Add NewHint#26

lambdaclass · Apr 14, 2023 · 610f170 · 610f170
1 parent 741a208
commit 610f170
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Showing 4 changed files with 82 additions and 33 deletions.
diff --git a/cairo_programs/ed25519_field.cairo b/cairo_programs/ed25519_field.cairo
@@ -51,6 +51,51 @@ func verify_zero{range_check_ptr}(val: UnreducedBigInt3) {
     return ();
 }
 
+// Source: https://github.com/myBraavos/efficient-secp256r1/blob/73cca4d53730cb8b2dcf34e36c7b8f34b96b3230/src/secp256r1/ec.cairo#L106
+func verify_zero_alt{range_check_ptr}(val: UnreducedBigInt3) {
+    let x = val;
+    // Used just to import pack in scope
+    %{
+        from starkware.cairo.common.cairo_secp.secp_utils import SECP_P, pack
+
+        value = pack(ids.x, PRIME) % SECP_P
+    %}
+    nondet_bigint3();
+
+    let q = [ap];
+    %{
+        from starkware.cairo.common.cairo_secp.secp_utils import pack
+
+        q, r = divmod(pack(ids.val, PRIME), SECP_P)
+        assert r == 0, f"verify_zero: Invalid input {ids.val.d0, ids.val.d1, ids.val.d2}."
+        ids.q = q % PRIME
+    %}
+    let q_biased = [ap + 1];
+    q_biased = q + 2 ** 127, ap++;
+    [range_check_ptr] = q_biased, ap++;
+
+    tempvar r1 = (val.d0 + q * SECP_REM) / BASE;
+    assert [range_check_ptr + 1] = r1 + 2 ** 127;
+    // This implies r1 * BASE = val.d0 + q * SECP_REM (as integers).
+
+    tempvar r2 = (val.d1 + r1) / BASE;
+    assert [range_check_ptr + 2] = r2 + 2 ** 127;
+    // This implies r2 * BASE = val.d1 + r1 (as integers).
+    // Therefore, r2 * BASE**2 = val.d1 * BASE + r1 * BASE.
+
+    assert val.d2 = q * (BASE / 4) - r2;
+    // This implies q * BASE / 4 = val.d2 + r2 (as integers).
+    // Therefore,
+    //   q * BASE**3 / 4 = val.d2 * BASE**2 + r2 * BASE ** 2 =
+    //   val.d2 * BASE**2 + val.d1 * BASE + r1 * BASE =
+    //   val.d2 * BASE**2 + val.d1 * BASE + val.d0 + q * SECP_REM =
+    //   val + q * SECP_REM.
+    // Hence, val = q * (BASE**3 / 4 - SECP_REM) = q * (2**256 - SECP_REM).
+
+    let range_check_ptr = range_check_ptr + 3;
+    return ();
+}
+
 func test_verify_zero{range_check_ptr: felt}() {
     let val = UnreducedBigInt3(0, 0, 0);
 
@@ -59,8 +104,17 @@ func test_verify_zero{range_check_ptr: felt}() {
     return ();
 }
 
+func test_verify_zero_alt{range_check_ptr: felt}() {
+    let val = UnreducedBigInt3(0, 0, 0);
+
+    verify_zero_alt(val);
+
+    return ();
+}
+
 func main{range_check_ptr: felt}() {
     test_verify_zero();
+    test_verify_zero_alt();
 
     return ();
 }
diff --git a/src/hint_processor/builtin_hint_processor/builtin_hint_processor_definition.rs b/src/hint_processor/builtin_hint_processor/builtin_hint_processor_definition.rs
@@ -244,7 +244,7 @@ impl HintProcessor for BuiltinHintProcessor {
             hint_code::BLAKE2S_COMPUTE => {
                 compute_blake2s(vm, &hint_data.ids_data, &hint_data.ap_tracking)
             }
-            hint_code::VERIFY_ZERO_V1 | hint_code::VERIFY_ZERO_V2 => {
+            hint_code::VERIFY_ZERO_V1 | hint_code::VERIFY_ZERO_V2 | hint_code::VERIFY_ZERO_V3 => {
                 verify_zero(vm, &hint_data.ids_data, &hint_data.ap_tracking)
             }
             hint_code::NONDET_BIGINT3 => {

diff --git a/src/hint_processor/builtin_hint_processor/hint_code.rs b/src/hint_processor/builtin_hint_processor/hint_code.rs
@@ -383,6 +383,12 @@ q, r = divmod(pack(ids.val, PRIME), SECP_P)
 assert r == 0, f"verify_zero: Invalid input {ids.val.d0, ids.val.d1, ids.val.d2}."
 ids.q = q % PRIME"#;
 
