Android(安卓)RSA 加密(分段加密)

package com.dhh.easy.wahu.utils;import android.util.*;import android.util.Base64;import java.security.KeyFactory;import java.security.KeyPair;import java.security.KeyPairGenerator;import java.security.NoSuchAlgorithmException;import java.security.PrivateKey;import java.security.PublicKey;import java.security.spec.PKCS8EncodedKeySpec;import java.security.spec.X509EncodedKeySpec;import java.util.ArrayList;import java.util.List;import javax.crypto.Cipher;/** * Created by Administrator on 2019/5/17 0017. */public class RSAAndroid {    private static String TAG = "RSAAndroid";    public static final String RSA = "RSA";// 非对称加密密钥算法    public static final String ECB_PKCS1_PADDING = "RSA/ECB/PKCS1Padding";//加密填充方式    public static final int DEFAULT_KEY_SIZE = 2048;//秘钥默认长度    public static final byte[] DEFAULT_SPLIT = "#PART#".getBytes();    // 当要加密的内容超过bufferSize，则采用partSplit进行分块加密    public static final int DEFAULT_BUFFERSIZE = (DEFAULT_KEY_SIZE / 8) - 11;// 当前秘钥支持加密的最大字节数    /**     * 随机生成RSA密钥对     *     * @param keyLength 密钥长度，范围：512～2048     *                  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;        }    }    /**     * 用公钥对字符串进行加密     *     * @param data 原文     */    public static byte[] encryptByPublicKey(byte[] data, byte[] publicKey) throws Exception {        // 得到公钥        X509EncodedKeySpec keySpec = new X509EncodedKeySpec(publicKey);        KeyFactory kf = KeyFactory.getInstance(RSA);        PublicKey keyPublic = kf.generatePublic(keySpec);        // 加密数据        Cipher cp = Cipher.getInstance(ECB_PKCS1_PADDING);        cp.init(Cipher.ENCRYPT_MODE, keyPublic);        return cp.doFinal(data);    }    /**     * 私钥加密     *     * @param data       待加密数据     * @param privateKey 密钥     * @return byte[] 加密数据     */    public static byte[] encryptByPrivateKey(byte[] data, byte[] privateKey) throws Exception {        // 得到私钥        PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(privateKey);        KeyFactory kf = KeyFactory.getInstance(RSA);        PrivateKey keyPrivate = kf.generatePrivate(keySpec);        // 数据加密        Cipher cipher = Cipher.getInstance(ECB_PKCS1_PADDING);        cipher.init(Cipher.ENCRYPT_MODE, keyPrivate);        return cipher.doFinal(data);    }    /**     * 公钥解密     *     * @param data      待解密数据     * @param publicKey 密钥     * @return byte[] 解密数据     */    public static byte[] decryptByPublicKey(byte[] data, byte[] publicKey) throws Exception {        // 得到公钥        X509EncodedKeySpec keySpec = new X509EncodedKeySpec(publicKey);        KeyFactory kf = KeyFactory.getInstance(RSA);        PublicKey keyPublic = kf.generatePublic(keySpec);        // 数据解密        Cipher cipher = Cipher.getInstance(ECB_PKCS1_PADDING);        cipher.init(Cipher.DECRYPT_MODE, keyPublic);        return cipher.doFinal(data);    }    /**     * 使用私钥进行解密     */    public static byte[] decryptByPrivateKey(byte[] encrypted, byte[] privateKey) throws Exception {        // 得到私钥        PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(privateKey);        KeyFactory kf = KeyFactory.getInstance(RSA);        PrivateKey keyPrivate = kf.generatePrivate(keySpec);        // 解密数据        Cipher cp = Cipher.getInstance(ECB_PKCS1_PADDING);        cp.init(Cipher.DECRYPT_MODE, keyPrivate);        byte[] arr = cp.doFinal(encrypted);        return arr;    }    /**     * 用公钥对字符串进行分段加密     *     */    public static byte[] encryptByPublicKeyForSpilt(byte[] data, byte[] publicKey) throws Exception {        int dataLen = data.length;        if (dataLen <= DEFAULT_BUFFERSIZE) {            return encryptByPublicKey(data, publicKey);        }        List allBytes = new ArrayList(2048);        int bufIndex = 0;        int subDataLoop = 0;        byte[] buf = new byte[DEFAULT_BUFFERSIZE];        for (int i = 0; i < dataLen; i++) {            buf[bufIndex] = data[i];            if (++bufIndex == DEFAULT_BUFFERSIZE || i == dataLen - 1) {                subDataLoop++;                if (subDataLoop != 1) {                    for (byte b : DEFAULT_SPLIT) {                        allBytes.add(b);                    }                }                byte[] encryptBytes = encryptByPublicKey(buf, publicKey);                for (byte b : encryptBytes) {                    allBytes.add(b);                }                bufIndex = 0;                if (i == dataLen - 1) {                    buf = null;                } else {                    buf = new byte[Math.min(DEFAULT_BUFFERSIZE, dataLen - i - 1)];                }            }        }        byte[] bytes = new byte[allBytes.size()];        {            int i = 0;            for (Byte b : allBytes) {                bytes[i++] = b.byteValue();            }        }        return bytes;    }    /**     * 分段加密     *     * @param data       要加密的原始数据     * @param privateKey 秘钥     */    public static byte[] encryptByPrivateKeyForSpilt(byte[] data, byte[] privateKey) throws Exception {        int dataLen = data.length;        if (dataLen <= DEFAULT_BUFFERSIZE) {            return encryptByPrivateKey(data, privateKey);        }        List allBytes = new ArrayList(2048);        int bufIndex = 0;        int subDataLoop = 0;        byte[] buf = new byte[DEFAULT_BUFFERSIZE];        for (int i = 0; i < dataLen; i++) {            buf[bufIndex] = data[i];            if (++bufIndex == DEFAULT_BUFFERSIZE || i == dataLen - 1) {                subDataLoop++;                if (subDataLoop != 1) {                    for (byte b : DEFAULT_SPLIT) {                        allBytes.add(b);                    }                }                byte[] encryptBytes = encryptByPrivateKey(buf, privateKey);                for (byte b : encryptBytes) {                    allBytes.add(b);                }                bufIndex = 0;                if (i == dataLen - 1) {                    buf = null;                } else {                    buf = new byte[Math.min(DEFAULT_BUFFERSIZE, dataLen - i - 1)];                }            }        }        byte[] bytes = new byte[allBytes.size()];        {            int i = 0;            for (Byte b : allBytes) {                bytes[i++] = b.byteValue();            }        }        return bytes;    }    /**     * 公钥分段解密     *     * @param encrypted 待解密数据     * @param publicKey 密钥     */    public static byte[] decryptByPublicKeyForSpilt(byte[] encrypted, byte[] publicKey) throws Exception {        int splitLen = DEFAULT_SPLIT.length;        if (splitLen <= 0) {            return decryptByPublicKey(encrypted, publicKey);        }        int dataLen = encrypted.length;        List allBytes = new ArrayList(1024);        int latestStartIndex = 0;        for (int i = 0; i < dataLen; i++) {            byte bt = encrypted[i];            boolean isMatchSplit = false;            if (i == dataLen - 1) {                // 到data的最后了                byte[] part = new byte[dataLen - latestStartIndex];                System.arraycopy(encrypted, latestStartIndex, part, 0, part.length);                byte[] decryptPart = decryptByPublicKey(part, publicKey);                for (byte b : decryptPart) {                    allBytes.add(b);                }                latestStartIndex = i + splitLen;                i = latestStartIndex - 1;            } else if (bt == DEFAULT_SPLIT[0]) {                // 这个是以split[0]开头                if (splitLen > 1) {                    if (i + splitLen < dataLen) {                        // 没有超出data的范围                        for (int j = 1; j < splitLen; j++) {                            if (DEFAULT_SPLIT[j] != encrypted[i + j]) {                                break;                            }                            if (j == splitLen - 1) {                                // 验证到split的最后一位，都没有break，则表明已经确认是split段                                isMatchSplit = true;                            }                        }                    }                } else {                    // split只有一位，则已经匹配了                    isMatchSplit = true;                }            }            if (isMatchSplit) {                byte[] part = new byte[i - latestStartIndex];                System.arraycopy(encrypted, latestStartIndex, part, 0, part.length);                byte[] decryptPart = decryptByPublicKey(part, publicKey);                for (byte b : decryptPart) {                    allBytes.add(b);                }                latestStartIndex = i + splitLen;                i = latestStartIndex - 1;            }        }        byte[] bytes = new byte[allBytes.size()];        {            int i = 0;            for (Byte b : allBytes) {                bytes[i++] = b.byteValue();            }        }        return bytes;    }    /**     * 使用私钥分段解密     *     */    public static byte[] decryptByPrivateKeyForSpilt(byte[] encrypted, byte[] privateKey) throws Exception {        int splitLen = DEFAULT_SPLIT.length;        if (splitLen <= 0) {            return decryptByPrivateKey(encrypted, privateKey);        }        int dataLen = encrypted.length;        List allBytes = new ArrayList(1024);        int latestStartIndex = 0;        for (int i = 0; i < dataLen; i++) {            byte bt = encrypted[i];            boolean isMatchSplit = false;            if (i == dataLen - 1) {                // 到data的最后了                byte[] part = new byte[dataLen - latestStartIndex];                System.arraycopy(encrypted, latestStartIndex, part, 0, part.length);                byte[] decryptPart = decryptByPrivateKey(part, privateKey);                for (byte b : decryptPart) {                    allBytes.add(b);                }                latestStartIndex = i + splitLen;                i = latestStartIndex - 1;            } else if (bt == DEFAULT_SPLIT[0]) {                // 这个是以split[0]开头                if (splitLen > 1) {                    if (i + splitLen < dataLen) {                        // 没有超出data的范围                        for (int j = 1; j < splitLen; j++) {                            if (DEFAULT_SPLIT[j] != encrypted[i + j]) {                                break;                            }                            if (j == splitLen - 1) {                                // 验证到split的最后一位，都没有break，则表明已经确认是split段                                isMatchSplit = true;                            }                        }                    }                } else {                    // split只有一位，则已经匹配了                    isMatchSplit = true;                }            }            if (isMatchSplit) {                byte[] part = new byte[i - latestStartIndex];                System.arraycopy(encrypted, latestStartIndex, part, 0, part.length);                byte[] decryptPart = decryptByPrivateKey(part, privateKey);                for (byte b : decryptPart) {                    allBytes.add(b);                }                latestStartIndex = i + splitLen;                i = latestStartIndex - 1;            }        }        byte[] bytes = new byte[allBytes.size()];        {            int i = 0;            for (Byte b : allBytes) {                bytes[i++] = b.byteValue();            }        }        return bytes;    }    public static void testEncrypt(String content) {        //生成秘钥对        KeyPair keyPair = RSAAndroid.generateRSAKeyPair(RSAAndroid.DEFAULT_KEY_SIZE);        //公钥        PublicKey publicKey = keyPair.getPublic();        //私钥        PrivateKey privateKey = keyPair.getPrivate();        long start;        long end;        byte[] encryptBytes = new byte[0];        byte[] decryptBytes = new byte[0];        String encryStr, decryStr;        try {            //公钥加密            start = System.currentTimeMillis();            encryptBytes = RSAAndroid.encryptByPublicKeyForSpilt(content.getBytes(), publicKey.getEncoded());            Log.i(TAG, "testEncrypt: 公钥加密 encryptBytes:"+encryptBytes);            end = System.currentTimeMillis();            Log.e(TAG, "公钥加密耗时 cost time---->" + (end - start));            //encryStr = BASE64Encoder.encode(encryptBytes);            encryStr = android.util.Base64.encodeToString(encryptBytes, Base64.DEFAULT);//            Log.e(TAG, "加密后json数据 --1-->" + encryStr);            Log.e(TAG, "加密后json数据长度 --1-->" + encryStr.length());            Log.i(TAG, "testEncrypt: encryStr:"+encryStr);            //私钥解密            start = System.currentTimeMillis();            decryptBytes = RSAAndroid.decryptByPrivateKeyForSpilt(Base64.decode(encryStr,Base64.DEFAULT), privateKey.getEncoded());            decryStr = new String(decryptBytes);            Log.i(TAG, "testEncrypt: 私钥解密 decryStr:"+decryStr);            end = System.currentTimeMillis();            Log.e(TAG, "私钥解密耗时 cost time---->" + (end - start));            Log.e(TAG, "解密后json数据 --1-->" + decryStr);        } catch (Exception e) {            e.printStackTrace();        }        try {            //私钥加密            start = System.currentTimeMillis();            encryptBytes = RSAAndroid.encryptByPrivateKeyForSpilt(content.getBytes(), privateKey.getEncoded());            end = System.currentTimeMillis();            Log.e(TAG, "私钥加密密耗时 cost time---->" + (end - start));            encryStr = android.util.Base64.encodeToString(encryptBytes, Base64.DEFAULT);//            Log.e(TAG, "加密后json数据 --2-->" + encryStr);            Log.e(TAG, "加密后json数据长度 --2-->" + encryStr.length());            Log.i(TAG, "testEncrypt: 私钥加密密 encryStr:"+encryStr);            //公钥解密            start = System.currentTimeMillis();            decryptBytes = RSAAndroid.decryptByPublicKeyForSpilt(Base64.decode(encryStr,Base64.DEFAULT), publicKey.getEncoded());            decryStr = new String(decryptBytes);            Log.i(TAG, "testEncrypt: 公钥解密 decryStr:"+decryStr);            end = System.currentTimeMillis();            Log.e(TAG, "公钥解密耗时 cost time---->" + (end - start));            Log.e(TAG, "解密后json数据 --2-->" + decryStr);        } catch (Exception e) {            e.printStackTrace();        }    }}

Android 数据加密之Rsa加密 https://blog.csdn.net/qq_26057629/article/details/81776133
https://blog.csdn.net/fugang1230/article/details/79379490
RSA 解密的时候报错而且有乱码:java.lang.ArrayIndexOutOfBoundsException: too much data for RSA block https://blog.csdn.net/Rodulf/article/details/50957311
too much data for RSA block .关于RSA算法密钥长度/密文长度/明文长度 https://blog.csdn.net/centralperk/article/details/8553759
https://blog.csdn.net/qqxiaoqiang1573/article/details/51253808 Base64 加密解密字符串的简单使用
https://www.cnblogs.com/zhujiabin/p/7877777.html

//import android.util.Base64;  String str = "Hello!";  //base64编码  //String strBase64 = new String(Base64.encode(str.getBytes(), Base64.DEFAULT));  String strBase64 = Base64.encodeToString(str.getBytes(), Base64.DEFAULT);  //base64解码  String str2 = new String(Base64.decode(strBase64.getBytes(), Base64.DEFAULT));

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