org.jasypt.salt.StringFixedSaltGenerator Maven / Gradle / Ivy
/*
* =============================================================================
*
* Copyright (c) 2007-2010, The JASYPT team (http://www.jasypt.org)
*
* 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 org.jasypt.salt;
import java.io.UnsupportedEncodingException;
import org.jasypt.commons.CommonUtils;
import org.jasypt.exceptions.EncryptionInitializationException;
/**
*
* String based implementation of {@link FixedSaltGenerator}, that will
* always return the same salt. This salt is returned as bytes using the
* specified charset for conversion (UTF-8 by default).
*
*
* If the requested salt has a size in bytes smaller than the specified salt,
* the first n bytes are returned. If it is larger, an exception is thrown.
*
*
* This class is thread-safe.
*
*
* @since 1.9.2
*
* @author Daniel Fernández
*
*/
public class StringFixedSaltGenerator implements FixedSaltGenerator {
private static final String DEFAULT_CHARSET = "UTF-8";
private final String salt;
private final String charset;
private final byte[] saltBytes;
/**
* Creates a new instance of FixedStringSaltGenerator using
* the default charset.
*
* @param salt the specified salt.
*/
public StringFixedSaltGenerator(final String salt) {
this(salt, null);
}
/**
* Creates a new instance of FixedStringSaltGenerator
*
* @param salt the specified salt.
* @param charset the specified charset
*/
public StringFixedSaltGenerator(final String salt, final String charset) {
super();
CommonUtils.validateNotNull(salt, "Salt cannot be set null");
this.salt = salt;
this.charset = (charset != null? charset : DEFAULT_CHARSET);
try {
this.saltBytes = this.salt.getBytes(this.charset);
} catch (UnsupportedEncodingException e) {
throw new EncryptionInitializationException(
"Invalid charset specified: " + this.charset);
}
}
/**
* Return salt with the specified byte length.
*
* @param lengthBytes length in bytes.
* @return the generated salt.
*/
public byte[] generateSalt(final int lengthBytes) {
if (this.saltBytes.length < lengthBytes) {
throw new EncryptionInitializationException(
"Requested salt larger than set");
}
final byte[] generatedSalt = new byte[lengthBytes];
System.arraycopy(this.saltBytes, 0, generatedSalt, 0, lengthBytes);
return generatedSalt;
}
/**
* As this salt generator provides a fixed salt, its inclusion
* unencrypted in encryption results
* is not necessary, and in fact not desirable (so that it remains hidden).
*
* @return false
*/
public boolean includePlainSaltInEncryptionResults() {
return false;
}
}