java - BadPaddingException when decrypting using a different Cipher object -

please excuse hackjob! still new @ coding , utilizing lot of sys outs troubleshoot, , first post @ stackoverflow. thank help!

so i've been working on trying encrypt string objects using javax.crypto.cipher api, , have found success, when using same instance of cipher object. however, purposes of project, encrypting text (string) , decrypting text text file, , not accessing same cipher object every time.

i believe issue not converting between byte arrays , strings, since base64 encoder seems have taken care of problem. output of byte arrays identical pre-encoding , post-decoding, should isolate issue during decryption phase. can done decryptpw method can use different cipher instance (with same arguments passed) , not trigger badpaddingexception?

private static string encryptpw(string pw){     byte[] pwbytes = pw.getbytes();     byte[] keybytes = "0123456789abcdef".getbytes();     secretkeyspec keyspec = new secretkeyspec(keybytes, "aes");     try {         cipher ciph = cipher.getinstance("aes/cbc/pkcs5padding");         ciph.init(cipher.encrypt_mode, keyspec);         byte[] encryptedbytes = ciph.dofinal(pwbytes);         pw = base64.getencoder().encodetostring(ciph.dofinal(pwbytes));          (byte b : encryptedbytes){             system.out.print(b);         }         system.out.println();     } catch (exception e){         e.printstacktrace();     }     return pw; }  private static string decryptpw(string pw){     byte[] pwbytes = base64.getdecoder().decode(pw.getbytes());     (byte b : pwbytes){         system.out.print(b);     }     system.out.println();      byte[] keybytes = "0123456789abcdef".getbytes();     secretkeyspec keyspec = new secretkeyspec(keybytes, "aes");     try {         cipher ciph = cipher.getinstance("aes/cbc/pkcs5padding");         ciph.init(cipher.decrypt_mode, keyspec, ciph.getparameters());         pw = new string(ciph.dofinal(pwbytes));         } catch (exception e){         e.printstacktrace();     }     return pw; } 

again, thank you!

as use cbc mode, need save random initialization vector (iv) encryption cipher , provide decryption cipher.

you can encryption cipher after init like:

ciph.init(cipher.encrypt_mode, keyspec); byte[] iv = ciph.getiv(); 

and provide decrypt cipher like:

ciph.init(cipher.decrypt_mode, keyspec, new ivparameterspec(iv)); 

you need come method of saving iv. common way prefix encrypted data iv, it's available when need initialize decrypt cipher. don't need secret.