open-keychain/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/securitytoken/ECKeyFormat.java
2017-05-25 15:42:27 +02:00

113 lines
4.1 KiB
Java

/*
* Copyright (C) 2016 Nikita Mikhailov <nikita.s.mikhailov@gmail.com>
* Copyright (C) 2016-2017 Arnaud Fontaine
*
* This program 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 of the License, or
* (at your option) any later version.
*
* This program 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 this program. If not, see <http://www.gnu.org/licenses/>.
*/
package org.sufficientlysecure.keychain.securitytoken;
import org.bouncycastle.asn1.ASN1ObjectIdentifier;
import org.bouncycastle.asn1.nist.NISTNamedCurves;
import org.bouncycastle.asn1.x9.X9ECParameters;
import org.bouncycastle.bcpg.sig.KeyFlags;
import org.bouncycastle.math.ec.ECCurve;
import org.sufficientlysecure.keychain.service.SaveKeyringParcel;
import org.sufficientlysecure.keychain.service.SaveKeyringParcel.SubkeyAdd;
// 4.3.3.6 Algorithm Attributes
public class ECKeyFormat extends KeyFormat {
private final ECAlgorithmFormat mECAlgorithmFormat;
private final ASN1ObjectIdentifier mECCurveOID;
public ECKeyFormat(final ASN1ObjectIdentifier ecCurveOid,
final ECAlgorithmFormat ecAlgorithmFormat) {
super(KeyFormatType.ECKeyFormatType);
mECAlgorithmFormat = ecAlgorithmFormat;
mECCurveOID = ecCurveOid;
}
public ECKeyFormat.ECAlgorithmFormat getAlgorithmFormat() {
return mECAlgorithmFormat;
}
public ASN1ObjectIdentifier getCurveOID() {
return mECCurveOID;
}
public enum ECAlgorithmFormat {
ECDH((byte) 18, true, false),
ECDH_WITH_PUBKEY((byte) 18, true, true),
ECDSA((byte) 19, false, false),
ECDSA_WITH_PUBKEY((byte) 19, false, true);
private final byte mValue;
private final boolean mIsECDH;
private final boolean mWithPubkey;
ECAlgorithmFormat(final byte value, final boolean isECDH, final boolean withPubkey) {
mValue = value;
mIsECDH = isECDH;
mWithPubkey = withPubkey;
}
public static ECKeyFormat.ECAlgorithmFormat from(final byte bFirst, final byte bLast) {
for (ECKeyFormat.ECAlgorithmFormat format : values()) {
if (format.mValue == bFirst && ((bLast == (byte) 0xff) == format.isWithPubkey())) {
return format;
}
}
return null;
}
public final byte getValue() {
return mValue;
}
public final boolean isECDH() {
return mIsECDH;
}
public final boolean isWithPubkey() {
return mWithPubkey;
}
}
public void addToSaveKeyringParcel(SaveKeyringParcel.Builder builder, int keyFlags) {
final X9ECParameters params = NISTNamedCurves.getByOID(mECCurveOID);
final ECCurve curve = params.getCurve();
SaveKeyringParcel.Algorithm algo = SaveKeyringParcel.Algorithm.ECDSA;
if (((keyFlags & KeyFlags.ENCRYPT_COMMS) == KeyFlags.ENCRYPT_COMMS)
|| ((keyFlags & KeyFlags.ENCRYPT_STORAGE) == KeyFlags.ENCRYPT_STORAGE)) {
algo = SaveKeyringParcel.Algorithm.ECDH;
}
SaveKeyringParcel.Curve scurve;
if (mECCurveOID.equals(NISTNamedCurves.getOID("P-256"))) {
scurve = SaveKeyringParcel.Curve.NIST_P256;
} else if (mECCurveOID.equals(NISTNamedCurves.getOID("P-384"))) {
scurve = SaveKeyringParcel.Curve.NIST_P384;
} else if (mECCurveOID.equals(NISTNamedCurves.getOID("P-521"))) {
scurve = SaveKeyringParcel.Curve.NIST_P521;
} else {
throw new IllegalArgumentException("Unsupported curve " + mECCurveOID);
}
builder.addSubkeyAdd(SubkeyAdd.createSubkeyAdd(algo, curve.getFieldSize(), scurve, keyFlags, 0L));
}
}