1329 - enforce that 0th nullifier is non-zero in private kernel circuit

(inner and ordering)
AztecProtocol · Sep 28, 2023 · a5dcc0e · a5dcc0e
1 parent 89e280a
commit a5dcc0e
Show file tree

Hide file tree

Showing 5 changed files with 15 additions and 2 deletions.
diff --git a/circuits/cpp/src/aztec3/circuits/kernel/private/common.cpp b/circuits/cpp/src/aztec3/circuits/kernel/private/common.cpp
@@ -114,6 +114,13 @@ void common_validate_read_requests(DummyBuilder& builder,
     }
 }
 
+void common_validate_0th_nullifier(DummyBuilder& builder, CombinedAccumulatedData<NT> const& end)
+{
+    builder.do_assert(end.new_nullifiers[0] != 0,
+                      "The 0th nullifier in the accumulated nullifier array is zero",
+                      CircuitErrorCode::PRIVATE_KERNEL__0TH_NULLLIFIER_IS_ZERO);
+}
+
 void common_update_end_values(DummyBuilder& builder,
                               PrivateCallData<NT> const& private_call,
                               KernelCircuitPublicInputs<NT>& public_inputs)

diff --git a/circuits/cpp/src/aztec3/circuits/kernel/private/common.hpp b/circuits/cpp/src/aztec3/circuits/kernel/private/common.hpp
@@ -2,6 +2,7 @@
 
 #include "init.hpp"
 
+#include "aztec3/circuits/abis/combined_accumulated_data.hpp"
 #include "aztec3/circuits/abis/contract_deployment_data.hpp"
 #include "aztec3/circuits/abis/function_data.hpp"
 #include "aztec3/circuits/abis/kernel_circuit_public_inputs.hpp"
@@ -13,6 +14,7 @@
 
 namespace aztec3::circuits::kernel::private_kernel {
 
+using aztec3::circuits::abis::CombinedAccumulatedData;
 using aztec3::circuits::abis::ContractDeploymentData;
 using aztec3::circuits::abis::FunctionData;
 using aztec3::circuits::abis::KernelCircuitPublicInputs;
@@ -32,6 +34,8 @@ void common_validate_read_requests(DummyBuilder& builder,
                                    std::array<ReadRequestMembershipWitness<NT, PRIVATE_DATA_TREE_HEIGHT>,
                                               MAX_READ_REQUESTS_PER_CALL> const& read_request_membership_witnesses);
 
+void common_validate_0th_nullifier(DummyBuilder& builder, CombinedAccumulatedData<NT> const& end);
+
 void common_update_end_values(DummyBuilder& builder,
                               PrivateCallData<NT> const& private_call,
                               KernelCircuitPublicInputs<NT>& public_inputs);

diff --git a/circuits/cpp/src/aztec3/circuits/kernel/private/native_private_kernel_circuit_inner.cpp b/circuits/cpp/src/aztec3/circuits/kernel/private/native_private_kernel_circuit_inner.cpp
@@ -112,7 +112,7 @@ void validate_inputs(DummyCircuitBuilder& builder, PrivateKernelInputsInner<NT>
                       "Cannot execute private kernel circuit with an empty private call stack",
                       CircuitErrorCode::PRIVATE_KERNEL__PRIVATE_CALL_STACK_EMPTY);
 
-    // TODO(https://github.com/AztecProtocol/aztec-packages/issues/1329): validate that 0th nullifier is nonzero
+    common_validate_0th_nullifier(builder, private_inputs.previous_kernel.public_inputs.end);
 }
 
 // NOTE: THIS IS A VERY UNFINISHED WORK IN PROGRESS.

diff --git a/circuits/cpp/src/aztec3/circuits/kernel/private/native_private_kernel_circuit_ordering.cpp b/circuits/cpp/src/aztec3/circuits/kernel/private/native_private_kernel_circuit_ordering.cpp
@@ -161,7 +161,8 @@ KernelCircuitPublicInputsFinal<NT> native_private_kernel_circuit_ordering(
     // Do this before any functions can modify the inputs.
     initialise_end_values(private_inputs.previous_kernel, public_inputs);
 
-    // TODO(https://github.com/AztecProtocol/aztec-packages/issues/1329): validate that 0th nullifier is nonzero
+    common_validate_0th_nullifier(builder, private_inputs.previous_kernel.public_inputs.end);
+
     // TODO(https://github.com/AztecProtocol/aztec-packages/issues/1486): validate that `len(new_nullifiers) ==
     // len(nullified_commitments)`
 

diff --git a/circuits/cpp/src/aztec3/utils/circuit_errors.hpp b/circuits/cpp/src/aztec3/utils/circuit_errors.hpp
@@ -34,6 +34,7 @@ enum CircuitErrorCode : uint16_t {
     PRIVATE_KERNEL__UNRESOLVED_NON_TRANSIENT_READ_REQUEST = 2021,
     PRIVATE_KERNEL__IS_INTERNAL_BUT_NOT_SELF_CALL = 2022,
     PRIVATE_KERNEL__TRANSIENT_NEW_NULLIFIER_NO_MATCH = 2023,
+    PRIVATE_KERNEL__0TH_NULLLIFIER_IS_ZERO = 2024,
 
     // Public kernel related errors
     PUBLIC_KERNEL_CIRCUIT_FAILED = 3000,