Are there any tools for expressing the cipher operations as a system of equations? The first step In Algebraic-attack is expressing the cipher operations as a system of equations. Is there an automated tool to do this?
Theoretically, the equations could be derived from the representation of the cipher in a hardware description language like VHDL or Verilog; you implement the cipher as if you want to make a FPGA/ASIC which runs it, but you stop at the symbolic representation of the logic gates (the "netlist"). However, I am not aware of any existing conversion tool which will transform a netlist into a sequence of equations in the right format for whatever equation solver you want to use for performing the attack.