Architecture

Stoffel VM is a register based virtual machine with two sets of registers. Clear registers for manipulating non-secret values. Secret registers are used for manipulating secret values.

Why a Register Machine?

The choice of a register-based architecture over a stack-based design was driven by several key factors:

1. Parallelization Opportunities

   • Register machines allow for easier identification of independent instructions
   • Multiple instructions can be executed in parallel, reducing overall execution time
   • Better suited for modern hardware architectures

2. Communication Efficiency

   • Reduced number of memory access operations
   • Fewer rounds of communication in Multi-Party Computation (MPC) contexts
   • More efficient instruction encoding

3. Optimization Potential

   • Direct access to operands enables better optimization strategies
   • Easier to implement specialized instructions
   • More straightforward analysis of data flow

Why dedicated clear and secret registers

1. Implicit reveal and hide
   • Having dedicated registers for secret and clear values allows us to implicitly reveal and hide values as they're moved between registers.
   • Separation of registers allows for optimizations to be applied specifically to clear or secret operations.
   • Avoids having to track the type of the virtual register during runtime as values may become secret shared or reveal through the course of execution.