android - Encryption failed in Marshmallow -

i trying encrypt , decrypt data sd card tried oon code , working proper in lower version devices getting 1 exception in marshmallow.

  04-19 09:56:50.428: w/system.err(15137): javax.crypto.badpaddingexception: pad block corrupted   04-19 09:56:50.432: w/system.err(15137):  @ com.android.org.bouncycastle.jcajce.provider.symmetric.util.baseblockcipher$bufferedgenericblockcipher.dofinal(baseblockcipher.java:1011)   04-19 09:56:50.432: w/system.err(15137):  @ com.android.org.bouncycastle.jcajce.provider.symmetric.util.baseblockcipher.enginedofinal(baseblockcipher.java:849)   04-19 09:56:50.432: w/system.err(15137):  @ javax.crypto.cipher.dofinal(cipher.java:1502)   04-19 09:56:50.432: w/system.err(15137):  @ com.example.encryptaudio.cryptofile.decrypt(cryptofile.java:34)   04-19 09:56:50.432: w/system.err(15137):  @ com.example.encryptaudio.mainactivity$2.onclick(mainactivity.java:116)   04-19 09:56:50.432: w/system.err(15137):  @ android.view.view.performclick(view.java:5201)   04-19 09:56:50.432: w/system.err(15137):  @ android.view.view$performclick.run(view.java:21163)   04-19 09:56:50.432: w/system.err(15137):  @ android.os.handler.handlecallback(handler.java:746)   04-19 09:56:50.432: w/system.err(15137):  @ android.os.handler.dispatchmessage(handler.java:95)   04-19 09:56:50.432: w/system.err(15137):  @ android.os.looper.loop(looper.java:148)   04-19 09:56:50.432: w/system.err(15137):  @ android.app.activitythread.main(activitythread.java:5443)   04-19 09:56:50.432: w/system.err(15137):  @ java.lang.reflect.method.invoke(native method)   04-19 09:56:50.432: w/system.err(15137):  @ com.android.internal.os.zygoteinit$methodandargscaller.run(zygoteinit.java:728) 

the code following encryption

cryptofile simplecrypto = new cryptofile();                  try {      // encrypt audio file send second argument , corresponding key in first argument.        incrept = simplecrypto.encrypt(key, getaudiofile());                           //store encrypted file in sd card of mobile name vincent.mp3.        fileoutputstream fos = new fileoutputstream(new file("/sdcard/vincent.mp3"));             fos.write(incrept);             fos.close();    } catch (exception e) {        e.printstacktrace();   }  } 

decryption

cryptofile simplecrypto = new cryptofile();                     try {      // decrypt file here first argument key , second encrypted file sd card.     decrpt = simplecrypto.decrypt(key, getaudiofilefromsdcard()); //play decrypted audio file.     playmp3(decrpt);                       } catch (exception e) {      e.printstacktrace();  } } 

crypt.java

public class cryptofile {  public  byte[] encrypt(string seed, byte[] cleartext) throws exception {                     byte[] rawkey = getrawkey(seed.getbytes());      byte[] result = encrypt(rawkey, cleartext);    //  return tohex(result);     return result; }  public  byte[] decrypt(string seed, byte[] encrypted) throws exception {      byte[] rawkey = getrawkey(seed.getbytes());      byte[] enc = encrypted;      byte[] result = decrypt(rawkey, enc);       return result;     }  //done  private  byte[] getrawkey(byte[] seed) throws exception {      keygenerator kgen = keygenerator.getinstance("aes");      securerandom sr = securerandom.getinstance("sha1prng");      sr.setseed(seed);  kgen.init(128, sr); // 192 , 256 bits may not available  secretkey skey = kgen.generatekey();  byte[] raw = skey.getencoded();  return raw; } private  byte[] encrypt(byte[] raw, byte[] clear) throws exception {  secretkeyspec skeyspec = new secretkeyspec(raw, "aes");      cipher cipher = cipher.getinstance("aes");  cipher.init(cipher.encrypt_mode, skeyspec);  byte[] encrypted = cipher.dofinal(clear);      return encrypted;  }   private  byte[] decrypt(byte[] raw, byte[] encrypted) throws exception {  secretkeyspec skeyspec = new secretkeyspec(raw, "aes");      cipher cipher = cipher.getinstance("aes");  cipher.init(cipher.decrypt_mode, skeyspec);  byte[] decrypted = cipher.dofinal(encrypted);      return decrypted;  }  } 

aes keys should consist of random data. if store them string loose information. not specify encoding type either in encryption or decryption.

encryption

 encryptedtext = c.dofinal(cleartext.getbytes("utf-8"));  return base64.encodetostring(encryptedtext, base64.default); 

decryption

cleartext = c.dofinal(base64.decode(encryptedtext, base64.default)); return new string(cleartext, "utf-8");