sha256_gadget.hpp

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#ifndef SHA256_GADGET_HPP_
#define SHA256_GADGET_HPP_
 
#include <libsnark/common/data_structures/merkle_tree.hpp>
#include <libsnark/gadgetlib1/gadgets/basic_gadgets.hpp>
#include <libsnark/gadgetlib1/gadgets/hashes/hash_io.hpp>
#include <libsnark/gadgetlib1/gadgets/hashes/sha256/sha256_components.hpp>
 
namespace libsnark
{
 
template<typename FieldT>
class sha256_compression_function_gadget : public gadget<FieldT>
{
public:
    std::vector<pb_linear_combination_array<FieldT>> round_a;
    std::vector<pb_linear_combination_array<FieldT>> round_b;
    std::vector<pb_linear_combination_array<FieldT>> round_c;
    std::vector<pb_linear_combination_array<FieldT>> round_d;
    std::vector<pb_linear_combination_array<FieldT>> round_e;
    std::vector<pb_linear_combination_array<FieldT>> round_f;
    std::vector<pb_linear_combination_array<FieldT>> round_g;
    std::vector<pb_linear_combination_array<FieldT>> round_h;
 
    pb_variable_array<FieldT> packed_W;
    std::shared_ptr<sha256_message_schedule_gadget<FieldT>> message_schedule;
    std::vector<sha256_round_function_gadget<FieldT>> round_functions;
 
    pb_variable_array<FieldT> unreduced_output;
    pb_variable_array<FieldT> reduced_output;
    std::vector<lastbits_gadget<FieldT>> reduce_output;
 
public:
    pb_linear_combination_array<FieldT> prev_output;
    pb_variable_array<FieldT> new_block;
    digest_variable<FieldT> output;
 
    sha256_compression_function_gadget(
        protoboard<FieldT> &pb,
        const pb_linear_combination_array<FieldT> &prev_output,
        const pb_variable_array<FieldT> &new_block,
        const digest_variable<FieldT> &output,
        const std::string &annotation_prefix);
    void generate_r1cs_constraints();
    void generate_r1cs_witness();
};
 
template<typename FieldT>
class sha256_two_to_one_hash_gadget : public gadget<FieldT>
{
public:
    typedef libff::bit_vector hash_value_type;
    typedef merkle_authentication_path merkle_authentication_path_type;
 
    std::shared_ptr<sha256_compression_function_gadget<FieldT>> f;
 
    sha256_two_to_one_hash_gadget(
        protoboard<FieldT> &pb,
        const digest_variable<FieldT> &left,
        const digest_variable<FieldT> &right,
        const digest_variable<FieldT> &output,
        const std::string &annotation_prefix);
    sha256_two_to_one_hash_gadget(
        protoboard<FieldT> &pb,
        const size_t block_length,
        const block_variable<FieldT> &input_block,
        const digest_variable<FieldT> &output,
        const std::string &annotation_prefix);
 
    void generate_r1cs_constraints(
        const bool ensure_output_bitness = true); // TODO: ignored for now
    void generate_r1cs_witness();
 
    static size_t get_block_len();
    static size_t get_digest_len();
    static libff::bit_vector get_hash(const libff::bit_vector &input);
 
    static size_t expected_constraints(
        const bool ensure_output_bitness = true); // TODO: ignored for now
};
 
} // namespace libsnark
 
#include <libsnark/gadgetlib1/gadgets/hashes/sha256/sha256_gadget.tcc>
 
#endif // SHA256_GADGET_HPP_