Java AES CBC Fill method Discovery

such as the Java code, after the block is manually populated, so that it is an integer multiple of 16, when the encryption is forced to fill the 16-bit, I am trying to use Golang implementation of this encryption, repeated changes for a long time, found that the Golang version is always more than the Java encryption and Base64 results less than 20 bits, so the results of each step in the middle of the fight out, found that there is no difference, and then try to force the Golang after the addition of 16 padding, then fill what? Yes, I was from 0x0 to 0x10 a try out, and finally found that when filled with 16 0x10, Golang and Java encryption results are exactly the same, the following paste Golang and Java two code:

Ps:iv and key are identical. Get a lesson, when Golang and Java under the two same patterns, if the encrypted ciphertext is different, try to modify the method of filling, it is always possible to try a few more times.

Java:

 Public StaticString AesEncrypt2 (String Appsecret, String data)throwsException {//setting the encryption keyString key = appsecret.substring (16);        SYSTEM.OUT.PRINTLN (key); Secretkeyspec Keyspec=NewSecretkeyspec (Key.getbytes (), "AES"); //initialization VectorSYSTEM.OUT.PRINTLN ("MD5:" + Digestutils.md5hex (Appsecret). substring (0, 16)); String IV= Digestutils.md5hex (Appsecret). substring (0, 16); Ivparameterspec Ivspec=NewIvparameterspec (Iv.getbytes ()); //Setting the encryption modeCipher Cipher = cipher.getinstance ("aes/cbc/pkcs5padding"); //Fill Algorithm        intBlockSize =cipher.getblocksize (); byte[] Databytes =data.getbytes (); intPlaintextlength =databytes.length; if(plaintextlength% BlockSize! = 0) {Plaintextlength= Plaintextlength + (blockSize-(plaintextlength%blockSize)); }        byte[] plaintext =New byte[Plaintextlength]; System.arraycopy (Databytes,0, plaintext, 0, databytes.length); System.out.println ("Padding after length =" +plaintext.length);  for(inti = 0;i < plaintext.length; i++) System.out.print (Plaintext[i]+ " "); //EncryptCipher.init (Cipher.encrypt_mode, Keyspec, Ivspec); byte[] encrypted =cipher.dofinal (plaintext); System.out.println ("");  for(inti = 0;i < encrypted.length;i++) System.out.print (Encrypted[i]+ " "); System.out.println (""); returnbase64.encodebase64string (encrypted); }

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Golang:

Func GetMD5 (ciphertextstring)string{md5ctx:=MD5. New () Md5ctx.write ([]byte(ciphertext)) Cipherstr:=md5ctx.sum (Nil)returnHex. Encodetostring (CIPHERSTR)}func pkcs5padding (ciphertext []byte, blockSizeint) []byte{padding:= Blocksize-len (ciphertext)%blockSize//padtext: = bytes. Repeat ([]byte{byte (padding)}, padding)     forI: =0; i < padding; i++{ciphertext= Append (Ciphertext,0x0)    }     forI: = -; I < +; i++{ciphertext= Append (Ciphertext,0x10)} FMT. Println (ciphertext) fmt. Printf ("blocksieze[%d]\n", Len (ciphertext))//return Append (ciphertext, padtext ...)    returnCiphertext}func Aesencrypt (Secret, datastring)string {    ifLen (Secret) < -{log. Errorf ("aesencrypt secret[%s] length less")        return ""} fmt. Println (secret[ -:]) Key:= []byte(secret[ -:]) IV:= []byte(GetMD5 (Secret) [: -]) fmt. Println ("MD5:"+ GetMD5 (Secret) [: -]) block, err:=AES. Newcipher (Key)ifErr! =Nil {log. Errorf ("Key Error[%v]", Err)return ""} ECB:=cipher. Newcbcencrypter (block, iv) content:= Pkcs5padding ([]byte(data), block. BlockSize ()) crypted:= Make ([]byte, Len (content)) ECB. Cryptblocks (crypted, content) fmt. Println (crypted)returnBase64. Stdencoding.encodetostring (crypted)}

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Java AES CBC Fill method Discovery