469 lines
11 KiB
JavaScript
Executable file
469 lines
11 KiB
JavaScript
Executable file
/*
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Code by Thomas Smith
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*/
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var port = 8080;
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var express = require('express');
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var Buffer = require('buffer').Buffer;
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var CTX = require('milagro-crypto-js')
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var app = express();
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/*
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var cors = require('cors')
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app.use(cors());
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*/
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app.use(express.static('test'));
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//default test
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app.get('/', function(request, response){
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var data = {
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message: 'hello world',
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value: 5
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}
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//response.send('Hey there'+request.ip);
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response.json(data);
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console.log('request from'+request.ip);
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});
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//parameter generation function
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app.get('/param', function(request, response){
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var param = gpGen();
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console.log('Generated Param:' + param);
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response.json(param);
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})
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//combine public keys and return the full combined one - JSON Version
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app.get('/combpk', function(request, response){
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var partials = request.query['PK']
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var parsed = [];
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console.log('Combining...');
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for (var i = partials.length - 1; i >= 0; i--) {
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console.log('PK' +i+ ': '+partials[i]);
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parsed.push(JSON.parse(partials[i]));
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}
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var PK = combine(parsed);
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response.json(PK);
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})
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//byte array version
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app.get('/cmpkstring', function(request, response){
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var ctx = new CTX("BN254CX");
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var partials = request.query['PK']
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//if there is only one key, partials will be an array of the individual bytes
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//if more than one, it will be an array of arrays
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//we need to factor for this in code
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var noOfKeys = request.query['number'];
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var parsed = [];
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if(noOfKeys == partials.length)//if we're submitting more than one key
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{
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console.log('Combining' + noOfKeys + " keys...");
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for (var i = partials.length - 1; i >= 0; i--) {
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console.log('PK' +i+ ': '+partials[i]);
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var bytes = Buffer.from(partials[i].split(','), 'hex');
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console.log(bytes)
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var pk = new ctx.ECP.fromBytes(bytes);
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parsed.push(pk);
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}
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}
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else if(noOfKeys == 1)
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{
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console.log("Combining just one key");
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var bytes = Buffer.from(partials.split(','), 'hex');
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console.log(bytes);
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var pk = new ctx.ECP.fromBytes(bytes);
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parsed.push(pk);
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}
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response.json(combine(parsed));
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})
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//addition function on homomorphically encrypted variables
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//this may need some work, different method of serialisation maybe?
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app.get('/addec', function(request, response){
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var c1 = request.query['C1'];
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var c2 = request.query['C2'];
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var number = request.query['number']; //number of ciphertexts to add
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//all the list of ciphertext objects to give to the function
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var parsed = [];
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var ctx = new CTX("BN254CX");
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console.log('Addec:');
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if(number == c1.length)
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{
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for (var i = 0; i < c1.length; i++) {
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console.log(i + ".C1: " + c1[i]);
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var c1Bytes = Buffer.from(c1[i].split(','), 'hex');
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var newC1 = new ctx.ECP.fromBytes(c1Bytes);
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var cipher =
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{
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C1:newC1,
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C2:null
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};
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parsed.push(cipher);
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}
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for (var j = 0; j < c2.length; j++) {
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console.log(j + ".C2: " + c2[j]);
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var c2Bytes = Buffer.from(c2[j].split(','), 'hex');
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var newC2 = new ctx.ECP.fromBytes(c2Bytes);
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parsed[j].C2 = newC2;
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}
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}
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else if(number == 1)
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{
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console.log("only one cipher");
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var c1Bytes = Buffer.from(c1.split(','), 'hex');
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var newC1 = new ctx.ECP.fromBytes(c1Bytes);
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console.log("C1: " + c1);
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var c2Bytes = Buffer.from(c2.split(','), 'hex');
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var newC2 = new ctx.ECP.fromBytes(c2Bytes);
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console.log("C2: " + c2);
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var cipher =
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{
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C1:newC1,
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C2:newC2
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};
