62 lines
2.1 KiB
Java
62 lines
2.1 KiB
Java
/*
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* Copyright 2018 Paul Schaub.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package org.pgpainless.util;
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import java.security.NoSuchAlgorithmException;
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import org.bouncycastle.asn1.ASN1ObjectIdentifier;
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import org.bouncycastle.bcpg.ECPublicBCPGKey;
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import org.bouncycastle.openpgp.PGPPublicKey;
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public final class BCUtil {
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private BCUtil() {
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}
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/**
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* Utility method to get the bit strength of OpenPGP keys.
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* Bouncycastle is lacking support for some keys (eg. EdDSA, X25519), so this method
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* manually derives the bit strength from the keys curves OID.
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*
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* @param key key
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* @return bit strength
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*/
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public static int getBitStrength(PGPPublicKey key) throws NoSuchAlgorithmException {
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int bitStrength = key.getBitStrength();
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if (bitStrength == -1) {
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// BC's PGPPublicKey.getBitStrength() does fail for some keys (EdDSA, X25519)
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// therefore we manually set the bit strength.
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// see https://github.com/bcgit/bc-java/issues/972
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ASN1ObjectIdentifier oid = ((ECPublicBCPGKey) key.getPublicKeyPacket().getKey()).getCurveOID();
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if (oid.getId().equals("1.3.6.1.4.1.11591.15.1")) {
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// ed25519 is 256 bits
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bitStrength = 256;
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} else if (oid.getId().equals("1.3.6.1.4.1.3029.1.5.1")) {
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// curvey25519 is 256 bits
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bitStrength = 256;
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} else {
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throw new NoSuchAlgorithmException("Unknown curve: " + oid.getId());
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}
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}
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return bitStrength;
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}
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}
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