To protect the minimal application, first make a copy of the minimal directory somewhere you have write access. From the copied minimal directory, run the following command:

This tells the translator to transform classes found under the classes directory, put the modified classes under the sclasses directory, and put disassembled listings of the class files before and after transformation under the dasm directory. These and other options are described in more details in Section 3, “Running the Tools”.

Under the dasm directory, two subdirectories input and output contain a listing of the bytecode for the Minimal class, before and after the transformation. By comparing these files, it is possible to see that the counter field and its annotation has been replaced by another field that holds a pointer to the secure coprocessor memory.

  // access flags 2
  private I counter
  @Lcom/validy/technology/annotation/SecureField;() // invisible

is transformed into

  // access flags 4114
  private final Lcom/validy/technology/runtime/Memory; k$This

The inc method increments the counter field by one. The instruction IADD performs this operation in the original bytecode below.

  // access flags 1
  public inc()V
  @Lcom/validy/technology/annotation/SecureMethod;() // invisible
    ALOAD 0
    DUP
    GETFIELD Minimal.counter : I
    ICONST_1
    IADD
    PUTFIELD Minimal.counter : I
    RETURN

In the transformed bytecode, the instructions that manipulate the counter field have been converted to be executed by the secure coprocessor virtual machine. In the bytecode below, these instructions appear as calls to a method from the Validy Technology runtime that receive a long constant - the ciphered instruction - as parameter.

  // access flags 1
  public inc()V
  @Lcom/validy/technology/annotation/SecureMethod;() // invisible
    LDC -1871519230529205310
    INVOKESTATIC com/validy/technology/runtime/Token.exe (J)V
    LDC 5960922510504744152
    INVOKESTATIC com/validy/technology/runtime/Token.exe (J)V
    LDC 2237779730922682514
    INVOKESTATIC com/validy/technology/runtime/Token.exe (J)V
    LDC -2778962704774231912
    INVOKESTATIC com/validy/technology/runtime/Token.exe (J)V
    LDC 8090141189977720929
    INVOKESTATIC com/validy/technology/runtime/Token.exe (J)V
    LDC 8491204469737689782
    INVOKESTATIC com/validy/technology/runtime/Token.exe (J)V
    RETURN

Because the minimal application is very small, all instructions have been selected to be executed by the secure coprocessor and the size of the class file more than doubles. In a more complex application, only a relatively small fraction of the instructions will be converted.