Encrypt and decrypt a string in android

Hi I want to encrypt a string in android inorder to store and later for showing I have to decrypt it. Is it possible to do md5 hashing or any开发者_如何学Go other hashing in android. Please provide me an example.

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The javax.crypto package does everything you need

http://developer.android.com/reference/javax/crypto/package-summary.html

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android.util.Base64 encoding is good enough if you want to store something e.g. in a share preferences file:

Here is what I do:

Storing:

public void saveSomeText (String text) {
    SharedPreferences.Editor editor = prefs.edit();
    if (Utils.isEmpty( text ))
        text = null;
    else
        text = Base64.encodeToString( text.getBytes(), Base64.DEFAULT );
    editor.putString( "some_text", text );
    editor.commit();
}

Retrieval:

public String getSomeText () {
    String text = prefs.getString( "some_text", null );
    if (!Utils.isEmpty( passwd )) {
        text = new String( Base64.decode( text, Base64.DEFAULT ) );
    }
    return text;
}

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Use MAHEncryptorLibrary

Sample:

• For encryption

  MAHEncryptor mahEncryptor = MAHEncryptor.newInstance("This is sample SecretKeyPhrase");
  String encrypted = mahEncryptor.encode("This is MAHEncryptorLib java sample");
  

• For decryption

  MAHEncryptor mahEncryptor = MAHEncryptor.newInstance("This is sample SecretKeyPhrase");
  String decrypted = mahEncryptor.decode("4Vi86K/JL9gKclQahacrKLrEZL6/0vOpS4yPVm1hSLhhDsCMJTyd4A==");
  

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When You want to encrypt a string on one side and decrypt it on other side the use this code its working good.Just copy this code and run in you eclipse, it will solve your problem

Encryption Method for String

    final int shift_key = 4; //it is the shift key to move charcter, like if i have 'a' then a=97+4=101 which =e and thus it changes
    String plainText = "adhami piran"; 
    char character; 
     char ch[]=new char[plainText.length()];//for storing encrypt char
   for (int iteration = 0; iteration < plainText.length(); iteration++)
            {
                    character = plainText.charAt(iteration); //get characters
                    character = (char) (character + shift_key); //perform shift
              }     ch[iteration]=character;//assign char to char array
     String encryptstr = String.valueOf(ch);//converting char array to string
     Toast.makeText(this, "Encrypt string is "+ encryptstr Toast.LENGTH_LONG).show();

Decrypting Method for String

   for(int i=0;i<encryptstr.length();i++)
     {
        character=str.charAt(i);
        character = (char) (character -shift_key); //perform shift
            ch[i]=character;
     }
 Stirng decryptstr = String.valueOf(ch);
     Toast.makeText(this, "Decrypted String is "+decryptstr, Toast.LENGTH_LONG).show();

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Read this article here->(How_to_encrypt_and_decrypt_strings.rhtml). It is pretty much what you want. The technique there uses .getInstance("AES"); If you want MD5 just replaces the AES with MD5.