Android to obtain the signature public key and the private key encryption method (recommended)

Updated: December 15, 2016 15:47:12 Submission: jingxian

Below, the editor will bring you an article about how to obtain the signature public key and the private key of the public key in Android (recommended). The editor thinks it is quite good, so I will share it with you now and give you a reference. Let's take a look with the editor

As shown below:

public class GetPublicKey {
   
  /**
    * Get the signature public key
    * @param mContext
    * @return
    */
  protected static String getSignInfo(Context mContext) {
    String signcode = "";
    try {
      PackageInfo packageInfo = ().getPackageInfo(
          (mContext), PackageManager.GET_SIGNATURES);
      Signature[] signs = ;
      Signature sign = signs[0];
 
      signcode = parseSignature(());
      signcode = ();
    } catch (Exception e) {
      (, (), 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 = ().toString();
      String ss = subString(pubKey);
      ss = (",", "");
      ss = ();
      int aa = ("modulus");
      int bb = ("publicexponent");
      sign = (aa + 8, bb);
    } catch (CertificateException e) {
      (, (), e);
    }
    return sign;
  }
 
  public static String subString(String sub) {
    Pattern pp = ("\\s*|\t|\r|\n");
    Matcher mm = (sub);
    return ("");
  }
}



package ;
 
import ;
import ;
import ;
import ;
import ;
import ;
import ;
import ;
import ;
import ;
import .PKCS8EncodedKeySpec;
import .X509EncodedKeySpec;
import ;
import ;

import ;
 
/**
  * <p>
  * RSA public key/private key/signature toolkit
  * <p>
  * The keys in string format are in BASE64 encoding format without special description<br/>
  * Due to the extremely slow asymmetric encryption speed, generally files do not use it to encrypt but use symmetric encryption,<br/>
  * Asymmetric encryption algorithm can be used to encrypt symmetrically encrypted keys, so as to ensure the security of the keys and ensure the security of the data.
  * </p>
  *
  */
public class RSAUtils{
 
  /**
    * Encryption algorithm RSA
    */
  public static final String KEY_ALGORITHM = "RSA";
   
  /**
    * Signature Algorithm
    */
  public static final String SIGNATURE_ALGORITHM = "MD5withRSA";
 
  /**
    * Get the key of the public key
    */
  private static final String PUBLIC_KEY = "LocatorPublicKey";
   
  /**
    * Get the key of the private key
    */
  private static final String PRIVATE_KEY = "LocatorPrivateKey";
   
  /**
    * RSA maximum encryption plaintext size
    */
  private static final int MAX_ENCRYPT_BLOCK = 117;
   
  /**
    * RSA maximum decrypted ciphertext size
    */
  private static final int MAX_DECRYPT_BLOCK = 128;
 
  /**
    * <p>
    * Generate key pairs (public and private keys)
    * </p>
    *
    * @return
    * @throws Exception
    */
  public static Map&lt;String, Object&gt; genKeyPair() throws Exception {
    KeyPairGenerator keyPairGen = (KEY_ALGORITHM);
    (1024);
    KeyPair keyPair = ();
    RSAPublicKey publicKey = (RSAPublicKey) ();
    RSAPrivateKey privateKey = (RSAPrivateKey) ();
    Map&lt;String, Object&gt; keyMap = new HashMap&lt;String, Object&gt;(2);
    (PUBLIC_KEY, publicKey);
    (PRIVATE_KEY, privateKey);
    return keyMap;
  }
   
  /**
    * <p>
    * Use private key to generate digital signatures
    * </p>
    *
    * @param data Encrypted data
    * @param privateKey private key (BASE64 encoding)
    *
    * @return
    * @throws Exception
    */
  public static String sign(byte[] data, String privateKey) throws Exception {
    byte[] keyBytes = (privateKey);
    PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
    KeyFactory keyFactory = (KEY_ALGORITHM);
    PrivateKey privateK = (pkcs8KeySpec);
    Signature signature = (SIGNATURE_ALGORITHM);
    (privateK);
    (data);
    return (());
  }
 
  /**
    * <p>
    * Verify digital signature
    * </p>
    *
    * @param data Encrypted data
    * @param publicKey public key (BASE64 encoding)
    * @param sign Digital signature
    *
    * @return
    * @throws Exception
    *
    */
  public static boolean verify(byte[] data, String publicKey, String sign)
      throws Exception {
    byte[] keyBytes = (publicKey);
    X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes);
    KeyFactory keyFactory = (KEY_ALGORITHM);
    PublicKey publicK = (keySpec);
    Signature signature = (SIGNATURE_ALGORITHM);
    (publicK);
    (data);
    return ((sign));
  }
 
