/*
* The MIT License
*
* Copyright 2016 Ahseya.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package com.github.horrorho.inflatabledonkey.crypto;
import java.nio.ByteBuffer;
import static java.nio.charset.StandardCharsets.UTF_8;
import java.util.function.Supplier;
import javax.annotation.concurrent.Immutable;
import org.bouncycastle.crypto.Digest;
import org.bouncycastle.crypto.generators.KDFCounterBytesGenerator;
import org.bouncycastle.crypto.macs.HMac;
import org.bouncycastle.crypto.params.KDFCounterParameters;
import org.bouncycastle.util.encoders.Hex;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* NIST SP800-108 key derivation.
*
* @author Ahseya
*/
@Immutable
public final class NISTKDF {
private static final Logger logger = LoggerFactory.getLogger(NISTKDF.class);
private static final int R = 32; // counter length in bits
private NISTKDF() {
}
public static byte[]
ctrHMac(byte[] keyDerivationKey, String label, Supplier<Digest> digestSupplier, int keyLengthBytes) {
return ctrHMac(keyDerivationKey, label.getBytes(UTF_8), digestSupplier, keyLengthBytes);
}
// KDF in Counter Mode with an HMAC PRF
// TODO document exceptions
public static byte[]
ctrHMac(byte[] keyDerivationKey, byte[] label, Supplier<Digest> digestSupplier, int keyLengthBytes) {
logger.trace("<< ctrHMac() - keyDerivationKey: 0x{} label: {} digestSupplier: {} length: {}",
Hex.toHexString(keyDerivationKey), Hex.toHexString(label), digestSupplier, keyLengthBytes);
byte[] derivedKey = new byte[keyLengthBytes];
// fixedInputData = label || 0x00 || dkLen in bits as 4 bytes big endian
ByteBuffer buffer = ByteBuffer.allocate(label.length + 5);
buffer.put(label);
buffer.put((byte) 0);
buffer.putInt(keyLengthBytes * 8);
byte[] fixedInputData = buffer.array();
logger.debug("-- ctrHMac() - fixed input data: 0x{}", Hex.toHexString(fixedInputData));
HMac hMac = new HMac(digestSupplier.get());
KDFCounterBytesGenerator generator = new KDFCounterBytesGenerator(hMac);
generator.init(new KDFCounterParameters(keyDerivationKey, fixedInputData, R));
generator.generateBytes(derivedKey, 0, derivedKey.length);
logger.trace(">> ctrHMac() - derivedKey: 0x{}", Hex.toHexString(derivedKey));
return derivedKey;
}
}
// TODO test
