标签: RSA

Java RSA研究

前几天我做了PHP RSA的测试,想想Java来做RSA应该更简单,就在网上搜了一下Java RSA,发现资料是有一些,但却不是很完整,也不是很严谨,都是转来转去,看来还是自己要测试一下,两个文件RSAUtil.java和EncryptException.java,注意,JDK里没有RSA的provider,所以我们要用第三方的provider,在http://www.bouncycastle.org/下载最新的包,加入工程。

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import javax.crypto.Cipher;
import java.security.*;
import java.security.spec.RSAPublicKeySpec;
import java.security.spec.RSAPrivateKeySpec;
import java.security.spec.InvalidKeySpecException;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.io.*;
import java.math.BigInteger;
 
public class RSAUtil {
 
    /**
     *   * 生成密钥对
     *   * @return KeyPair
     *   * @throws EncryptException
     */
    public static KeyPair generateKeyPair() throws EncryptException {
        try {
            KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance("RSA",
                    new org.bouncycastle.jce.provider.BouncyCastleProvider());
            final int KEY_SIZE = 1024;//没什么好说的了,这个值关系到块加密的大小,可以更改,但是不要太大,否则效率会低
            keyPairGen.initialize(KEY_SIZE, new SecureRandom());
            KeyPair keyPair = keyPairGen.genKeyPair();
            return keyPair;
        } catch (Exception e) {
            throw new EncryptException(e.getMessage());
        }
    }
 
    /**
     *   * 生成公钥
     *   * @param modulus
     *   * @param publicExponent
     *   * @return RSAPublicKey
     *   * @throws EncryptException
     */
    public static RSAPublicKey generateRSAPublicKey(byte[] modulus, byte[] publicExponent) throws EncryptException {
        KeyFactory keyFac = null;
        try {
            keyFac = KeyFactory.getInstance("RSA", new org.bouncycastle.jce.provider.BouncyCastleProvider());
        } catch (NoSuchAlgorithmException ex) {
            throw new EncryptException(ex.getMessage());
        }
 
        RSAPublicKeySpec pubKeySpec = new RSAPublicKeySpec(new BigInteger(modulus), new BigInteger(publicExponent));
        try {
            return (RSAPublicKey) keyFac.generatePublic(pubKeySpec);
        } catch (InvalidKeySpecException ex) {
            throw new EncryptException(ex.getMessage());
        }
    }
 
    /**
     *   * 生成私钥
     *   * @param modulus
     *   * @param privateExponent
     *   * @return RSAPrivateKey
     *   * @throws EncryptException
     */
    public static RSAPrivateKey generateRSAPrivateKey(byte[] modulus, byte[] privateExponent) throws EncryptException {
        KeyFactory keyFac = null;
        try {
            keyFac = KeyFactory.getInstance("RSA", new org.bouncycastle.jce.provider.BouncyCastleProvider());
        } catch (NoSuchAlgorithmException ex) {
            throw new EncryptException(ex.getMessage());
        }
 
        RSAPrivateKeySpec priKeySpec = new RSAPrivateKeySpec(new BigInteger(modulus), new BigInteger(privateExponent));
        try {
            return (RSAPrivateKey) keyFac.generatePrivate(priKeySpec);
        } catch (InvalidKeySpecException ex) {
            throw new EncryptException(ex.getMessage());
        }
    }
 
    /**
     *   * 加密
     *   * @param key 加密的密钥
     *   * @param data 待加密的明文数据
     *   * @return 加密后的数据
     *   * @throws EncryptException
     */
    public static byte[] encrypt(Key key, byte[] data) throws EncryptException {
        try {
            Cipher cipher = Cipher.getInstance("RSA", new org.bouncycastle.jce.provider.BouncyCastleProvider());
            cipher.init(Cipher.ENCRYPT_MODE, key);
            int blockSize = cipher.getBlockSize();//获得加密块大小,如:加密前数据为128个byte,而key_size=1024 加密块大小为127 byte,加密后为128个byte;因此共有2个加密块,第一个127 byte第二个为1个byte
            int outputSize = cipher.getOutputSize(data.length);//获得加密块加密后块大小
            int leavedSize = data.length % blockSize;
            int blocksSize = leavedSize != 0 ? data.length / blockSize + 1 : data.length / blockSize;
            byte[] raw = new byte[outputSize * blocksSize];
            int i = 0;
            while (data.length - i * blockSize > 0) {
                if (data.length - i * blockSize > blockSize)
                    cipher.doFinal(data, i * blockSize, blockSize, raw, i * outputSize);
                else
                    cipher.doFinal(data, i * blockSize, data.length - i * blockSize, raw, i * outputSize);
//这里面doUpdate方法不可用,查看源代码后发现每次doUpdate后并没有什么实际动作除了把byte[]放到ByteArrayOutputStream中,而最后doFinal的时候才将所有的byte[]进行加密,可是到了此时加密块大小很可能已经超出了OutputSize所以只好用dofinal方法。
 
                i++;
            }
            return raw;
        } catch (Exception e) {
            throw new EncryptException(e.getMessage());
        }
    }
 
