com.daa.verifier.Models.Verifier.java Source code

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Here is the source code for com.daa.verifier.Models.Verifier.java

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package com.daa.verifier.Models;

/**
 *
 * @author DK
 */

import com.google.gson.JsonArray;
import com.google.gson.JsonElement;
import com.google.gson.JsonParser;
import com.daa.verifier.Models.Authenticator.EcDaaSignature;
import com.daa.verifier.Models.Issuer.IssuerPublicKey;
import com.daa.verifier.Controllers.crypto.BNCurve;
import iaik.security.ec.math.curve.ECPoint;

import java.math.BigInteger;
import java.security.NoSuchAlgorithmException;
import java.util.Base64;
import java.util.HashSet;
import java.util.Set;
import java.util.StringJoiner;

/**
 * Class containing the Verifier ECDAA functions
 * @author manudrijvers 
 *
 */

public class Verifier {
    private BNCurve curve;
    public static String JSON_REVOCATION_LIST = "RogueList";
    public static String JSON_REVOCATION_LIST_ENTRY = "RogueListEntry";

    public Verifier(BNCurve curve) {
        this.curve = curve;
    }

    /**
     * Verifies an ECDAA signature
     * @param signature an ECDAA signature
     * @param appId The AppID (i.e. https-URL of TrustFacets object)
     * @param pk the Issuer public key
     * @param revocationList the list of revoked private keys
     * @return true iff the signature is valid
     * @throws NoSuchAlgorithmException
     */
    public boolean verify(EcDaaSignature signature, String appId, IssuerPublicKey pk,
            Set<BigInteger> revocationList) throws NoSuchAlgorithmException {
        boolean success = true;

        // Check that a, b, c, d are in G1
        success &= this.curve.isInG1(signature.r);
        success &= this.curve.isInG1(signature.s);
        success &= this.curve.isInG1(signature.t);
        success &= this.curve.isInG1(signature.w);
        // Check that this is not the trivial credential (1, 1, 1, 1)
        success &= !this.curve.isIdentityG1(signature.r);
        // Verify that c2, s2 proves SPK{(sk): w = s^sk}(krd, appId)
        success &= signature.c2.equals(this.curve.hashModOrder(
                this.curve.point1ToBytes(signature.s.multiplyPoint(signature.s2)
                        .subtractPoint(signature.w.multiplyPoint(signature.c2))),
                this.curve.point1ToBytes(signature.s), this.curve.point1ToBytes(signature.w), appId.getBytes(),
                this.curve.hash(signature.krd)));
        // Verify credential
        success &= this.curve.pair(signature.r, pk.Y).equals(this.curve.pair(signature.s, this.curve.getG2()));
        success &= this.curve.pair(signature.t, this.curve.getG2())
                .equals(this.curve.pair(signature.r.clone().addPoint(signature.w), pk.X));
        // Perform revocation check
        if (revocationList != null) {
            for (BigInteger sk : revocationList) {
                success &= !signature.s.clone().multiplyPoint(sk).equals(signature.w);
            }
        }
        return success;
    }

    public boolean verifyWrt(byte[] message, byte[] session, EcDaaSignature signature, String appId,
            IssuerPublicKey pk, Set<BigInteger> revocationList) throws NoSuchAlgorithmException {
        BigInteger l = this.curve.hashModOrder(message);
        //ECPoint a  = this.curve.getG1().multiplyPoint(l);
        BigInteger h = this.curve.hashModOrder(session);
        //ECPoint r = a.multiplyPoint(h);
        boolean success = true;
        //    success &= (signature.r.getCoordinate().getX().getField().getCardinality() == r.getCoordinate().getX().getField().getCardinality());
        //    success &= (signature.r.getCoordinate().getY().getField().getCardinality() == r.getCoordinate().getY().getField().getCardinality());
        signature.w = signature.w.multiplyPoint(l);
        if (success) {
            return verify(signature, appId, pk, revocationList);
        } else
            return success;
    }

    /**
     * Turns a revocation list as a set of big integers into a JSON object
     * @param revocationList The revocation list as a Set<BigInteger>
     * @param curve The curve used
     * @return The revocation list as a JSON object
     */
    public static String revocationListToJson(Set<BigInteger> revocationList, BNCurve curve) {
        StringBuilder sb = new StringBuilder();
        Base64.Encoder encoder = Base64.getUrlEncoder();

        sb.append("{\"" + JSON_REVOCATION_LIST + "\":[");

        StringJoiner sj = new StringJoiner(",");
        for (BigInteger revoked : revocationList) {
            sj.add("{\"" + JSON_REVOCATION_LIST_ENTRY + "\":\""
                    + encoder.encodeToString(curve.bigIntegerToB(revoked)) + "\"}");
        }
        sb.append(sj.toString());
        sb.append("]}");

        return sb.toString();
    }

    /**
     * Turns a revocation list as JSON object into a set of big integers
     * @param json the revocation list as a JSON object
     * @param curve the curve used
     * @return the revocation list as a Set<BigInteger>
     */
    public static Set<BigInteger> revocationListFromJson(String json, BNCurve curve) {
        Base64.Decoder decoder = Base64.getUrlDecoder();

        JsonArray object = new JsonParser().parse(json).getAsJsonObject().getAsJsonArray(JSON_REVOCATION_LIST);
        Set<BigInteger> rl = new HashSet<BigInteger>(object.size());
        for (JsonElement element : object) {
            rl.add(curve.bigIntegerFromB(
                    decoder.decode(element.getAsJsonObject().get(JSON_REVOCATION_LIST_ENTRY).getAsString())));
        }
        return rl;
    }
}