+pub(crate) const VERIFY_ZERO_V3: &str = r#"from starkware.cairo.common.cairo_secp.secp_utils import pack
+
+q, r = divmod(pack(ids.val, PRIME), SECP_P)
+assert r == 0, f"verify_zero: Invalid input {ids.val.d0, ids.val.d1, ids.val.d2}."
+ids.q = q % PRIME"#;
+
 pub(crate) const REDUCE: &str = r#"from starkware.cairo.common.cairo_secp.secp_utils import SECP_P, pack
 
 value = pack(ids.x, PRIME) % SECP_P"#;

diff --git a/src/hint_processor/builtin_hint_processor/secp/field_utils.rs b/src/hint_processor/builtin_hint_processor/secp/field_utils.rs
@@ -154,38 +154,27 @@ mod tests {
     #[test]
     #[cfg_attr(target_arch = "wasm32", wasm_bindgen_test)]
     fn run_verify_zero_ok() {
-        let hint_code = "from starkware.cairo.common.cairo_secp.secp_utils import SECP_P, pack\n\nq, r = divmod(pack(ids.val, PRIME), SECP_P)\nassert r == 0, f\"verify_zero: Invalid input {ids.val.d0, ids.val.d1, ids.val.d2}.\"\nids.q = q % PRIME";
-        let mut vm = vm_with_range_check!();
-        //Initialize run_context
-        run_context!(vm, 0, 9, 9);
-        //Create hint data
-        let ids_data = non_continuous_ids_data![("val", -5), ("q", 0)];
-        vm.segments = segments![((1, 4), 0), ((1, 5), 0), ((1, 6), 0)];
-        //Execute the hint
-        assert_matches!(
-            run_hint!(vm, ids_data, hint_code, exec_scopes_ref!()),
-            Ok(())
-        );
-        //Check hint memory inserts
-        //ids.q
-        check_memory![vm.segments.memory, ((1, 9), 0)];
-    }
-
-    #[test]
-    #[cfg_attr(target_arch = "wasm32", wasm_bindgen_test)]
-    fn run_verify_zero_without_pack_ok() {
-        let hint_code = "from starkware.cairo.common.cairo_secp.secp_utils import SECP_P\nq, r = divmod(pack(ids.val, PRIME), SECP_P)\nassert r == 0, f\"verify_zero: Invalid input {ids.val.d0, ids.val.d1, ids.val.d2}.\"\nids.q = q % PRIME";
-        let mut vm = vm_with_range_check!();
-        //Initialize run_context
-        run_context!(vm, 0, 9, 9);
-        //Create hint data
-        let ids_data = non_continuous_ids_data![("val", -5), ("q", 0)];
-        vm.segments = segments![((1, 4), 0), ((1, 5), 0), ((1, 6), 0)];
-        //Execute the hint
-        assert!(run_hint!(vm, ids_data, hint_code, exec_scopes_ref!()).is_ok());
-        //Check hint memory inserts
-        //ids.q
-        check_memory![vm.segments.memory, ((1, 9), 0)];
+        let hint_codes = vec![
+            "from starkware.cairo.common.cairo_secp.secp_utils import SECP_P, pack\n\nq, r = divmod(pack(ids.val, PRIME), SECP_P)\nassert r == 0, f\"verify_zero: Invalid input {ids.val.d0, ids.val.d1, ids.val.d2}.\"\nids.q = q % PRIME",
+            "from starkware.cairo.common.cairo_secp.secp_utils import SECP_P\nq, r = divmod(pack(ids.val, PRIME), SECP_P)\nassert r == 0, f\"verify_zero: Invalid input {ids.val.d0, ids.val.d1, ids.val.d2}.\"\nids.q = q % PRIME",
+            "from starkware.cairo.common.cairo_secp.secp_utils import pack\n\nq, r = divmod(pack(ids.val, PRIME), SECP_P)\nassert r == 0, f\"verify_zero: Invalid input {ids.val.d0, ids.val.d1, ids.val.d2}.\"\nids.q = q % PRIME",
+        ];
+        for hint_code in hint_codes {
+            let mut vm = vm_with_range_check!();
+            //Initialize run_context
+            run_context!(vm, 0, 9, 9);
+            //Create hint data
+            let ids_data = non_continuous_ids_data![("val", -5), ("q", 0)];
+            vm.segments = segments![((1, 4), 0), ((1, 5), 0), ((1, 6), 0)];
+            //Execute the hint
+            assert_matches!(
+                run_hint!(vm, ids_data, hint_code, exec_scopes_ref!()),
+                Ok(())
+            );
+            //Check hint memory inserts
+            //ids.q
+            check_memory![vm.segments.memory, ((1, 9), 0)];
+        }
     }
 
     #[test]