 
 
    /**
     *   * 解密
     *   * @param key 解密的密钥
     *   * @param raw 已经加密的数据
     *   * @return 解密后的明文
     *   * @throws EncryptException
     */
    public static byte[] decrypt(Key key, byte[] raw) throws EncryptException {
        try {
            Cipher cipher = Cipher.getInstance("RSA", new org.bouncycastle.jce.provider.BouncyCastleProvider());
            cipher.init(cipher.DECRYPT_MODE, key);
            int blockSize = cipher.getBlockSize();
            ByteArrayOutputStream bout = new ByteArrayOutputStream(64);
            int j = 0;
 
            while (raw.length - j * blockSize > 0) {
                bout.write(cipher.doFinal(raw, j * blockSize, blockSize));
                j++;
            }
            return bout.toByteArray();
        } catch (Exception e) {
            throw new EncryptException(e.getMessage());
        }
    }
 
    public static String byte2hex(byte[] b) {
        String hs = "";
        String stmp = "";
        for (int i = 0; i < b.length; i++) {
            stmp = Integer.toHexString(b[i] & 0xFF);
            if (stmp.length() == 1) {
                hs += "0" + stmp;
            } else {
                hs += stmp;
            }
        }
        //return hs;
        return hs.toUpperCase();
    }
 
 
    public static byte[] hex2byte(String hex) throws IllegalArgumentException {
        if (hex.length() % 2 != 0) {
            throw new IllegalArgumentException();
        }
        char[] arr = hex.toCharArray();
        byte[] b = new byte[hex.length() / 2];
        for (int i = 0, j = 0, l = hex.length(); i < l; i++, j++) {
            String swap = "" + arr[i++] + arr[i];
            int byteint = Integer.parseInt(swap, 16) & 0xFF;
            b[j] = new Integer(byteint).byteValue();
        }
        return b;
    }
 
    /**
     *   *
     *   * @param args
     *   * @throws Exception
     */
    public static void main(String[] args) throws Exception {
 
        byte[] orgData = "test".getBytes();
        KeyPair keyPair = RSAUtil.generateKeyPair();
        RSAPublicKey pubKey = (RSAPublicKey) keyPair.getPublic();
        RSAPrivateKey priKey = (RSAPrivateKey) keyPair.getPrivate();
 
        byte[] pubModBytes = pubKey.getModulus().toByteArray();
        System.out.println("PubKey Modulus:"+new BigInteger(pubModBytes).toString(16));
        byte[] pubPubExpBytes = pubKey.getPublicExponent().toByteArray();
        System.out.println("publicExponent:"+new BigInteger(pubPubExpBytes).toString(16));
        byte[] priModBytes = priKey.getModulus().toByteArray();
        byte[] priPriExpBytes = priKey.getPrivateExponent().toByteArray();
        RSAPublicKey recoveryPubKey = RSAUtil.generateRSAPublicKey(pubModBytes, pubPubExpBytes);
        RSAPrivateKey recoveryPriKey = RSAUtil.generateRSAPrivateKey(priModBytes, priPriExpBytes);
 
        byte[] raw = RSAUtil.encrypt(priKey, orgData);
        System.out.println("Encrypt:"+byte2hex(raw));
        byte[] data = RSAUtil.decrypt(recoveryPubKey, raw);
        System.out.println("Decrypt:"+new String(data));
 
    }
 
}
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public class EncryptException extends Exception {
 
    public EncryptException() {
        super();
    }
 
    public EncryptException(String message) {
        super(message);
    }
 
    public EncryptException(String message, Throwable cause) {
        super(message, cause);
    }
 
    public EncryptException(Throwable cause) {
        super(cause);
    }
 
}

我们看一下运行结果:

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PubKey Modulus:a907de8b5789b1df66c8a4ea90f99c9b00bbad520d487a7e218cd1ee2a1cafcaff2dd03a70cc61d8ccdfe0557b9132dd163a5a6c287d94790fc8b573a154ba0cd799e2cc73fc44c03083274760664125cafc33c647c44df300968665b6dbc9e553c59f8180de0ded3ae2163aab499c1ec0688ed7468fb816cdf05db501cbba19
publicExponent:10001
Encrypt:71521BBA91D871AAA8FF99D7E9D6E44DAE6218FAFDC07CE7C34ABACC1357854BF8F5D94F17FD106346B0916CC81A85B7031F9421810F1E5A568EE408E6DFDB219201CB1DE2AF259A516F3B930130D6AD4FFCB26072EB2BD9CFC11CA727B181A640311BC3023B2D1E54EBC52454C669389C24D0F7AD316B0B24257D53384E1446
Decrypt:test

