MacReuseTest (crypto-testsuite 2.3.0 API)

java.lang.Object
- com.microej.crypto.test.MacReuseTest

```
public class MacReuseTest
extends java.lang.Object
```
Checks that a Mac is usable again after doFinal() without being re-initialized.
javax.crypto.Mac specifies that doFinal() leaves the object reset and ready for another message with the same key. Nothing exercised that: every MAC in the rest of the suite is computed by a freshly initialized object, so the reset the backend performs between messages has its effect discarded every time and a reset that keeps the buffered bytes, or leaves the context unusable, is not caught.
The expected values are the published RFC 2202 and RFC 4231 vectors, so a wrong result is wrong against the standard rather than against a previous run.
Mac.reset() is deliberately never called here. Reuse after doFinal() is the path the specification promises and the one an application takes; calling reset() explicitly would suggest the backend reset is being driven directly, which it is not.

Constructor Summary

Constructors
Constructor Description

MacReuseTest()

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`void`	`testDifferentSecondMessageWithoutReinit()`	A different second message through the same object gives that message's MAC.
`void`	`testReusedMacFedInTwoParts()`	Feeding the reused object through `update()` before `doFinal()` gives the same MAC as one call.
`void`	`testSameMessageTwiceWithoutReinit()`	The same message twice through one object gives the same MAC twice.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - MacReuseTest
```
public MacReuseTest()
```
- Method Detail
  - testSameMessageTwiceWithoutReinit
```
public void testSameMessageTwiceWithoutReinit()
                                       throws java.lang.Exception
```
    The same message twice through one object gives the same MAC twice.
    A reset that leaves the previous message buffered gives a different second value.
    
    Throws:
    
    java.lang.Exception
  - testDifferentSecondMessageWithoutReinit
```
public void testDifferentSecondMessageWithoutReinit()
                                             throws java.lang.Exception
```
    A different second message through the same object gives that message's MAC.
    Repeating one message cannot tell a correct reset from one that reproduces the previous state; a second message can. The key is longer than the block size, so the object also has to keep the hashed key across doFinal().
    
    Throws:
    
    java.lang.Exception
  - testReusedMacFedInTwoParts
```
public void testReusedMacFedInTwoParts()
                                throws java.lang.Exception
```
    Feeding the reused object through update() before doFinal() gives the same MAC as one call.
    This is the ordering that fails when the reset happens on the first update() after doFinal() rather than at doFinal() itself: the first fragment is discarded and the MAC covers only the rest.
    
    Throws:
    
    java.lang.Exception