Android使用RSA加密和解密的示例代码

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专栏首页恩蓝脚本 Android使用RSA加密和解密的示例代码

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  /**RSA算法*/
  public static final String RSA = "RSA";
  /**加密方式，android的*/
// public static final String TRANSFORMATION = "RSA/None/NoPadding";
  /**加密方式，标准jdk的*/
  public static final String TRANSFORMATION = "RSA/None/PKCS1Padding";
  /** 使用公钥加密 */
  public static byte[] encryptByPublicKey(byte[] data, byte[] publicKey) throws Exception {
    // 得到公钥对象
    X509EncodedKeySpec keySpec = new X509EncodedKeySpec(publicKey);
    KeyFactory keyFactory = KeyFactory.getInstance("RSA");
    PublicKey pubKey = keyFactory.generatePublic(keySpec);
    // 加密数据
    Cipher cp = Cipher.getInstance(TRANSFORMATION);
    cp.init(Cipher.ENCRYPT_MODE, pubKey);
    return cp.doFinal(data);
  /** 使用私钥解密 */
  public static byte[] decryptByPrivateKey(byte[] encrypted, byte[] privateKey) throws Exception {
    // 得到私钥对象
    PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(privateKey);
    KeyFactory kf = KeyFactory.getInstance(RSA);
    PrivateKey keyPrivate = kf.generatePrivate(keySpec);
    // 解密数据
    Cipher cp = Cipher.getInstance(TRANSFORMATION);
    cp.init(Cipher.DECRYPT_MODE, keyPrivate);
    byte[] arr = cp.doFinal(encrypted);
    return arr;
  }

  String data = "hello world";
  try {
    int keyLength = 1024;
    //生成密钥对
    KeyPair keyPair = RSAUtils.generateRSAKeyPair(keyLength);
    //获取公钥
    byte[] publicKey = RSAUtils.getPublicKey(keyPair);
    //获取私钥
    byte[] privateKey = RSAUtils.getPrivateKey(keyPair);
    //用公钥加密
    byte[] encrypt = RSAUtils.encryptByPublicKey(data.getBytes(), publicKey);
    Log.d("TAG", "加密后的数据：" + StringUtils.byteArrayToString(encrypt));
    //用私钥解密
    byte[] decrypt = RSAUtils.decryptByPrivateKey(encrypt, privateKey);
    Log.d("TAG", "解密后的数据：" + new String(decrypt, "utf-8"));
  } catch (Exception e) {
    e.printStackTrace();
  }

    String data = "hello world";
    //读取公钥文件
    String publicKeyString = IOUtils.readAssetsFile(this, "rsa_public_key.pem");
    //base64解码
    byte[] publicKey = Base64Utils.decodeToBytes(publicKeyString);
    try {
      byte[] encrypt = RSAUtils.encryptByPublicKey(data.getBytes(), publicKey);
      Log.d("TAG", "加密后的数据：" + StringUtils.byteArrayToString(encrypt));
//     //读取私钥文件
//     String privateKeyString = IOUtils.readAssetsFile(this, "rsa_private_key.pem");
//     //base64解码
//     byte[] privateKey = Base64Utils.decodeToBytes(privateKeyString);
//     //解密
//     byte[] decrypt = RSAUtils.decryptByPrivateKey(encrypt, privateKey);
//     Log.d("TAG", "解密后的数据：" + new String(decrypt, "utf-8"));
    } catch (Exception e) {
      e.printStackTrace();
    }

/**秘钥默认长度*/
public static final int DEFAULT_KEY_SIZE = 1024;
/**加密的数据最大的字节数，即117个字节*/
public static final int DEFAULT_BUFFERSIZE = (DEFAULT_KEY_SIZE / 8) - 11;
/**当加密的数据超过DEFAULT_BUFFERSIZE，则使用分段加密*/
public static final byte[] DEFAULT_SPLIT = "#PART#".getBytes();
/** 使用公钥分段加密 */
public static byte[] encryptByPublicKeyForSpilt(byte[] data, byte[] publicKey) throws Exception{
int dataLen = data.length;
if (dataLen <= DEFAULT_BUFFERSIZE) {
return encryptByPublicKey(data, publicKey);
List<Byte  allBytes = new ArrayList<Byte (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;
/** 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<Byte  allBytes = new ArrayList<Byte (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;
}

String data = "hello world hello world hello world hello world hello world hello world hello world hello world " +
"hello world hello world hello world hello world hello world hello world hello world hello world hello world " +
"hello world hello world hello world hello world hello world hello world hello world hello world hello world ";
Log.d("TAG", "要加密的数据：" + data + ", 要加密的数据长度：" + data.length());
try {
//分段加密
byte[] encrypt = RSAUtils.encryptByPublicKeyForSpilt(data.getBytes(), publicKey);
Log.d("TAG", "加密后的数据：" + StringUtils.byteArrayToString(encrypt));
//分段解密
byte[] decrypt = RSAUtils.decryptByPrivateKeyForSpilt(encrypt, privateKey);
Log.d("TAG", "解密后的数据：" + new String(decrypt, "utf-8"));
} catch (Exception e) {
e.printStackTrace();
}

/** 生成密钥对，即公钥和私钥。key长度是512-2048，一般为1024 */
public static KeyPair generateRSAKeyPair(int keyLength) throws NoSuchAlgorithmException {
KeyPairGenerator kpg = KeyPairGenerator.getInstance(RSA);
kpg.initialize(keyLength);
return kpg.genKeyPair();
/** 获取公钥，打印为48-12613448136942-12272-122-913111503-126115048-12...等等一长串用-拼接的数字 */
public static byte[] getPublicKey(KeyPair keyPair) {
RSAPublicKey rsaPublicKey = (RSAPublicKey) keyPair.getPublic();
return rsaPublicKey.getEncoded();
/** 获取私钥，同上 */
public static byte[] getPrivateKey(KeyPair keyPair) {
RSAPrivateKey rsaPrivateKey = (RSAPrivateKey) keyPair.getPrivate();
return rsaPrivateKey.getEncoded();
}

int keyLength = 1024;
try {
//生成密钥对
KeyPair keyPair = RSAUtils.generateRSAKeyPair(keyLength);
//获取公钥
byte[] publicKey = RSAUtils.getPublicKey(keyPair);
Log.d("TAG", "公钥：" + StringUtils.byteArrayToString(publicKey));
//公钥用base64编码
String encodePublic = Base64Utils.encodeToString(publicKey);
Log.d("TAG", "base64编码的公钥：" + encodePublic);
//获取私钥
byte[] privateKey = RSAUtils.getPrivateKey(keyPair);
Log.d("TAG", "私钥：" + StringUtils.byteArrayToString(privateKey));
//私钥用base64编码
String encodePrivate = Base64Utils.encodeToString(privateKey);
Log.d("TAG", "base64编码的私钥：" + encodePrivate);

砸漏

Android使用RSA加密和解密的示例代码

Android使用RSA加密和解密的示例代码