org.jolokia.jvmagent.security.PKCS1Util Maven / Gradle / Ivy
package org.jolokia.jvmagent.security;/*
*
* Copyright 2015
*
* 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.
*/
import java.io.*;
import java.math.BigInteger;
import java.security.spec.RSAPrivateCrtKeySpec;
/**
* This code is inspired and taken over from net.auth.core:oauth
* (albeit in a highly stripped variation):
*
* Source is from http://oauth.googlecode.com/svn/code/java/ which is licensed
* under the APL (http://oauth.googlecode.com/svn/code/java/LICENSE.txt)
*
* All credits go to the original author (zhang)
*
* @author roland
* @since 30/09/15
*/
class PKCS1Util {
private PKCS1Util() {
}
public static RSAPrivateCrtKeySpec decodePKCS1(byte[] keyBytes) throws IOException {
DerParser parser = new DerParser(keyBytes);
Asn1Object sequence = parser.read();
sequence.validateSequence();
parser = new DerParser(sequence.getValue());
parser.read();
return new RSAPrivateCrtKeySpec(next(parser), next(parser),
next(parser), next(parser),
next(parser), next(parser),
next(parser), next(parser));
}
// ==========================================================================================
private static BigInteger next(DerParser parser) throws IOException {
return parser.read().getInteger();
}
static class DerParser {
private InputStream in;
DerParser(byte[] bytes) throws IOException {
this.in = new ByteArrayInputStream(bytes);
}
Asn1Object read() throws IOException {
int tag = in.read();
if (tag == -1) {
throw new IOException("Invalid DER: stream too short, missing tag");
}
int length = getLength();
byte[] value = new byte[length];
if (in.read(value) < length) {
throw new IOException("Invalid DER: stream too short, missing value");
}
return new Asn1Object(tag, value);
}
private int getLength() throws IOException {
int i = in.read();
if (i == -1) {
throw new IOException("Invalid DER: length missing");
}
if ((i & ~0x7F) == 0) {
return i;
}
int num = i & 0x7F;
if (i >= 0xFF || num > 4) {
throw new IOException("Invalid DER: length field too big ("
+ i + ")");
}
byte[] bytes = new byte[num];
if (in.read(bytes) < num) {
throw new IOException("Invalid DER: length too short");
}
return new BigInteger(1, bytes).intValue();
}
}
static class Asn1Object {
private final int type;
private final byte[] value;
private final int tag;
public Asn1Object(int tag, byte[] value) {
this.tag = tag;
this.type = tag & 0x1F;
this.value = value;
}
public byte[] getValue() {
return value;
}
BigInteger getInteger() throws IOException {
if (type != 0x02) {
throw new IOException("Invalid DER: object is not integer"); //$NON-NLS-1$
}
return new BigInteger(value);
}
void validateSequence() throws IOException {
if (type != 0x10) {
throw new IOException("Invalid DER: not a sequence");
}
if ((tag & 0x20) != 0x20) {
throw new IOException("Invalid DER: can't parse primitive entity");
}
}
}
}