  /**
    * <P>
    * Private key decryption
    * </p>
    *
    * @param encryptedData Encrypted data
    * @param privateKey private key (BASE64 encoding)
    * @return
    * @throws Exception
    */
  public static byte[] decryptByPrivateKey(byte[] encryptedData, String privateKey)
      throws Exception {
    byte[] keyBytes = (privateKey);
    PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
    KeyFactory keyFactory = (KEY_ALGORITHM);
    Key privateK = (pkcs8KeySpec);
    Cipher cipher = (());
    (Cipher.DECRYPT_MODE, privateK);
    int inputLen = ;
    ByteArrayOutputStream out = new ByteArrayOutputStream();
    int offSet = 0;
    byte[] cache;
    int i = 0;
    // Decrypt the data in segments    while (inputLen - offSet &gt; 0) {
      if (inputLen - offSet &gt; MAX_DECRYPT_BLOCK) {
        cache = (encryptedData, offSet, MAX_DECRYPT_BLOCK);
      } else {
        cache = (encryptedData, offSet, inputLen - offSet);
      }
      (cache, 0, );
      i++;
      offSet = i * MAX_DECRYPT_BLOCK;
    }
    byte[] decryptedData = ();
    ();
    return decryptedData;
  }
 
  /**
    * <p>
    * Public key decryption
    * </p>
    *
    * @param encryptedData Encrypted data
    * @param publicKey public key (BASE64 encoding)
    * @return
    * @throws Exception
    */
  public static byte[] decryptByPublicKey(byte[] encryptedData, String publicKey)
      throws Exception {
    byte[] keyBytes = (publicKey);
    X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes);
    KeyFactory keyFactory = (KEY_ALGORITHM);
    Key publicK = (x509KeySpec);
    Cipher cipher = (());
    (Cipher.DECRYPT_MODE, publicK);
    int inputLen = ;
    ByteArrayOutputStream out = new ByteArrayOutputStream();
    int offSet = 0;
    byte[] cache;
    int i = 0;
    // Decrypt the data in segments    while (inputLen - offSet &gt; 0) {
      if (inputLen - offSet &gt; MAX_DECRYPT_BLOCK) {
        cache = (encryptedData, offSet, MAX_DECRYPT_BLOCK);
      } else {
        cache = (encryptedData, offSet, inputLen - offSet);
      }
      (cache, 0, );
      i++;
      offSet = i * MAX_DECRYPT_BLOCK;
    }
    byte[] decryptedData = ();
    ();
    return decryptedData;
  }
 
  /**
    * <p>
    * Public key encryption
    * </p>
    *
    * @param data Source data
    * @param publicKey public key (BASE64 encoding)
    * @return
    * @throws Exception
    */
  public static byte[] encryptByPublicKey(byte[] data, String publicKey)
      throws Exception {
    byte[] keyBytes = (publicKey);
    X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes);
    KeyFactory keyFactory = (KEY_ALGORITHM);
    Key publicK = (x509KeySpec);
    // Encrypt the data    Cipher cipher = (());
    (Cipher.ENCRYPT_MODE, publicK);
    int inputLen = ;
    ByteArrayOutputStream out = new ByteArrayOutputStream();
    int offSet = 0;
    byte[] cache;
    int i = 0;
    // Encrypt data segmentation    while (inputLen - offSet &gt; 0) {
      if (inputLen - offSet &gt; MAX_ENCRYPT_BLOCK) {
        cache = (data, offSet, MAX_ENCRYPT_BLOCK);
      } else {
        cache = (data, offSet, inputLen - offSet);
      }
      (cache, 0, );
      i++;
      offSet = i * MAX_ENCRYPT_BLOCK;
    }
    byte[] encryptedData = ();
    ();
    return encryptedData;
  }
 
  /**
    * <p>
    * Private key encryption
    * </p>
    *
    * @param data Source data
    * @param privateKey private key (BASE64 encoding)
    * @return
    * @throws Exception
    */
  public static byte[] encryptByPrivateKey(byte[] data, String privateKey)
      throws Exception {
    byte[] keyBytes = (privateKey);
    PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
    KeyFactory keyFactory = (KEY_ALGORITHM);
    Key privateK = (pkcs8KeySpec);
    Cipher cipher = (());
    (Cipher.ENCRYPT_MODE, privateK);
    int inputLen = ;
    ByteArrayOutputStream out = new ByteArrayOutputStream();
    int offSet = 0;
    byte[] cache;
    int i = 0;
    // Encrypt data segmentation    while (inputLen - offSet &gt; 0) {
      if (inputLen - offSet &gt; MAX_ENCRYPT_BLOCK) {
        cache = (data, offSet, MAX_ENCRYPT_BLOCK);
      } else {
        cache = (data, offSet, inputLen - offSet);
      }
      (cache, 0, );
      i++;
      offSet = i * MAX_ENCRYPT_BLOCK;
    }
    byte[] encryptedData = ();
    ();
    return encryptedData;
  }
 
  /**
    * <p>
    * Get the private key
    * </p>
    *
    * @param keyMap key pair
    * @return
    * @throws Exception
    */
  public static String getPrivateKey(Map&lt;String, Object&gt; keyMap)
      throws Exception {
    Key key = (Key) (PRIVATE_KEY);
    return (());
  }
 
  /**
    * <p>
    * Get the public key
    * </p>
    *
    * @param keyMap key pair
    * @return
    * @throws Exception
    */
  public static String getPublicKey(Map&lt;String, Object&gt; keyMap)
      throws Exception {
    Key key = (Key) (PUBLIC_KEY);
    return (());
  }
 
}

The above method of obtaining signature public key and public key private key encryption (recommended) on Android is all the content I share with you. I hope you can give you a reference and I hope you can support me more.

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Public Key
Private key
sign

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Android to obtain the signature public key and the private key encryption method (recommended)

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