fr.maxcom.http

Interface CipherFactory

public interface CipherFactory

Interface for a cipher factory. For transformations allowing a random access to the data, you should implement a factory and give it to the server with the setCipherFactory() method.

Method Summary

Modifier and Type	Method and Description
Cipher	getCipher() Returns the initial cipher, that is with the initial IV.
Cipher	rebaseCipher(byte[] iv) Returns a new cipher, created with a computed IV in place of the initial IV.

Method Detail

getCipher

Cipher getCipher()
          throws GeneralSecurityException

Returns the initial cipher, that is with the initial IV.

In case you also use it, setCipher() has precedence over this method, which you can simply implement as returning null. But this is not a recommended design: a better approach is to group all cipher related actions at the same place.

Example of implementation:

// you are free to choose your own Initialization Vector
byte[] initialIV = new byte[16];
return rebaseCipher(initialIV);
 

Returns:

An initial cipher.

Throws:

GeneralSecurityException - If the object cannot be created.

rebaseCipher

Cipher rebaseCipher(byte[] iv)
             throws GeneralSecurityException

Returns a new cipher, created with a computed IV in place of the initial IV.

Example of implementation:

// avoid the default security provider "AndroidOpenSSL" in Android 4.3+
Cipher c = Cipher.getInstance("AES/CTR/NoPadding", "BC");
c.init(Cipher.DECRYPT_MODE,
    new SecretKeySpec("1234567890123456".getBytes(), "AES"),
    new IvParameterSpec(iv));
return c;
 

Parameters:

iv - The computed IV to consider.

Returns:

A new cipher.

Throws:

GeneralSecurityException - If the object cannot be created.