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/*
This file is part of GNUnet.
(C) 2012, 2013 Christian Grothoff (and other contributing authors)
GNUnet is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published
by the Free Software Foundation; either version 3, or (at your
option) any later version.
GNUnet is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with GNUnet; see the file COPYING. If not, write to the
Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.
*/
package org.gnunet.voting;
import com.google.common.base.Optional;
import com.google.common.base.Preconditions;
import org.gnunet.util.AbsoluteTime;
import org.gnunet.util.Configuration;
import org.gnunet.util.crypto.EcdsaPrivateKey;
import org.gnunet.util.crypto.EcdsaPublicKey;
import org.gnunet.util.crypto.EcdsaSignature;
/**
* Group certificate. Attests to the fact that a voter (identified
* by a ECDSA public key) belongs to a group (given as string identifier) until a
* the an expiration date (given as timestamp).
*/
public class GroupCert {
private String group;
private EcdsaPublicKey member;
private EcdsaPublicKey signerPublicKey;
private AbsoluteTime expiration;
private EcdsaSignature signature;
private GroupCert() {
// do nothing, just make constructor private
}
public static GroupCert create(EcdsaPublicKey member, String group, EcdsaPrivateKey signerPrivateKey,
EcdsaPublicKey signerPublicKey, AbsoluteTime expiration) {
Preconditions.checkNotNull(member);
Preconditions.checkNotNull(group);
Preconditions.checkNotNull(signerPrivateKey);
Preconditions.checkNotNull(signerPublicKey);
Preconditions.checkNotNull(expiration);
GroupCert groupCert = new GroupCert();
groupCert.member = member;
groupCert.expiration = expiration;
groupCert.group = group;
groupCert.signerPublicKey = signerPublicKey;
String signData = "";
signData += member.toString();
signData += expiration.getSeconds();
signData += group;
signData += signerPublicKey;
groupCert.signature = signerPrivateKey.sign(signData.getBytes(), 0);
return groupCert;
}
public static GroupCert fromBallotConfig(Ballot ballot, Configuration cfg) {
GroupCert groupCert = new GroupCert();
Optional<String> optGroupSig = cfg.getValueString("vote", "GROUP_SIG");
Optional<Long> optGroupExp = cfg.getValueNumber("vote", "GROUP_EXPIRATION");
groupCert.member = ballot.voterPub;
groupCert.group = ballot.group;
if (!optGroupSig.isPresent()) {
throw new InvalidBallotException("missing group cert signature in ballot");
}
groupCert.signature = EcdsaSignature.fromString(optGroupSig.get());
if (groupCert.signature == null) {
throw new InvalidBallotException("invalid group cert signature in ballot");
}
if (!optGroupExp.isPresent()) {
throw new InvalidBallotException("missing or invalid group cert expiration in ballot");
}
groupCert.expiration = AbsoluteTime.fromSeconds(optGroupExp.get());
return groupCert;
}
public static GroupCert fromGroupCertConfig(Configuration cfg) {
GroupCert groupCert = new GroupCert();
Optional<String> optMember = cfg.getValueString("groupcert", "MEMBER");
Optional<String> optCa = cfg.getValueString("groupcert", "CA");
Optional<String> optSig = cfg.getValueString("groupcert", "SIG");
Optional<Long> optExpiration = cfg.getValueNumber("groupcert", "EXPIRATION");
Optional<String> optGroup = cfg.getValueString("groupcert", "GROUP");
if (!optMember.isPresent()) {
throw new InvalidGroupCertException("missing member key in group cert");
}
if (!optCa.isPresent()) {
throw new InvalidGroupCertException("missing CA in group cert");
}
if (!optSig.isPresent()) {
throw new InvalidGroupCertException("missing signature in group cert");
}
if (!optExpiration.isPresent()) {
throw new InvalidGroupCertException("missing expiration in group cert");
}
if (!optGroup.isPresent()) {
throw new InvalidGroupCertException("missing group identifier in group cert");
}
groupCert.group = optGroup.get();
groupCert.signature = EcdsaSignature.fromString(optSig.get());
if (null == groupCert.signature) {
throw new InvalidGroupCertException("invalid signature in group cert");
}
groupCert.expiration = AbsoluteTime.fromSeconds(optExpiration.get());
groupCert.signerPublicKey = EcdsaPublicKey.fromString(optCa.get());
if (null == groupCert.signerPublicKey) {
throw new InvalidGroupCertException("invalid CA in group cert");
}
groupCert.member = EcdsaPublicKey.fromString(optMember.get());
if (null == groupCert.member) {
throw new InvalidGroupCertException("invalid member in group cert");
}
return groupCert;
}
/**
* Encode the group certificate in a ballot configuration.
*
* @param cfg ballot configuration
*/
public void writeBallotConfig(Configuration cfg) {
cfg.setValueString("vote", "GROUP_SIG", signature.toString());
cfg.setValueNumber("vote", "GROUP_EXPIRATION", expiration.getSeconds());
}
/**
* Encode the group certificate in a group certificate config file.
*
* @param cfg group cert config file
*/
public void writeGroupCertConfig(Configuration cfg) {
cfg.setValueString("groupcert", "MEMBER", member.toString());
cfg.setValueString("groupcert", "CA", signerPublicKey.toString());
cfg.setValueString("groupcert", "SIG", signature.toString());
cfg.setValueNumber("groupcert", "EXPIRATION", expiration.getSeconds());
cfg.setValueString("groupcert", "GROUP", group);
}
public EcdsaPublicKey getMemberPublicKey() {
return member;
}
public AbsoluteTime getExpiration() {
return expiration;
}
public EcdsaSignature getSignature() {
return signature;
}
}
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