Android 获取签名公钥和公钥私钥加解密的方法(推荐)

public class GetPublicKey {     /**   * 获取签名公钥   * @param mContext   * @return   */  protected static String getSignInfo(Context mContext) {    String signcode = "";    try {      PackageInfo packageInfo = mContext.getPackageManager().getPackageInfo(          GetAppInfo.getPackageName(mContext), PackageManager.GET_SIGNATURES);      Signature[] signs = packageInfo.signatures;      Signature sign = signs[0];       signcode = parseSignature(sign.toByteArray());      signcode = signcode.toLowerCase();    } catch (Exception e) {      Log.e(Constants.TAG, e.getMessage(), e);    }    return signcode;  }   protected static String parseSignature(byte[] signature) {    String sign = "";    try {      CertificateFactory certFactory = CertificateFactory          .getInstance("X.509");      X509Certificate cert = (X509Certificate) certFactory          .generateCertificate(new ByteArrayInputStream(signature));      String pubKey = cert.getPublicKey().toString();      String ss = subString(pubKey);      ss = ss.replace(",", "");      ss = ss.toLowerCase();      int aa = ss.indexOf("modulus");      int bb = ss.indexOf("publicexponent");      sign = ss.substring(aa + 8, bb);    } catch (CertificateException e) {      Log.e(Constants.TAG, e.getMessage(), e);    }    return sign;  }   public static String subString(String sub) {    Pattern pp = Pattern.compile("//s*|/t|/r|/n");    Matcher mm = pp.matcher(sub);    return mm.replaceAll("");  }}package com.example.xscamera; import java.io.ByteArrayOutputStream;import java.security.Key;import java.security.KeyFactory;import java.security.KeyPair;import java.security.KeyPairGenerator;import java.security.PrivateKey;import java.security.PublicKey;import java.security.Signature;import java.security.interfaces.RSAPrivateKey;import java.security.interfaces.RSAPublicKey;import java.security.spec.PKCS8EncodedKeySpec;import java.security.spec.X509EncodedKeySpec;import java.util.HashMap;import java.util.Map;import javax.crypto.Cipher; /** * <p> * RSA公钥/私钥/签名工具包 * <p> * 字符串格式的密钥在未在特殊说明情况下都为BASE64编码格式<br/> * 由于非对称加密速度极其缓慢，一般文件不使用它来加密而是使用对称加密，<br/> * 非对称加密算法可以用来对对称加密的密钥加密，这样保证密钥的安全也就保证了数据的安全 * </p> *  */public class RSAUtils{   /**   * 加密算法RSA   */  public static final String KEY_ALGORITHM = "RSA";     /**   * 签名算法   */  public static final String SIGNATURE_ALGORITHM = "MD5withRSA";   /**   * 获取公钥的key   */  private static final String PUBLIC_KEY = "LocatorPublicKey";     /**   * 获取私钥的key   */  private static final String PRIVATE_KEY = "LocatorPrivateKey";     /**   * RSA最大加密明文大小   */  private static final int MAX_ENCRYPT_BLOCK = 117;     /**   * RSA最大解密密文大小   */  private static final int MAX_DECRYPT_BLOCK = 128;   /**   * <p>   * 生成密钥对(公钥和私钥)   * </p>   *    * @return   * @throws Exception   */  public static Map<String, Object> genKeyPair() throws Exception {    KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance(KEY_ALGORITHM);    keyPairGen.initialize(1024);    KeyPair keyPair = keyPairGen.generateKeyPair();    RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();    RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();    Map<String, Object> keyMap = new HashMap<String, Object>(2);    keyMap.put(PUBLIC_KEY, publicKey);    keyMap.put(PRIVATE_KEY, privateKey);    return keyMap;  }     /**   * <p>   * 用私钥对信息生成数字签名   * </p>   *    * @param data 已加密数据   * @param privateKey 私钥(BASE64编码)   *    * @return   * @throws Exception   */  public static String sign(byte[] data, String privateKey) throws Exception {    byte[] keyBytes = Base64Utils.decode(privateKey);    PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);    KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);    PrivateKey privateK = keyFactory.generatePrivate(pkcs8KeySpec);    Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);    signature.initSign(privateK);    signature.update(data);    return Base64Utils.encode(signature.sign());  }   /**   * <p>   * 校验数字签名   * </p>   *    * @param data 已加密数据   * @param publicKey 公钥(BASE64编码)   * @param sign 数字签名   *    * @return   * @throws Exception   *    */  public static boolean verify(byte[] data, String publicKey, String sign)      throws Exception {    byte[] keyBytes = Base64Utils.decode(publicKey);    X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes);    KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);    PublicKey publicK = keyFactory.generatePublic(keySpec);    Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);    signature.initVerify(publicK);    signature.update(data);    return signature.verify(Base64Utils.decode(sign));  }   /**   * <P>   * 私钥解密   * </p>   *    * @param encryptedData 已加密数据   * @param privateKey 私钥(BASE64编码)   * @return   * @throws Exception   */  public static byte[] decryptByPrivateKey(byte[] encryptedData, String privateKey)      throws Exception {    byte[] keyBytes = Base64Utils.decode(privateKey);    PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);    KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);    Key privateK = keyFactory.generatePrivate(pkcs8KeySpec);    Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());    cipher.init(Cipher.DECRYPT_MODE, privateK);    int inputLen = encryptedData.length;    ByteArrayOutputStream out = new ByteArrayOutputStream();    int offSet = 0;    byte[] cache;    int i = 0;    // 对数据分段解密    while (inputLen - offSet > 0) {      if (inputLen - offSet > MAX_DECRYPT_BLOCK) {        cache = cipher.doFinal(encryptedData, offSet, MAX_DECRYPT_BLOCK);      } else {        cache = cipher.doFinal(encryptedData, offSet, inputLen - offSet);      }      out.write(cache, 0, cache.length);      i++;      offSet = i * MAX_DECRYPT_BLOCK;    }    byte[] decryptedData = out.toByteArray();    out.close();    return decryptedData;  }   /**   * <p>   * 公钥解密   * </p>   *    * @param encryptedData 已加密数据   * @param publicKey 公钥(BASE64编码)   * @return   * @throws Exception   */  public static byte[] decryptByPublicKey(byte[] encryptedData, String publicKey)      throws Exception {    byte[] keyBytes = Base64Utils.decode(publicKey);    X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes);    KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);    Key publicK = keyFactory.generatePublic(x509KeySpec);    Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());    cipher.init(Cipher.DECRYPT_MODE, publicK);    int inputLen = encryptedData.length;    ByteArrayOutputStream out = new ByteArrayOutputStream();    int offSet = 0;    byte[] cache;    int i = 0;    // 对数据分段解密    while (inputLen - offSet > 0) {      if (inputLen - offSet > MAX_DECRYPT_BLOCK) {        cache = cipher.doFinal(encryptedData, offSet, MAX_DECRYPT_BLOCK);      } else {        cache = cipher.doFinal(encryptedData, offSet, inputLen - offSet);      }      out.write(cache, 0, cache.length);      i++;      offSet = i * MAX_DECRYPT_BLOCK;    }    byte[] decryptedData = out.toByteArray();    out.close();    return decryptedData;  }   /**   * <p>   * 公钥加密   * </p>   *    * @param data 源数据   * @param publicKey 公钥(BASE64编码)   * @return   * @throws Exception   */  public static byte[] encryptByPublicKey(byte[] data, String publicKey)      throws Exception {    byte[] keyBytes = Base64Utils.decode(publicKey);    X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes);    KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);    Key publicK = keyFactory.generatePublic(x509KeySpec);    // 对数据加密    Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());    cipher.init(Cipher.ENCRYPT_MODE, publicK);    int inputLen = data.length;    ByteArrayOutputStream out = new ByteArrayOutputStream();    int offSet = 0;    byte[] cache;    int i = 0;    // 对数据分段加密    while (inputLen - offSet > 0) {      if (inputLen - offSet > MAX_ENCRYPT_BLOCK) {        cache = cipher.doFinal(data, offSet, MAX_ENCRYPT_BLOCK);      } else {        cache = cipher.doFinal(data, offSet, inputLen - offSet);      }      out.write(cache, 0, cache.length);      i++;      offSet = i * MAX_ENCRYPT_BLOCK;    }    byte[] encryptedData = out.toByteArray();    out.close();    return encryptedData;  }   /**   * <p>   * 私钥加密   * </p>   *    * @param data 源数据   * @param privateKey 私钥(BASE64编码)   * @return   * @throws Exception   */  public static byte[] encryptByPrivateKey(byte[] data, String privateKey)      throws Exception {    byte[] keyBytes = Base64Utils.decode(privateKey);    PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);    KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);    Key privateK = keyFactory.generatePrivate(pkcs8KeySpec);    Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());    cipher.init(Cipher.ENCRYPT_MODE, privateK);    int inputLen = data.length;    ByteArrayOutputStream out = new ByteArrayOutputStream();    int offSet = 0;    byte[] cache;    int i = 0;    // 对数据分段加密    while (inputLen - offSet > 0) {      if (inputLen - offSet > MAX_ENCRYPT_BLOCK) {        cache = cipher.doFinal(data, offSet, MAX_ENCRYPT_BLOCK);      } else {        cache = cipher.doFinal(data, offSet, inputLen - offSet);      }      out.write(cache, 0, cache.length);      i++;      offSet = i * MAX_ENCRYPT_BLOCK;    }    byte[] encryptedData = out.toByteArray();    out.close();    return encryptedData;  }   /**   * <p>   * 获取私钥   * </p>   *    * @param keyMap 密钥对   * @return   * @throws Exception   */  public static String getPrivateKey(Map<String, Object> keyMap)      throws Exception {    Key key = (Key) keyMap.get(PRIVATE_KEY);    return Base64Utils.encode(key.getEncoded());  }   /**   * <p>   * 获取公钥   * </p>   *    * @param keyMap 密钥对   * @return   * @throws Exception   */  public static String getPublicKey(Map<String, Object> keyMap)      throws Exception {    Key key = (Key) keyMap.get(PUBLIC_KEY);    return Base64Utils.encode(key.getEncoded());  } }