Android关于RSA加密和解密

新APP用了RSA加密进行传输 

本来调试的时候,本地加密解密很愉快 

加密方法

    public static byte[] encryptData(byte[] data, PublicKey publicKey) {        try {            Cipher cipher = Cipher.getInstance("RSA");            cipher.init(Cipher.ENCRYPT_MODE, publicKey);            return cipher.doFinal(data);        } catch (Exception e) {            e.printStackTrace();            return null;        }    }

解密方法

    public static byte[] decryptData(byte[] encryptedData, PrivateKey privateKey) {        try {            Cipher cipher = Cipher.getInstance("RSA");            cipher.init(Cipher.DECRYPT_MODE, privateKey);            return cipher.doFinal(encryptedData);        } catch (Exception e) {            return null;        }    }

转着花样玩,把自己私钥转成字符串然后再通过生成的私钥字符串转成私钥把刚才通过公钥加密后的内容进行解密以模仿数据真实传输.

自己用公钥加密后的密文是这样的

DFxJrPu6z1hrlLZQoO7NWXehX350QPt9phkELuGi37780RHzEZYYNP6ZeA98Vo5d/e6RCVkopSJM+X1V/+Jsm8Pzcbm

EkzefCXISkshD4D3to7NAOuxwk7emKi8QZDAEYazI9nTbivKI/92UqYdMKGOxYa6V6kY7jcKxV8qhMDg=

然后自己用私钥进行解密也是很愉快的 完全没有问题

后来和服务端联调的时候出现点小问题

台给我们传过来的密文是16进制的字符串

95578b364f62d4c7ea24c9891fa41e407debfcab2098e08fb34faa8a55576e99f0d1bab31026f6e42db883de648ddd

43a5a7de51bb0b7b568d9b46a975ffce127a3997035a10e0203ea87c5d3a8281a7de3f2eee568247e093548fc092

a62b9c26db990c24f8cf4f2c11c589212799079cf93d9ae83bbf51ee97a925bfedee43

我的内心毫无波动,据说是后台生成的密文是一堆乱码,我也没功夫研究后台日至输出,猜测是编码问题,反正不能直接给可以直接解密的字符串了,然后就进行了小型转换,输出的密文先是进行了Base64的decode,得到的二进制数组再转变成16进制字符串,然后把字符串给我们传过来了

然后我们就需要转回去,把16进制的字符串转成2进制数组,再进行Base64的encode,得到的就是可以直接用私钥进行解密的字符串了. 同样,我们向服务器传输的时候需要用同样的方法,得到的密文先进行decode变成2进制数组,然后再转成16进制字符串,把字符串传递给后台

就是这样,本来挺简单的,还要多写很多方法 不去深究了,要是后台能直接用加密字符串就可直接略过这一段,能用就可以

解密调试中还出现了乱码问题  后台和Android端都出现过  

解密后的内容还附带了一堆乱码,像病毒一样,真实数据混在乱码里面 如图

"这是明文" 是正确的解密内容,但是多了很多乱码  iOS貌似没出问题  

后台和Android都是这样,后来一起研究发现是解密出现问题   因为iOS解密没问题    需要在解密方法中做一些修整

      Cipher cipher = Cipher.getInstance("RSA");

这行代码修改成

      Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");

