net.shibboleth.utilities.java.support.security.RandomIdentifierGenerationStrategy Maven / Gradle / Ivy
/*
* Licensed to the University Corporation for Advanced Internet Development,
* Inc. (UCAID) under one or more contributor license agreements. See the
* NOTICE file distributed with this work for additional information regarding
* copyright ownership. The UCAID licenses this file to You 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 net.shibboleth.utilities.java.support.security;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.util.Random;
import javax.annotation.Nonnull;
import net.shibboleth.utilities.java.support.logic.Constraint;
import org.apache.commons.codec.BinaryEncoder;
import org.apache.commons.codec.EncoderException;
import org.apache.commons.codec.binary.Hex;
import org.apache.commons.codec.binary.StringUtils;
/**
* Generates a random number of bytes via a {@link Random} source and encodes them into a string using a
* {@link BinaryEncoder} ({@link Hex} by default).
*/
public class RandomIdentifierGenerationStrategy implements IdentifierGenerationStrategy {
/** Random number generator. */
private final Random random;
/** Number of random bytes in the identifier. */
private final int sizeOfIdentifier;
/** Encoder used to convert the random bytes in to a string. */
private final BinaryEncoder encoder;
/**
* Constructor. Initializes the random number source to a new {@link SecureRandom}, size of identifier is set to 16
* bytes, and the encoder is set to a {@link Hex}.
*/
public RandomIdentifierGenerationStrategy() {
try {
random = SecureRandom.getInstance("SHA1PRNG");
sizeOfIdentifier = 16;
encoder = new Hex();
} catch (final NoSuchAlgorithmException e) {
throw new RuntimeException("SHA1PRNG is required to be supported by the JVM but is not", e);
}
}
/**
* Constructor. Initializes the random number source to a new {@link SecureRandom} and the encoder is set to a
* {@link Hex}.
*
* @param identifierSize number of random bytes in identifier
*/
public RandomIdentifierGenerationStrategy(final int identifierSize) {
try {
random = SecureRandom.getInstance("SHA1PRNG");
sizeOfIdentifier =
(int) Constraint.isGreaterThan(0, identifierSize,
"Number of bytes in the identifier must be greater than 0");
encoder = new Hex();
} catch (final NoSuchAlgorithmException e) {
throw new RuntimeException("SHA1PRNG is required to be supported by the JVM but is not", e);
}
}
/**
* Constructor.
*
* @param source source of random bytes
* @param identifierSize number of random bytes in the identifier
* @param identifierEncoder encoder used to convert random bytes to string identifier
*/
public RandomIdentifierGenerationStrategy(@Nonnull final Random source, final int identifierSize,
@Nonnull final BinaryEncoder identifierEncoder) {
random = Constraint.isNotNull(source, "Random number source can not be null");
sizeOfIdentifier =
(int) Constraint.isGreaterThan(0, identifierSize,
"Number of bytes in the identifier must be greater than 0");
encoder = Constraint.isNotNull(identifierEncoder, "Identifier is encoder can not be null");
}
/** {@inheritDoc} */
@Nonnull public String generateIdentifier() {
return generateIdentifier(true);
}
/** {@inheritDoc} */
public String generateIdentifier(final boolean xmlSafe) {
final byte[] buf = new byte[sizeOfIdentifier];
random.nextBytes(buf);
try {
if (xmlSafe) {
return "_" + StringUtils.newStringUsAscii(encoder.encode(buf));
} else {
return StringUtils.newStringUsAscii(encoder.encode(buf));
}
} catch (final EncoderException e) {
throw new RuntimeException(e);
}
}
}