pemutilities.java

java 文件下载器。可自定义

// Decompiled by Jad v1.5.8e2. Copyright 2001 Pavel Kouznetsov.
// Jad home page: http://kpdus.tripod.com/jad.html
// Decompiler options: packimports(3) fieldsfirst ansi space 
// Source File Name:   PEMUtilities.java

package org.bouncycastle.openssl;

import java.io.IOException;
import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.spec.*;
import org.bouncycastle.crypto.PBEParametersGenerator;
import org.bouncycastle.crypto.generators.OpenSSLPBEParametersGenerator;
import org.bouncycastle.crypto.params.KeyParameter;

final class PEMUtilities
{

	PEMUtilities()
	{
	}

	static byte[] crypt(boolean encrypt, String provider, byte bytes[], char password[], String dekAlgName, byte iv[])
		throws IOException
	{
		java.security.spec.AlgorithmParameterSpec paramSpec;
		java.security.Key sKey;
		String transformation;
		paramSpec = new IvParameterSpec(iv);
		String blockMode = "CBC";
		String padding = "PKCS5Padding";
		if (dekAlgName.endsWith("-CFB"))
		{
			blockMode = "CFB";
			padding = "NoPadding";
		}
		if (dekAlgName.endsWith("-ECB") || "DES-EDE".equals(dekAlgName) || "DES-EDE3".equals(dekAlgName))
		{
			blockMode = "ECB";
			paramSpec = null;
		}
		if (dekAlgName.endsWith("-OFB"))
		{
			blockMode = "OFB";
			padding = "NoPadding";
		}
		String alg;
		if (dekAlgName.startsWith("DES-EDE"))
		{
			alg = "DESede";
			boolean des2 = !dekAlgName.startsWith("DES-EDE3");
			sKey = getKey(password, alg, 24, iv, des2);
		} else
		if (dekAlgName.startsWith("DES-"))
		{
			alg = "DES";
			sKey = getKey(password, alg, 8, iv);
		} else
		if (dekAlgName.startsWith("BF-"))
		{
			alg = "Blowfish";
			sKey = getKey(password, alg, 16, iv);
		} else
		if (dekAlgName.startsWith("RC2-"))
		{
			alg = "RC2";
			int keyBits = 128;
			if (dekAlgName.startsWith("RC2-40-"))
				keyBits = 40;
			else
			if (dekAlgName.startsWith("RC2-64-"))
				keyBits = 64;
			sKey = getKey(password, alg, keyBits / 8, iv);
			if (paramSpec == null)
				paramSpec = new RC2ParameterSpec(keyBits);
			else
				paramSpec = new RC2ParameterSpec(keyBits, iv);
		} else
		if (dekAlgName.startsWith("AES-"))
		{
			alg = "AES";
			byte salt[] = iv;
			if (salt.length > 8)
			{
				salt = new byte[8];
				System.arraycopy(iv, 0, salt, 0, 8);
			}
			int keyBits;
			if (dekAlgName.startsWith("AES-128-"))
				keyBits = 128;
			else
			if (dekAlgName.startsWith("AES-192-"))
				keyBits = 192;
			else
			if (dekAlgName.startsWith("AES-256-"))
				keyBits = 256;
			else
				throw new IOException("unknown AES encryption with private key");
			sKey = getKey(password, "AES", keyBits / 8, salt);
		} else
		{
			throw new IOException("unknown encryption with private key");
		}
		transformation = (new StringBuilder()).append(alg).append("/").append(blockMode).append("/").append(padding).toString();
		Cipher c;
		c = Cipher.getInstance(transformation, provider);
		int mode = encrypt ? 1 : 2;
		if (paramSpec == null)
			c.init(mode, sKey);
		else
			c.init(mode, sKey, paramSpec);
		return c.doFinal(bytes);
		Exception e;
		e;
		throw new IOException((new StringBuilder()).append("exception using cipher: ").append(e.toString()).toString());
	}

	private static SecretKey getKey(char password[], String algorithm, int keyLength, byte salt[])
		throws IOException
	{
		return getKey(password, algorithm, keyLength, salt, false);
	}

	private static SecretKey getKey(char password[], String algorithm, int keyLength, byte salt[], boolean des2)
		throws IOException
	{
		OpenSSLPBEParametersGenerator pGen = new OpenSSLPBEParametersGenerator();
		pGen.init(PBEParametersGenerator.PKCS5PasswordToBytes(password), salt);
		KeyParameter keyParam = (KeyParameter)pGen.generateDerivedParameters(keyLength * 8);
		byte key[] = keyParam.getKey();
		if (des2 && key.length >= 24)
			System.arraycopy(key, 0, key, 16, 8);
		return new SecretKeySpec(key, algorithm);
	}
}