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parsed.push(cipher);
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}
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response.json(add(parsed));
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})
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//tally partially decrypted ciphertexts
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app.get('/tally', function(request, response){
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console.log("called tally");
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var amount = request.query['number'];//number of decryptions taking in
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var paramString = request.query['param'];//event group parameter in JSON
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var partialsStrings = request.query['decs'];//array of partial decryption(s) in bytes
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var ciphertextString = request.query['cipher'];//ciphertext being decrypted in JSON
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//re-build parameters
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var tempParams = JSON.parse(paramString);
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var ctx = new CTX("BN254CX"); //new context we can use
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var n = new ctx.BIG();
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var g1 = new ctx.ECP();
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var g2 = new ctx.ECP2();
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//copying the values
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n.copy(tempParams.n);
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g1.copy(tempParams.g1);
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g2.copy(tempParams.g2);
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var params = {
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n:n,
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g1:g1,
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g2:g2
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}
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//re-build partial decryptions
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var partials = []
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if(amount == partialsStrings.length)
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{
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console.log(amount + " partial decryptions");
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for(var i = 0; i < partialsStrings.length; i++)
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{
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var bytes = Buffer.from(partialsStrings[i].split(','), 'hex');
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var dec = {
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D:new ctx.ECP.fromBytes(bytes)
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}
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partials.push(dec);
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}
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}
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else if(amount == 1)
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{
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console.log("Only one partial decryption received")
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console.log(paramString)
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var bytes = Buffer.from(partialsStrings.split(','), 'hex');
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var dec = {
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D:new ctx.ECP.fromBytes(bytes)
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}
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partials.push(dec);
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}
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//re-build combined ciphertext
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var tempCipher = JSON.parse(ciphertextString);
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cipher = {
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C1: new ctx.ECP(),
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C2: new ctx.ECP()
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}
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cipher.C1.copy(tempCipher.C1);
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cipher.C2.copy(tempCipher.C2);
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response.json(tally(params, partials, cipher))
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})
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var server = app.listen(port, function(){
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var host = server.address().address;
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var appPort = server.address().port;
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console.log('Server listening on ' + host + ':'+ port);
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});
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/*
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Cryptography functions written by Bingsheng Zhang
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Uses the milagro-crypto-js library at:
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https://github.com/milagro-crypto/milagro-crypto-js
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*/
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//Group parameter generator: returns rng object and generators g1,g2 for G1,G2 as well as order
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gpGen = function(){
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//init, and base generators
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var ctx = new CTX("BN254CX");
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var n=new ctx.BIG(0); n.rcopy(ctx.ROM_CURVE.CURVE_Order);
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//get generator P for G1
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P = new ctx.ECP(0);
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gx = new ctx.BIG(0);
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gx.rcopy(ctx.ROM_CURVE.CURVE_Gx);
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if (ctx.ECP.CURVETYPE != ctx.ECP.MONTGOMERY) {
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gy = new ctx.BIG(0);
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gy.rcopy(ctx.ROM_CURVE.CURVE_Gy);
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P.setxy(gx, gy);
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} else P.setx(gx);
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//get generator Q for G2
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var A=new ctx.BIG(0);
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var B=new ctx.BIG(0);
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A.rcopy(ctx.ROM_CURVE.CURVE_Pxa);
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B.rcopy(ctx.ROM_CURVE.CURVE_Pxb);
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var Qx=new ctx.FP2(0); Qx.bset(A,B);
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A.rcopy(ctx.ROM_CURVE.CURVE_Pya);
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B.rcopy(ctx.ROM_CURVE.CURVE_Pyb);
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var Qy=new ctx.FP2(0); Qy.bset(A,B);
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var Q=new ctx.ECP2();
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Q.setxy(Qy,Qy);
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return{
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n:n,
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g1:P,
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g2:Q
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}
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}
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//creates ElGamal public and secret key
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keyGen=function(params){
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var ctx = new CTX("BN254CX");
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//set rng
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var RAW = [];
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var d = new Date();//time for seed, not secure
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var rng = new ctx.RAND();
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rng.clean();
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RAW[0] = d.getSeconds();
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RAW[1] = d.getMinutes();
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RAW[2] = d.getMilliseconds();
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rng.seed(3, RAW);
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//ElGamal
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var sk = new ctx.BIG(0);
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sk = ctx.BIG.randomnum(params.n,rng);
