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print STDERR "Hit ENTER now to display the first share.\n";
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my $tmp = <>;
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for (my $ii = 0; $ii < $n; $ii++) {
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print STDERR "Share holder #" . ($ii + 1) . ", this is your share:\n";
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print STDERR $shares[$ii] . "\n\n";
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print STDERR "Copy the share and hit ENTER to clear the screen.\n";
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print STDERR "(NOTE: no sensitive data will be displayed immediately after the key press.)\n";
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$tmp = <>;
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for (my $jj = 0; $jj < 200; $jj++) {
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print STDERR "\n";
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}
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print STDERR "Share #" . ($ii + 1) . " has just been displayed.\n";
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print STDERR "Hit ENTER to continue\n\n";
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$tmp = <>;
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}
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print "PASSPHRASE=$secret\n";
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}
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} elsif ($cmd eq 'get') {
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while (! $secret->is_complete()) {
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if (! $batch) {
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for (my $ii = 0; $ii < 200; $ii++) {
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print STDERR "\n";
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}
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print STDERR "Please enter share: ";
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}
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my $line = <>;
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chomp $line;
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$line = uc($line);
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eval {
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$secret->set_secret($line);
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};
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if ($EVAL_ERROR) {
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print STDERR "ERROR: invalid share entered, repeat please\n";
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if (! $batch) {
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sleep 2;
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}
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}
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}
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print "PASSPHRASE=" . $secret->get_secret() . "\n";
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} else {
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print STDERR "ERROR: invalid command '$cmd'\n";
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exit 1;
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}
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__END__
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=head1 NAME
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secret - Secret Splitting
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=head1 USAGE
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secret [OPTIONS] [get|generate]
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=head1 DESCRIPTION
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=head1 OPTIONS
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=over 8
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=item B<--k>
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Quorum value K. Default: 2
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K shares out of N are required to reconstruct the secret.
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=item B<--n>
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Quorum value N. Default: 3
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K shares out of N are required to reconstruct the secret.
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=item B<--batch>
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Batch mode, does not print instructions for humans, instead only outputs the necessary
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information.
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=item B<--help>
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Display a short help summary.
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=item B<--man>
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Display full manual page.
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=back
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=head1 COMMANDS
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=over 8
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=item B<generate>
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This command generates a random number (default: 128 bit), performs the actual secret
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splitting, generates and prints the secret parts. The output in batch mode has the format
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SECRET=....
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SHARE[0]=....
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SHARE[1]=....
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A useful way to hide the output and to provide the data for later processing (e. g. during a key
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ceremony) is to invoke the script via eval `...`:
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eval `./bin/secret generate --k 3 --n 5 --batch`
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After executing ths command you can access the values as shell variables.
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In interactive mode (default) some verbose instructions are printed to STDERR, the final SECRET=...
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is still printed to STOUT. This makes it possible to assign the secret value to a variable and
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continue processing from there:
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PASSPHRASE=`./bin/secret generate --k 3 --n 5` openssl genrsa -aes256 -passout env:PASSPHRASE -out key.pem 2048
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=item B<get>
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After reading the necessary components of the secret this command outputs the reconstructed secret to STDOUT.
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Make sure to specify the same --k and --n parameters as during generation of shared secrets.
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In --batch mode the script reads --k lines from STDIN without printing any information.
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=back
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=head1 EXAMPLES
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