使用已有的Modulus加密的话

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String modulus = "D192471B8699640F931FE6F4FACC3E990B894F894CEA5BEE0DCBD7A4B76752F7345CF9B5F1271001B724F7A0ABF0A6E911E309536F4BE4749E92DCC531B8E36B95969D206649C9DD2371B413A8DFD9B92569660B1499A5CD310B86A8FDE24988E456897A416D2E7B0B649F0714F322C57EF92563B21A448D1072FF3806C34C75";
byte[] b_modulus = new BigInteger(modulus,16).toByteArray();
String publicExponent = "10001";
byte[] b_publicExponent = new BigInteger(publicExponent,16).toByteArray();
String text = "test";
RSAPublicKey recoveryPubKey = RSAUtil.generateRSAPublicKey(b_modulus, b_publicExponent);        
byte[] ss = RSAUtil.encrypt(recoveryPubKey,text.getBytes());
System.out.println(byte2hex(ss));

PHP RSA研究

最近研究了一下QQ邮箱的登录过程,发现QQ邮箱登录比较严谨,加了一些小技巧,其中一点就是用JavaScript对用户的密码做了一下RSA的加密,在它的登录页面里有一段

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var PublicKey = "CF87D7B4C864F4842F1D337491A48FFF54B73A17300E8E42FA365420393AC0346AE55D8AFAD975DFA175FAF0106CBA81AF1DDE4ACEC284DAC6ED9A0D8FEB1CC070733C58213EFFED46529C54CEA06D774E3CC7E073346AEBD6C66FC973F299EB74738E400B22B1E7CDC54E71AED059D228DFEB5B29C530FF341502AE56DDCFE9";
var RSA = new RSAKey();
RSA.setPublic(PublicKey, "10001");
var Res = RSA.encrypt(document.form1.pp.value + '\n' + document.form1.ts.value + '\n');
if (Res)
{
document.form1.p.value = hex2b64(Res);
}

再看看RSAKey的相关源码,应该是在http://m367.mail.qq.com/zh_CN/htmledition/js/safeauth.js里,看了一下还是蛮复杂的,我就在Google上搜一下有没有相关的资料,找到了这个网站《BigIntegers and RSA in JavaScript》,看了一下他们的代码,和QQ里的基本一样嘛,估计QQ也是用了人家的代码,这篇文章里有密钥对的生成、加密解密的测试页面,由此推断QQ代码里的PublicKey,应该是密钥对的modulus(也可以理解为公钥吧),并且QQ用的是1024位的密钥,那我们是否可以用这个modulus,使用别的语言(比如PHP)来做密码加密呢?

想到就做,我在Google上搜索一下“PHP RSA”,找到了这个网站http://www.edsko.net/misc/,里面有PHP RSA的实现,不过我对它的rsa_encrypt($message, $public_key, $modulus, $keylength)方法产生了疑惑,它有4个参数,第一个是要加密的字串,那后面三个怎么填,我们现在仅知道的就是modulus了,而$public_key和$keylength从何而来呢,真有点摸不着头脑了,还是看看它带的例子吧,原来它例子里是从密钥对文件中取得相关的信息,QQ的密钥对文件自然取不到,那我只能自己生成一个密钥对文件,来看看有什么规律吧,在Linux下用openssl做

openssl genrsa -out key.pem 1024

生成了一个1024位的密钥对文件,可以打开看看,里面应该是Base64编码的,之后我们通过下面的命令可以得到modulus

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openssl rsa -in key.pem -noout -modulus
Modulus=D192471B8699640F931FE6F4FACC3E990B894F894CEA5BEE0DCBD7A4B76752F7345CF9B5F1271001B724F7A0ABF0A6E911E309536F4BE4749E92DCC531B8E36B95969D206649C9DD2371B413A8DFD9B92569660B1499A5CD310B86A8FDE24988E456897A416D2E7B0B649F0714F322C57EF92563B21A448D1072FF3806C34C75

