io.fusionauth.jwks.JWKUtils Maven / Gradle / Ivy
/*
* Copyright (c) 2020, FusionAuth, All Rights Reserved
*
* 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 io.fusionauth.jwks;
import java.math.BigInteger;
import java.util.Arrays;
import java.util.Base64;
/**
* @author Daniel DeGroff
*/
public class JWKUtils {
/**
* Decode an un-signed integer from a String to a BigInteger object.
*
* @param encoded the encoded integer
* @return a BigInteger representation of the encoded value.
*/
public static BigInteger base64DecodeUint(String encoded) {
byte[] bytes = Base64.getUrlDecoder().decode(encoded);
if (bytes.length % 8 == 0 && bytes[0] != 0) {
byte[] copy = new byte[bytes.length + 1];
copy[0] = 0;
System.arraycopy(bytes, 0, copy, 1, bytes.length);
return new BigInteger(copy);
}
return new BigInteger(bytes);
}
/**
* Encode an un-signed integer from a BigInteger to a String.
*
* @param value the integer value
* @return a Base64 encoded value of the un-signed integer.
*/
public static String base64EncodeUint(BigInteger value) {
return base64EncodeUint(value, -1);
}
/**
* Encode an un-signed integer from a BigInteger to a String.
*
* @param value the integer value
* @param minimumLength the minimum length of the returned value. A value of -1 indicates there is no minimum.
* @return a Base64 encoded value of the un-signed integer.
*/
public static String base64EncodeUint(BigInteger value, int minimumLength) {
if (value.signum() < 0) {
throw new JSONWebKeyBuilderException("Illegal parameter, cannot encode a negative number.", new IllegalArgumentException());
}
byte[] bytes = value.toByteArray();
if ((value.bitLength() % 8 == 0) && (bytes[0] == 0) && bytes.length > 1) {
bytes = Arrays.copyOfRange(bytes, 1, bytes.length);
}
if (minimumLength != -1) {
if (bytes.length < minimumLength) {
byte[] buf = new byte[minimumLength];
System.arraycopy(bytes, 0, buf, (minimumLength - bytes.length), bytes.length);
bytes = buf;
}
}
return Base64.getUrlEncoder().withoutPadding().encodeToString(bytes);
}
}