这样就行了    我看一眼以为是路径问题,架构师说这可能是算法问题       至于加密的这个地方不做修改

基本就这样.没有写Demo,其实就两个工具类

public class RSAUtils {    //    private static String RSA = "RSA/ECB/PKCS1Padding";    private static String RSA = "RSA";    /**     * 随机生成RSA密钥对(默认密钥长度为1024)     *     * @return     */    public static KeyPair generateRSAKeyPair() {        return generateRSAKeyPair(1024);    }    /**     * 随机生成RSA密钥对     *     * @param keyLength 密钥长度，范围：512～2048<br>     *                  一般1024     * @return     */    public static KeyPair generateRSAKeyPair(int keyLength) {        try {            KeyPairGenerator kpg = KeyPairGenerator.getInstance(RSA);            kpg.initialize(keyLength);            return kpg.genKeyPair();        } catch (NoSuchAlgorithmException e) {            e.printStackTrace();            return null;        }    }    /**     * 用公钥加密 <br>     * 每次加密的字节数，不能超过密钥的长度值减去11     *     * @param data      需加密数据的byte数据     * @param publicKey 公钥     * @return 加密后的byte型数据     */    public static byte[] encryptData(byte[] data, PublicKey publicKey) {        try {            Cipher cipher = Cipher.getInstance(RSA);            // 编码前设定编码方式及密钥            cipher.init(Cipher.ENCRYPT_MODE, publicKey);            // 传入编码数据并返回编码结果            return cipher.doFinal(data);        } catch (Exception e) {            e.printStackTrace();            return null;        }    }    /**     * 用私钥解密     *     * @param encryptedData 经过encryptedData()加密返回的byte数据     * @param privateKey    私钥     * @return     */    public static byte[] decryptData(byte[] encryptedData, PrivateKey privateKey) {        try {            Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");            cipher.init(Cipher.DECRYPT_MODE, privateKey);            return cipher.doFinal(encryptedData);        } catch (Exception e) {            return null;        }    }    /**     * 通过公钥byte[](publicKey.getEncoded())将公钥还原，适用于RSA算法     *     * @param keyBytes     * @return     * @throws NoSuchAlgorithmException     * @throws InvalidKeySpecException     */    public static PublicKey getPublicKey(byte[] keyBytes) throws NoSuchAlgorithmException,            InvalidKeySpecException {        X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes);        KeyFactory keyFactory = KeyFactory.getInstance(RSA);        PublicKey publicKey = keyFactory.generatePublic(keySpec);        return publicKey;    }    /**     * 通过私钥byte[]将公钥还原，适用于RSA算法     *     * @param keyBytes     * @return     * @throws NoSuchAlgorithmException     * @throws InvalidKeySpecException     */    public static PrivateKey getPrivateKey(byte[] keyBytes) throws NoSuchAlgorithmException,            InvalidKeySpecException {        PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(keyBytes);        KeyFactory keyFactory = KeyFactory.getInstance(RSA);        PrivateKey privateKey = keyFactory.generatePrivate(keySpec);        return privateKey;    }    /**     * 使用N、e值还原公钥     *     * @param modulus     * @param publicExponent     * @return     * @throws NoSuchAlgorithmException     * @throws InvalidKeySpecException     */    public static PublicKey getPublicKey(String modulus, String publicExponent)            throws NoSuchAlgorithmException, InvalidKeySpecException {        BigInteger bigIntModulus = new BigInteger(modulus);        BigInteger bigIntPrivateExponent = new BigInteger(publicExponent);        RSAPublicKeySpec keySpec = new RSAPublicKeySpec(bigIntModulus, bigIntPrivateExponent);        KeyFactory keyFactory = KeyFactory.getInstance(RSA);        PublicKey publicKey = keyFactory.generatePublic(keySpec);        return publicKey;    }    /**     * 使用N、d值还原私钥     *     * @param modulus     * @param privateExponent     * @return     * @throws NoSuchAlgorithmException     * @throws InvalidKeySpecException     */    public static PrivateKey getPrivateKey(String modulus, String privateExponent)            throws NoSuchAlgorithmException, InvalidKeySpecException {        BigInteger bigIntModulus = new BigInteger(modulus);        BigInteger bigIntPrivateExponent = new BigInteger(privateExponent);        RSAPublicKeySpec keySpec = new RSAPublicKeySpec(bigIntModulus, bigIntPrivateExponent);        KeyFactory keyFactory = KeyFactory.getInstance(RSA);        PrivateKey privateKey = keyFactory.generatePrivate(keySpec);        return privateKey;    }    /**     * 从字符串中加载公钥     *     * @param publicKeyStr 公钥数据字符串     * @throws Exception 加载公钥时产生的异常     */    public static PublicKey loadPublicKey(String publicKeyStr) throws Exception {        try {            byte[] buffer = Base64Utils.decode(publicKeyStr);            KeyFactory keyFactory = KeyFactory.getInstance(RSA);            X509EncodedKeySpec keySpec = new X509EncodedKeySpec(buffer);            return (RSAPublicKey) keyFactory.generatePublic(keySpec);        } catch (NoSuchAlgorithmException e) {            throw new Exception("无此算法");        } catch (InvalidKeySpecException e) {            throw new Exception("公钥非法");        } catch (NullPointerException e) {            throw new Exception("公钥数据为空");        }    }    /**     * 从字符串中加载私钥<br>     * 加载时使用的是PKCS8EncodedKeySpec（PKCS#8编码的Key指令）。     *     * @param privateKeyStr     * @return     * @throws Exception     */    public static PrivateKey loadPrivateKey(String privateKeyStr) throws Exception {        try {            byte[] buffer = Base64Utils.decode(privateKeyStr);            // X509EncodedKeySpec keySpec = new X509EncodedKeySpec(buffer);            PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(buffer);            KeyFactory keyFactory = KeyFactory.getInstance(RSA);            return (RSAPrivateKey) keyFactory.generatePrivate(keySpec);        } catch (NoSuchAlgorithmException e) {            throw new Exception("无此算法");        } catch (InvalidKeySpecException e) {            throw new Exception("私钥非法");        } catch (NullPointerException e) {            throw new Exception("私钥数据为空");        }    }    /**     * 从文件中输入流中加载公钥     *     * @param in 公钥输入流     * @throws Exception 加载公钥时产生的异常     */    public static PublicKey loadPublicKey(InputStream in) throws Exception {        try {            return loadPublicKey(readKey(in));        } catch (IOException e) {            throw new Exception("公钥数据流读取错误");        } catch (NullPointerException e) {            throw new Exception("公钥输入流为空");        }    }    /**     * 从文件中加载私钥     *     * @param in 私钥文件名     * @return 是否成功     * @throws Exception     */    public static PrivateKey loadPrivateKey(InputStream in) throws Exception {        try {            return loadPrivateKey(readKey(in));        } catch (IOException e) {            throw new Exception("私钥数据读取错误");        } catch (NullPointerException e) {            throw new Exception("私钥输入流为空");        }    }    /**     * 读取密钥信息     *     * @param in     * @return     * @throws IOException     */    private static String readKey(InputStream in) throws IOException {        BufferedReader br = new BufferedReader(new InputStreamReader(in));        String readLine = null;        StringBuilder sb = new StringBuilder();        while ((readLine = br.readLine()) != null) {            if (readLine.charAt(0) == '-') {                continue;            } else {                sb.append(readLine);                sb.append('\r');            }        }        return sb.toString();    }    /**     * 打印公钥信息     *     * @param publicKey     */    public static void printPublicKeyInfo(PublicKey publicKey) {        RSAPublicKey rsaPublicKey = (RSAPublicKey) publicKey;        System.out.println("----------RSAPublicKey----------");        System.out.println("Modulus.length=" + rsaPublicKey.getModulus().bitLength());        System.out.println("Modulus=" + rsaPublicKey.getModulus().toString());        System.out.println("PublicExponent.length=" + rsaPublicKey.getPublicExponent().bitLength());        System.out.println("PublicExponent=" + rsaPublicKey.getPublicExponent().toString());    }    public static void printPrivateKeyInfo(PrivateKey privateKey) {        RSAPrivateKey rsaPrivateKey = (RSAPrivateKey) privateKey;        System.out.println("----------RSAPrivateKey ----------");        System.out.println("Modulus.length=" + rsaPrivateKey.getModulus().bitLength());        System.out.println("Modulus=" + rsaPrivateKey.getModulus().toString());        System.out.println("PrivateExponent.length=" + rsaPrivateKey.getPrivateExponent().bitLength());        System.out.println("PrivatecExponent=" + rsaPrivateKey.getPrivateExponent().toString());    }    /**     * 得到密钥字符串（经过base64编码）     *     * @return     */    public static String getKeyString(Key key) throws Exception {        byte[] keyBytes = key.getEncoded();        String s = Base64Utils.encode(keyBytes);        return s;    }    /**     * 16进制字符串转字节数组     * @param src     *            16进制字符串     * @return 字节数组     * @throws     */    public static byte[] hexString2Bytes(String src) {        int l = src.length() / 2;        byte[] ret = new byte[l];        for (int i = 0; i < l; i++) {            ret[i] = (byte) Integer                    .valueOf(src.substring(i * 2, i * 2 + 2), 16).byteValue();        }        return ret;    }    /**     * 16进制字符串转字符串     * @param src     *            16进制字符串     * @return 字节数组     * @throws     */    public static String hexString2String(String src) {        String temp = "";        for (int i = 0; i < src.length() / 2; i++) {            temp = temp                    + (char) Integer.valueOf(src.substring(i * 2, i * 2 + 2),                    16).byteValue();        }        return temp;    }    /**     * 字符串转16进制字符串     * @param strPart     *            字符串     * @return 16进制字符串     * @throws     */    public static String string2HexString(String strPart) {        StringBuffer hexString = new StringBuffer();        for (int i = 0; i < strPart.length(); i++) {            int ch = (int) strPart.charAt(i);            String strHex = Integer.toHexString(ch);            hexString.append(strHex);        }        return hexString.toString();    }    /**     * 字节数组转16进制字符串     * @param b     *            字节数组     * @return 16进制字符串     * @throws     */    public static String bytes2HexString(byte[] b) {        StringBuffer result = new StringBuffer();        String hex;        for (int i = 0; i < b.length; i++) {            hex = Integer.toHexString(b[i] & 0xFF);            if (hex.length() == 1) {                hex = '0' + hex;            }            result.append(hex.toUpperCase());        }        return result.toString();    }}