比照QQ的,位数是一样的,接下来我们用命令

openssl rsa -in key.pem -text -noout

输出的内容如下:
Private-Key: (1024 bit)
modulus:
00:d1:92:47:1b:86:99:64:0f:93:1f:e6:f4:fa:cc:
3e:99:0b:89:4f:89:4c:ea:5b:ee:0d:cb:d7:a4:b7:
67:52:f7:34:5c:f9:b5:f1:27:10:01:b7:24:f7:a0:
ab:f0:a6:e9:11:e3:09:53:6f:4b:e4:74:9e:92:dc:
c5:31:b8:e3:6b:95:96:9d:20:66:49:c9:dd:23:71:
b4:13:a8:df:d9:b9:25:69:66:0b:14:99:a5:cd:31:
0b:86:a8:fd:e2:49:88:e4:56:89:7a:41:6d:2e:7b:
0b:64:9f:07:14:f3:22:c5:7e:f9:25:63:b2:1a:44:
8d:10:72:ff:38:06:c3:4c:75
publicExponent: 65537 (0x10001)
privateExponent:
00:83:d3:d9:08:f6:95:3c:bd:13:56:29:09:07:4e:
3d:3e:36:64:8c:74:98:be:7f:4f:72:bc:3c:0c:f0:
15:7d:b9:e4:e5:6b:6a:c8:a4:42:cc:61:71:4e:97:
72:30:f2:3d:80:33:e9:a4:e3:48:c1:0f:9e:c4:51:
3d:75:f6:90:8e:f3:c3:f8:ce:45:59:2a:67:42:a8:
c6:d0:4c:1d:12:c4:cf:53:f8:b1:58:b4:e1:23:71:
0e:e9:e9:e0:40:3d:9a:99:e3:5f:e1:93:04:e2:0a:
60:34:77:56:be:f9:8f:e6:4e:87:23:46:48:ba:38:
9d:dd:46:ce:20:b7:82:27:cd
prime1:
00:ee:a9:e4:70:9c:d4:fe:bf:cd:87:5c:00:cb:ea:
ef:82:92:e1:88:f7:99:6a:42:09:f4:fd:78:93:bd:
30:28:1f:2e:ed:c1:cd:d3:60:8b:34:52:89:a7:ac:
98:37:cd:96:81:1e:57:2f:46:08:0e:8d:fb:13:92:
8d:f5:7a:50:5f
prime2:
00:e0:cb:65:5e:31:f2:3b:c0:7f:93:ae:d9:6c:35:
75:e5:ce:8b:37:7d:39:ce:82:dd:9b:43:00:09:a6:
d8:c1:ab:bc:10:fe:3d:56:34:fe:bd:38:fe:fc:6c:
f2:74:a8:d6:40:25:e5:5a:35:7b:d0:24:71:44:8d:
53:23:71:83:ab
exponent1:
4b:d5:7f:d8:a8:7c:a5:55:9c:a0:de:03:02:c8:6b:
c2:39:99:a0:43:cc:63:8f:08:4a:e8:1f:60:12:45:
32:fa:75:96:e6:75:d8:2c:5d:0f:0b:0a:e2:54:5d:
29:9e:11:ac:85:4f:7e:9d:ea:01:75:eb:c9:94:4f:
b7:28:5e:51
exponent2:
00:9b:9f:d4:56:a8:e7:55:3c:88:55:fa:97:a5:55:
41:80:ce:44:0d:2f:51:a4:c9:6e:97:fd:83:7a:2b:
1b:26:c1:38:da:de:d8:21:e5:60:72:29:92:45:b9:
3b:05:4e:99:bd:21:3f:2d:fb:96:f2:db:37:db:48:
a7:c5:02:e2:2f
coefficient:
00:c2:75:38:a5:02:24:39:1e:0e:e9:ec:56:6a:31:
5d:38:82:ca:3e:9b:67:cb:40:7e:7b:2f:91:26:bb:
4e:64:3d:60:53:f1:21:67:8b:b7:af:f8:2e:95:f7:
af:cf:42:75:ab:6c:5c:42:97:42:17:94:17:ff:e0:
b9:cb:c9:e8:6d

通过它例子的代码,我明白了,$public_key应该是1024,$keylength就是65537,$modulus不能直接用这段文字,要先转成BigInteger,再转成文本传进去,BigInteger实现在PEAR里有,http://pear.php.net/package/Math_BigInteger

我们接下来就写程序吧

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include('rsa.php');
include('BigInteger.php');
 
$public = 65537;
$modulus = "D192471B8699640F931FE6F4FACC3E990B894F894CEA5BEE0DCBD7A4B76752F7345CF9B5F1271001B724F7A0ABF0A6E911E309536F4BE4749E92DCC531B8E36B95969D206649C9DD2371B413A8DFD9B92569660B1499A5CD310B86A8FDE24988E456897A416D2E7B0B649F0714F322C57EF92563B21A448D1072FF3806C34C75";
$keylength = 1024;
$modulus_16 = new Math_BigInteger($modulus,16);
$mend = $modulus_16->toString();
 
$encrypted = rsa_encrypt("test", $public, $mend, $keylength);
echo bin2hex($encrypted); //这里也可以用Base64,QQ就是Base64

最后说一下我对于RSA的理解,首先生成了公钥/私钥的密钥对,之后把公钥发布出去,外部系统用公钥加密,传给内部系统用私钥解密。