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c38a8aa699
1) Generate a Curve25519 identity key. 2) Use Curve25519 ephemerals and identities for v2 3DHE agreements. 3) Initiate v2 key exchange messages. 4) Accept v1 key exchange messages. 5) TOFU Curve25519 identities.
86 lines
3.0 KiB
Java
86 lines
3.0 KiB
Java
/**
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* Copyright (C) 2013 Open Whisper Systems
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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package org.whispersystems.textsecure.crypto.ecc;
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import org.whispersystems.textsecure.crypto.InvalidKeyException;
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import org.whispersystems.textsecure.crypto.protocol.CiphertextMessage;
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public class Curve {
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public static final int NIST_TYPE = 0x02;
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private static final int NIST_TYPE2 = 0x03;
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public static final int DJB_TYPE = 0x04;
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public static ECKeyPair generateKeyPairForType(int keyType) {
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if (keyType == DJB_TYPE) {
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return Curve25519.generateKeyPair();
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} else if (keyType == NIST_TYPE || keyType == NIST_TYPE2) {
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return CurveP256.generateKeyPair();
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} else {
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throw new AssertionError("Bad key type: " + keyType);
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}
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}
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public static ECKeyPair generateKeyPairForSession(int messageVersion) {
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if (messageVersion >= CiphertextMessage.CURVE25519_INTRODUCED_VERSION) {
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return generateKeyPairForType(DJB_TYPE);
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} else {
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return generateKeyPairForType(NIST_TYPE);
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}
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}
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public static ECPublicKey decodePoint(byte[] bytes, int offset)
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throws InvalidKeyException
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{
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int type = bytes[offset];
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if (type == DJB_TYPE) {
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return Curve25519.decodePoint(bytes, offset);
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} else if (type == NIST_TYPE || type == NIST_TYPE2) {
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return CurveP256.decodePoint(bytes, offset);
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} else {
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throw new InvalidKeyException("Unknown key type: " + type);
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}
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}
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public static ECPrivateKey decodePrivatePoint(int type, byte[] bytes) {
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if (type == DJB_TYPE) {
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return new DjbECPrivateKey(bytes);
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} else if (type == NIST_TYPE || type == NIST_TYPE2) {
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return CurveP256.decodePrivatePoint(bytes);
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} else {
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throw new AssertionError("Bad key type: " + type);
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}
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}
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public static byte[] calculateAgreement(ECPublicKey publicKey, ECPrivateKey privateKey)
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throws InvalidKeyException
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{
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if (publicKey.getType() != privateKey.getType()) {
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throw new InvalidKeyException("Public and private keys must be of the same type!");
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}
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if (publicKey.getType() == DJB_TYPE) {
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return Curve25519.calculateAgreement(publicKey, privateKey);
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} else if (publicKey.getType() == NIST_TYPE || publicKey.getType() == NIST_TYPE2) {
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return CurveP256.calculateAgreement(publicKey, privateKey);
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} else {
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throw new InvalidKeyException("Unknown type: " + publicKey.getType());
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}
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}
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}
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