还有个Base64的

public class Base64Utils {    private static char[] base64EncodeChars = new char[]            {'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T',                    'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm',                    'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', '0', '1', '2', '3', '4', '5',                    '6', '7', '8', '9', '+', '/'};    private static byte[] base64DecodeChars = new byte[]            {-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,                    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63, 52, 53,                    54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11,                    12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1, -1, 26, 27, 28, 29,                    30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1,                    -1, -1, -1};    /**     * 加密     *     * @param data     * @return     */    public static String encode(byte[] data) {        StringBuffer sb = new StringBuffer();        int len = data.length;        int i = 0;        int b1, b2, b3;        while (i < len) {            b1 = data[i++] & 0xff;            if (i == len) {                sb.append(base64EncodeChars[b1 >>> 2]);                sb.append(base64EncodeChars[(b1 & 0x3) << 4]);                sb.append("==");                break;            }            b2 = data[i++] & 0xff;            if (i == len) {                sb.append(base64EncodeChars[b1 >>> 2]);                sb.append(base64EncodeChars[((b1 & 0x03) << 4) | ((b2 & 0xf0) >>> 4)]);                sb.append(base64EncodeChars[(b2 & 0x0f) << 2]);                sb.append("=");                break;            }            b3 = data[i++] & 0xff;            sb.append(base64EncodeChars[b1 >>> 2]);            sb.append(base64EncodeChars[((b1 & 0x03) << 4) | ((b2 & 0xf0) >>> 4)]);            sb.append(base64EncodeChars[((b2 & 0x0f) << 2) | ((b3 & 0xc0) >>> 6)]);            sb.append(base64EncodeChars[b3 & 0x3f]);        }        return sb.toString();    }    /**     * 解密     *     * @param str     * @return     */    public static byte[] decode(String str) {        try {            return decodePrivate(str);        } catch (UnsupportedEncodingException e) {            e.printStackTrace();        }        return new byte[]                {};    }    private static byte[] decodePrivate(String str) throws UnsupportedEncodingException {        StringBuffer sb = new StringBuffer();        byte[] data = null;        data = str.getBytes("US-ASCII");        int len = data.length;        int i = 0;        int b1, b2, b3, b4;        while (i < len) {            do {                b1 = base64DecodeChars[data[i++]];            } while (i < len && b1 == -1);            if (b1 == -1)                break;            do {                b2 = base64DecodeChars[data[i++]];            } while (i < len && b2 == -1);            if (b2 == -1)                break;            sb.append((char) ((b1 << 2) | ((b2 & 0x30) >>> 4)));            do {                b3 = data[i++];                if (b3 == 61)                    return sb.toString().getBytes("iso8859-1");                b3 = base64DecodeChars[b3];            } while (i < len && b3 == -1);            if (b3 == -1)                break;            sb.append((char) (((b2 & 0x0f) << 4) | ((b3 & 0x3c) >>> 2)));            do {                b4 = data[i++];                if (b4 == 61)                    return sb.toString().getBytes("iso8859-1");                b4 = base64DecodeChars[b4];            } while (i < len && b4 == -1);            if (b4 == -1)                break;            sb.append((char) (((b3 & 0x03) << 6) | b4));        }        return sb.toString().getBytes("iso8859-1");    }}

最后应用  

加密 

                String source = "3月2日";                byte[] encryptByte = RSAUtils.encryptData(source.getBytes(), publicKey111);                String afterencrypt = Base64Utils.encode(encryptByte);

最后的字符串就是 加密后的密文 

解密

                String encryptContent = Body.getCode();                byte[] decryptByte = RSAUtils.decryptData(Base64Utils.decode(encryptContent), privateKey);                String decryptStr = new String(decryptByte);

Body.getCode()方法是获取到加密后的字符串     

最后的decryptStr是解密后的字符串    

大概就是这样了   RSA只适合用作登录时候加密  正常的数据传输用AES就差不多了