[Android] Des/3des/aes Encryption method

DES supports 8-bit encryption decryption, 3Des supports 24-bit, and AES supports 32-bit. 3Des is the DES algorithm to do three times. The number of bits is in bytes byte, not bits.

3Des is divided 24 bits into 3 groups, the first set of eight bits for encryption, the second set of 8 bits for decryption, and the third set of 8 bits for encryption, so if the secret key is 123456781234567812345678 (3 group 1-8), it is equivalent to a 12345678 des encryption. For example: The first time with 12345678 key to 123 encryption to get "ldifudf0iew=", and then use the second set of 12345678 to decrypt it (reverse encryption process), get 123, the third time encryption to get "ldifudf0iew=".

There are three different ways of encrypting code:

byte temp[] = new byte[number of digits];

Secretkey Des_key = new Secretkeyspec (temp, "cryptographic algorithm");

The encryption algorithm name corresponds to: Aes Des Desede

You can implement different encryption methods by changing these two places. Encryption method is not the same as the bottom, DES is the original programming 2 into a string of 01, and then the cipher to do the operation, Exchange what position.

<span style= "FONT-SIZE:18PX;" >public class Mainactivity extends Activity implements Onclicklistener{private EditText des_key,des_src,des_dst;    Private Button Btn_encode,btn_decode;        @Override protected void OnCreate (Bundle savedinstancestate) {super.oncreate (savedinstancestate);        Setcontentview (R.layout.activity_main);        Des_key = (EditText) Findviewbyid (R.id.des_key);        DES_SRC = (EditText) Findviewbyid (R.ID.DES_SRC);        DES_DST = (EditText) Findviewbyid (R.ID.DES_DST);        Btn_encode = (Button) Findviewbyid (R.id.btn_encode);        Btn_decode = (Button) Findviewbyid (R.id.btn_decode);        Btn_encode.setonclicklistener (this);    Btn_decode.setonclicklistener (this); } @Overridepublic void OnClick (View v) {String key_str = Des_key.gettext (). toString (); Textutils.isempty (KEY_STR)) {try {//des no matter how short it is, it becomes eight bits byte temp[] = new Byte[8];byte b[] = key_str.getbytes ("UTF-8"); System.arraycopy (b, 0, temp, 0, math.min (b.length, temp.length));//des only supports eightBit Secretkey Des_key = new Secretkeyspec (temp, "des"); Cipher Cipher = cipher.getinstance ("Des"), switch (V.getid ()) {case R.id.btn_encode:string src_str = Des_src.gettext (). ToString (); if (! Textutils.isempty (SRC_STR)) {Cipher.init (Cipher.encrypt_mode, Des_key);//Set cipher for encryption byte[] bytes = cipher.dofinal ( Src_str.getbytes ("UTF-8"));d es_dst.settext (base64.encodetostring (bytes, base64.default)); </span><pre Name= "Code" class= "java" ><span style= "font-size:18px;" >//is a binary byte array encoded with BASE64 </span>

}break;case r.id.btn_decode:string dst_str = Des_dst.gettext (). toString (); Textutils.isempty (DST_STR)) {Cipher.init (Cipher.decrypt_mode, Des_key);//Set cipher to decrypt byte[] bytes = cipher.dofinal ( Base64.decode (Dst_str, Base64.default));//is a binary byte array des_src.settext encoded with Base64 (new String (bytes, "UTF-8"));} Break;}} catch (Exception e) {e.printstacktrace ();}}}}

layout:

<span style= "FONT-SIZE:18PX;" ><linearlayout xmlns:android= "http://schemas.android.com/apk/res/android" xmlns:tools= "http// Schemas.android.com/tools "android:layout_width=" match_parent "android:layout_height=" Match_parent "Android:orien        tation= "vertical" > <edittext android:id= "@+id/des_key" android:layout_width= "Wrap_content"        android:layout_height= "Wrap_content" android:hint= "secret key"/> <edittext android:id= "@+id/des_src" Android:layout_width= "Wrap_content" android:layout_height= "Wrap_content" android:hint= "original"/> <Ed Ittext android:id= "@+id/des_dst" android:layout_width= "wrap_content" android:layout_height= "Wrap_cont Ent "android:hint=" ciphertext "/> <button android:id=" @+id/btn_encode "android:layout_width=" Wrap_co Ntent "android:layout_height=" wrap_content "android:text=" Encrypt "/> <button android:id=" @+id/bt  N_decode "      Android:layout_width= "Wrap_content" android:layout_height= "wrap_content" android:text= "decryption"/></L Inearlayout></span>

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[Android] Des/3des/aes Encryption method