Android使用KeyStore对数据进行加密的示例代码

public String encryptString(String needEncryptWord, String alias) {
    if(!"".equals(alias)&&!"".equals(needEncryptWord)){
      if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR2) {
        initKeyStore(alias);
      }
      String encryptStr="";
      byte [] vals=null;
      try {
        KeyStore.PrivateKeyEntry privateKeyEntry = (KeyStore.PrivateKeyEntry)keyStore.getEntry(alias, null);
//      RSAPublicKey publicKey = (RSAPublicKey) privateKeyEntry.getCertificate().getPublicKey();
        if(needEncryptWord.isEmpty()) {
//        Toast.makeText(this, "Enter text in the 'Initial Text' widget", Toast.LENGTH_LONG).show();
          return encryptStr;
        }

//      Cipher inCipher = Cipher.getInstance("RSA/ECB/PKCS1Padding", "AndroidOpenSSL");
        Cipher inCipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");
//      inCipher.init(Cipher.ENCRYPT_MODE, publicKey);
        inCipher.init(Cipher.ENCRYPT_MODE, privateKeyEntry.getCertificate().getPublicKey());

        ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
        CipherOutputStream cipherOutputStream = new CipherOutputStream(
            outputStream, inCipher);
        cipherOutputStream.write(needEncryptWord.getBytes("UTF-8"));
        cipherOutputStream.close();

        vals = outputStream.toByteArray();
      } catch (Exception e) {
        e.printStackTrace();
      }
      return Base64.encodeToString(vals, Base64.DEFAULT);
    }
    return "";
  }

public String decryptString(String needDecryptWord, String alias) {
    if(!"".equals(alias)&&!"".equals(needDecryptWord)){
      if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR2) {
        initKeyStore(alias);
      }
      String decryptStr="";
      try {
        KeyStore.PrivateKeyEntry privateKeyEntry = (KeyStore.PrivateKeyEntry)keyStore.getEntry(alias, null);
//      RSAPrivateKey privateKey = (RSAPrivateKey) privateKeyEntry.getPrivateKey();

//      Cipher output = Cipher.getInstance("RSA/ECB/PKCS1Padding", "AndroidOpenSSL");
        Cipher output = Cipher.getInstance("RSA/ECB/PKCS1Padding");
//      output.init(Cipher.DECRYPT_MODE, privateKey);
        output.init(Cipher.DECRYPT_MODE, privateKeyEntry.getPrivateKey());
        CipherInputStream cipherInputStream = new CipherInputStream(
            new ByteArrayInputStream(Base64.decode(needDecryptWord, Base64.DEFAULT)), output);
        ArrayList<Byte> values = new ArrayList<>();
        int nextByte;
        while ((nextByte = cipherInputStream.read()) != -1) {
          values.add((byte)nextByte);
        }

        byte[] bytes = new byte[values.size()];
        for(int i = 0; i < bytes.length; i++) {
          bytes[i] = values.get(i).byteValue();
        }

        decryptStr = new String(bytes, 0, bytes.length, "UTF-8");
      } catch (Exception e) {
        e.printStackTrace();
      }
      return decryptStr;
    }
    return "";
  }