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/*
* Copyright (C) 2012 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.android.org.conscrypt;
import java.math.BigInteger;
import java.security.InvalidAlgorithmParameterException;
import java.security.InvalidParameterException;
import java.security.spec.ECField;
import java.security.spec.ECFieldF2m;
import java.security.spec.ECFieldFp;
import java.security.spec.ECParameterSpec;
import java.security.spec.ECPoint;
import java.security.spec.EllipticCurve;
public final class OpenSSLECGroupContext {
private final long groupCtx;
public OpenSSLECGroupContext(long groupCtx) {
this.groupCtx = groupCtx;
}
public static OpenSSLECGroupContext getCurveByName(String curveName) {
// Workaround for OpenSSL not supporting SECG names for NIST P-192 and P-256
// (aka ANSI X9.62 prime192v1 and prime256v1) curve names.
if ("secp256r1".equals(curveName)) {
curveName = "prime256v1";
} else if ("secp192r1".equals(curveName)) {
curveName = "prime192v1";
}
final long ctx = NativeCrypto.EC_GROUP_new_by_curve_name(curveName);
if (ctx == 0) {
return null;
}
NativeCrypto.EC_GROUP_set_point_conversion_form(ctx,
NativeCrypto.POINT_CONVERSION_UNCOMPRESSED);
NativeCrypto.EC_GROUP_set_asn1_flag(ctx, NativeCrypto.OPENSSL_EC_NAMED_CURVE);
return new OpenSSLECGroupContext(ctx);
}
public static OpenSSLECGroupContext getInstance(int type, BigInteger p, BigInteger a,
BigInteger b, BigInteger x, BigInteger y, BigInteger n, BigInteger h) {
final long ctx = NativeCrypto.EC_GROUP_new_curve(type, p.toByteArray(), a.toByteArray(),
b.toByteArray());
if (ctx == 0) {
return null;
}
NativeCrypto.EC_GROUP_set_point_conversion_form(ctx,
NativeCrypto.POINT_CONVERSION_UNCOMPRESSED);
OpenSSLECGroupContext group = new OpenSSLECGroupContext(ctx);
OpenSSLECPointContext generator = new OpenSSLECPointContext(group,
NativeCrypto.EC_POINT_new(ctx));
NativeCrypto.EC_POINT_set_affine_coordinates(ctx, generator.getContext(),
x.toByteArray(), y.toByteArray());
NativeCrypto.EC_GROUP_set_generator(ctx, generator.getContext(), n.toByteArray(),
h.toByteArray());
return group;
}
@Override
protected void finalize() throws Throwable {
try {
if (groupCtx != 0) {
NativeCrypto.EC_GROUP_clear_free(groupCtx);
}
} finally {
super.finalize();
}
}
@Override
public boolean equals(Object o) {
if (!(o instanceof OpenSSLECGroupContext)) {
return false;
}
final OpenSSLECGroupContext other = (OpenSSLECGroupContext) o;
return NativeCrypto.EC_GROUP_cmp(groupCtx, other.groupCtx);
}
@Override
public int hashCode() {
// TODO Auto-generated method stub
return super.hashCode();
}
public long getContext() {
return groupCtx;
}
public static OpenSSLECGroupContext getInstance(ECParameterSpec params)
throws InvalidAlgorithmParameterException {
final String curveName = params.getCurveName();
if (curveName != null) {
return OpenSSLECGroupContext.getCurveByName(curveName);
}
final EllipticCurve curve = params.getCurve();
final ECField field = curve.getField();
final int type;
final BigInteger p;
if (field instanceof ECFieldFp) {
type = NativeCrypto.EC_CURVE_GFP;
p = ((ECFieldFp) field).getP();
} else if (field instanceof ECFieldF2m) {
type = NativeCrypto.EC_CURVE_GF2M;
p = ((ECFieldF2m) field).getReductionPolynomial();
} else {
throw new InvalidParameterException("unhandled field class "
+ field.getClass().getName());
}
final ECPoint generator = params.getGenerator();
return OpenSSLECGroupContext.getInstance(type, p, curve.getA(), curve.getB(),
generator.getAffineX(), generator.getAffineY(), params.getOrder(),
BigInteger.valueOf(params.getCofactor()));
}
public ECParameterSpec getECParameterSpec() {
final String curveName = NativeCrypto.EC_GROUP_get_curve_name(groupCtx);
final byte[][] curveParams = NativeCrypto.EC_GROUP_get_curve(groupCtx);
final BigInteger p = new BigInteger(curveParams[0]);
final BigInteger a = new BigInteger(curveParams[1]);
final BigInteger b = new BigInteger(curveParams[2]);
final ECField field;
final int type = NativeCrypto.get_EC_GROUP_type(groupCtx);
if (type == NativeCrypto.EC_CURVE_GFP) {
field = new ECFieldFp(p);
} else if (type == NativeCrypto.EC_CURVE_GF2M) {
field = new ECFieldF2m(p.bitLength() - 1, p);
} else {
throw new RuntimeException("unknown curve type " + type);
}
final EllipticCurve curve = new EllipticCurve(field, a, b);
final OpenSSLECPointContext generatorCtx = new OpenSSLECPointContext(this,
NativeCrypto.EC_GROUP_get_generator(groupCtx));
final ECPoint generator = generatorCtx.getECPoint();
final BigInteger order = new BigInteger(NativeCrypto.EC_GROUP_get_order(groupCtx));
final BigInteger cofactor = new BigInteger(NativeCrypto.EC_GROUP_get_cofactor(groupCtx));
return new ECParameterSpec(curve, generator, order, cofactor.intValue(), curveName);
}
}