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var pk = new ctx.ECP(0);
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pk = ctx.PAIR.G1mul(params.g1,sk);
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return{
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PK:pk,
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SK:sk
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}
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}
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//combine multiple public key together
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//the input is an array of PKs
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combine=function(PKs){
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var ctx = new CTX("BN254CX");
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var pk=new ctx.ECP();
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//copy the first pk
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pk.copy(PKs[0]);
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//multiple the rest PKs
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for(i=1;i<PKs.length;i++){
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pk.add(PKs[i]);
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}
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return{
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PK:pk
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}
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}
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//ElGamal encryption
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encrypt=function(params,PK, m){
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var ctx = new CTX("BN254CX");
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//set rand
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var RAW = [];
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var d = new Date();//time for seed, not secure
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var rng = new ctx.RAND();
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rng.clean();
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RAW[0] = d.getSeconds();
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RAW[1] = d.getMinutes();
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RAW[2] = d.getMilliseconds();
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rng.seed(3, RAW);
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var r=new ctx.BIG.randomnum(params.n,rng);
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var M=new ctx.BIG(m);
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var C1=new ctx.ECP();
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C1 = ctx.PAIR.G1mul(params.g1,r);
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var gM=new ctx.ECP();
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gM = ctx.PAIR.G1mul(params.g1,M);
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var C2=new ctx.ECP();
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C2 = ctx.PAIR.G1mul(PK,r);
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C2.mul(r);
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C2.add(gM);
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return{
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C1:C1,
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C2:C2
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}
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}
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//add ciphertexts
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add=function(Ciphers){
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var ctx = new CTX("BN254CX");
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var s1=new ctx.ECP();
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var s2=new ctx.ECP();
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//copy the first cipher
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s1.copy(Ciphers[0].C1);
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s2.copy(Ciphers[0].C2);
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//multiple the rest ciphertexts
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for(i=1;i<Ciphers.length;i++){
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s1.add(Ciphers[i].C1);
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}
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//no idea why I need two loops
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for(j=1;j<Ciphers.length;j++){
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s2.add(Ciphers[j].C2);
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}
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return{
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C1:s1,
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C2:s2
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}
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}
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//ElGamal decryption
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decrypt=function(params,SK, C){
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var ctx = new CTX("BN254CX");
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var D=new ctx.ECP();
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D = ctx.PAIR.G1mul(C.C1,SK);
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var gM=new ctx.ECP();
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gM.copy(C.C2);
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gM.sub(D);
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//search for message by brute force
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var B;
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for (j = 0; j < 1000; j++) {
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//use D as temp var
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B = new ctx.BIG(j);
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D = ctx.PAIR.G1mul(params.g1,B);
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if (D.equals(gM))
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return{
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M:j
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}
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};
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return{
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M: "Error"
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}
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}
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//ElGamal partial decryption
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partDec=function(SK, C){
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var ctx = new CTX("BN254CX");
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var D=new ctx.ECP();
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D = ctx.PAIR.G1mul(C.C1,SK);
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return{
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D: D
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}
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}
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//Tally, combine partial decryption
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//Ds is the array of partial decryptions; C is the ciphertext.
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tally=function(params,Ds, C){
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var ctx = new CTX("BN254CX");
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var D=new ctx.ECP();
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D.copy(Ds[0].D);
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//combine D
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for(i=1;i<Ds.length;i++){
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D.add(Ds[i].D);
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}
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var gM=new ctx.ECP();
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gM.copy(C.C2);
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gM.sub(D);
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//search for message by brute force
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var B;
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for (j = 0; j < 1000; j++) {
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//use D as temp var
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B = new ctx.BIG(j);
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D = ctx.PAIR.G1mul(params.g1,B);
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if (D.equals(gM))
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return{
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M:j
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}
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};
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return{
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M: "Error"
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}
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}
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