Java tutorial
/** * The MIT License * * Copyright (C) 2015 Asterios Raptis * * 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 de.alpharogroup.crypto.key; import java.security.PublicKey; import java.security.interfaces.DSAPublicKey; import java.security.interfaces.ECPublicKey; import java.security.interfaces.RSAPublicKey; import org.apache.commons.codec.binary.Base64; import de.alpharogroup.crypto.hex.HexExtensions; import lombok.experimental.UtilityClass; /** * The class {@link PublicKeyExtensions}. */ @UtilityClass public class PublicKeyExtensions { /** * Gets the key length of the given {@link PublicKey}. * * @param publicKey * the public key * @return the key length */ public static int getKeyLength(final PublicKey publicKey) { int length = -1; if (publicKey == null) { return length; } if (publicKey instanceof RSAPublicKey) { length = ((RSAPublicKey) publicKey).getModulus().bitLength(); } if (publicKey instanceof DSAPublicKey) { length = ((DSAPublicKey) publicKey).getParams().getP().bitLength(); } if (publicKey instanceof ECPublicKey) { length = ((ECPublicKey) publicKey).getParams().getCurve().getField().getFieldSize(); } return length; } /** * Transform the given {@link PublicKey} to a hexadecimal {@link String} value. * * @param publicKey * the public key * @return the new hexadecimal {@link String} value. */ public static String toHexString(final PublicKey publicKey) { return toHexString(publicKey, true); } /** * Transform the given {@link PublicKey} to a base64 encoded {@link String} value. * * @param publicKey * the public key * @return the base64 encoded {@link String} value. */ public static String toBase64(final PublicKey publicKey) { final byte[] encoded = publicKey.getEncoded(); final String publicKeyAsBase64String = Base64.encodeBase64String(encoded); return publicKeyAsBase64String; } /** * Transform the given {@link PublicKey} to a hexadecimal {@link String} value. * * @param publicKey * the public key * @param lowerCase * the flag if the result shell be transform in lower case. If true the result is * @return the new hexadecimal {@link String} value. */ public static String toHexString(final PublicKey publicKey, final boolean lowerCase) { final String hexString = HexExtensions.toHexString(publicKey.getEncoded(), lowerCase); return hexString; } }