feat(hints): Implement NewHint#59 (lambdaclass#1053)

* Add hint * Add integration test * Add changelog entry * Typo * Fix invoked hint * Update src/tests/cairo_run_test.rs Co-authored-by: Mario Rugiero <mario.rugiero@lambdaclass.com> * Fix ec_double_assign_new_y * fixes * Fix integration test * Clippy --------- Co-authored-by: Mario Rugiero <mario.rugiero@lambdaclass.com>
dojoengine · Jun 23, 2023 · e256071 · e256071
1 parent 450ca87
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diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -2,14 +2,33 @@
 
 #### Upcoming Changes
 
+Add missing hint on vrf.json lib [#1053](https://github.com/lambdaclass/cairo-rs/pull/1053):
+
+     `BuiltinHintProcessor` now supports the following hint:
+
+     ```python
+    %{
+        from starkware.cairo.common.cairo_secp.secp_utils import SECP_P, pack
+        SECP_P = 2**255-19
+
+        slope = pack(ids.slope, PRIME)
+        x = pack(ids.point.x, PRIME)
+        y = pack(ids.point.y, PRIME)
+
+        value = new_x = (pow(slope, 2, SECP_P) - 2 * x) % SECP_P
+    %}
+    ```
+
 * Implement hint on 0.6.0.json whitelist [#1044](https://github.com/lambdaclass/cairo-rs/pull/1044):
 
      `BuiltinHintProcessor` now supports the following hints:
 
+    ```
     %{
        ids.a_lsb = ids.a & 1
        ids.b_lsb = ids.b & 1
     %}
+    ```
 
 * Implement hint for `starkware.cairo.common.cairo_keccak.keccak._block_permutation` as described by whitelist `starknet/security/whitelists/cairo_keccak.json` [#1046](https://github.com/lambdaclass/cairo-rs/pull/1046)
 

diff --git a/cairo_programs/ec_double_assign_new_x_v3.cairo b/cairo_programs/ec_double_assign_new_x_v3.cairo
@@ -0,0 +1,80 @@
+from starkware.cairo.common.cairo_secp.bigint import BigInt3, nondet_bigint3, UnreducedBigInt3
+from cairo_programs.compute_slope_v2 import verify_zero, unreduced_mul
+from cairo_programs.compute_doubling_slope_v2 import compute_doubling_slope, EcPoint, unreduced_sqr
+
+// Computes the addition of a given point to itself.
+//
+// Arguments:
+//   point - the point to operate on.
+//
+// Returns:
+//   res - a point representing point + point.
+func ec_double{range_check_ptr}(point: EcPoint) -> (res: EcPoint) {
+    // The zero point.
+    if (point.x.d0 == 0) {
+        if (point.x.d1 == 0) {
+            if (point.x.d2 == 0) {
+                return (res=point);
+            }
+        }
+    }
+
+    let (slope: BigInt3) = compute_doubling_slope(point);
+    let (slope_sqr: UnreducedBigInt3) = unreduced_sqr(slope);
+
+    %{
+        from starkware.cairo.common.cairo_secp.secp_utils import pack
+        SECP_P = 2**255-19
+
+        slope = pack(ids.slope, PRIME)
+        x = pack(ids.point.x, PRIME)
+        y = pack(ids.point.y, PRIME)
+
+        value = new_x = (pow(slope, 2, SECP_P) - 2 * x) % SECP_P
+    %}
+
+    let (new_x: BigInt3) = nondet_bigint3();
+
+    %{ value = new_y = (slope * (x - new_x) - y) % SECP_P %}
+    let (new_y: BigInt3) = nondet_bigint3();
+
+    verify_zero(
+        UnreducedBigInt3(
+            d0=slope_sqr.d0 - new_x.d0 - 2 * point.x.d0,
+            d1=slope_sqr.d1 - new_x.d1 - 2 * point.x.d1,
+            d2=slope_sqr.d2 - new_x.d2 - 2 * point.x.d2,
+        ),
+    );
+
+    let (x_diff_slope: UnreducedBigInt3) = unreduced_mul(
+        BigInt3(d0=point.x.d0 - new_x.d0, d1=point.x.d1 - new_x.d1, d2=point.x.d2 - new_x.d2), slope
+    );
+
+    verify_zero(
+        UnreducedBigInt3(
+            d0=x_diff_slope.d0 - point.y.d0 - new_y.d0,
+            d1=x_diff_slope.d1 - point.y.d1 - new_y.d1,
+            d2=x_diff_slope.d2 - point.y.d2 - new_y.d2,
+        ),
+    );
+
+    return (res=EcPoint(new_x, new_y));
+}
+
+func main{range_check_ptr}() {
+    let x = BigInt3(1,2,3);
+    let y = BigInt3(4,5,6);
+    let p = EcPoint(x, y);
+
+    let (r) = ec_double(p);
+
+    assert r.x.d0 = 15463639180909693576579425;
+    assert r.x.d1 = 18412232947780787290771221;
+    assert r.x.d2 = 2302636566907525872042731;
+
+    assert r.y.d0 = 62720835442754730087165024;
+    assert r.y.d1 = 51587896485732116326812460;
+    assert r.y.d2 = 1463255073263285938516131;
+
+    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
@@ -519,8 +519,21 @@ impl HintProcessor for BuiltinHintProcessor {
                 &SECP_P,
             ),
             hint_code::EC_DOUBLE_ASSIGN_NEW_X_V1 | hint_code::EC_DOUBLE_ASSIGN_NEW_X_V2 => {
-                ec_double_assign_new_x(vm, exec_scopes, &hint_data.ids_data, &hint_data.ap_tracking)
+                ec_double_assign_new_x(
+                    vm,
+                    exec_scopes,
+                    &hint_data.ids_data,
+                    &hint_data.ap_tracking,
+                    &SECP_P,
+                )
             }
+            hint_code::EC_DOUBLE_ASSIGN_NEW_X_V3 => ec_double_assign_new_x(
+                vm,
+                exec_scopes,
+                &hint_data.ids_data,
+                &hint_data.ap_tracking,
+                &SECP_P_V2,
+            ),
             hint_code::EC_DOUBLE_ASSIGN_NEW_Y => ec_double_assign_new_y(exec_scopes),
             hint_code::KECCAK_WRITE_ARGS => {
                 keccak_write_args(vm, &hint_data.ids_data, &hint_data.ap_tracking)

diff --git a/src/hint_processor/builtin_hint_processor/hint_code.rs b/src/hint_processor/builtin_hint_processor/hint_code.rs
@@ -696,6 +696,15 @@ y = pack(ids.point.y, PRIME)
 
 value = new_x = (pow(slope, 2, SECP_P) - 2 * x) % SECP_P"#;
 
+pub const EC_DOUBLE_ASSIGN_NEW_X_V3: &str = r#"from starkware.cairo.common.cairo_secp.secp_utils import pack
+SECP_P = 2**255-19
+
+slope = pack(ids.slope, PRIME)
+x = pack(ids.point.x, PRIME)
+y = pack(ids.point.y, PRIME)
+
+value = new_x = (pow(slope, 2, SECP_P) - 2 * x) % SECP_P"#;
+
 pub const EC_DOUBLE_ASSIGN_NEW_Y: &str = r#"value = new_y = (slope * (x - new_x) - y) % SECP_P"#;
 
 pub const SHA256_INPUT: &str = r#"ids.full_word = int(ids.n_bytes >= 4)"#;

diff --git a/src/hint_processor/builtin_hint_processor/secp/ec_utils.rs b/src/hint_processor/builtin_hint_processor/secp/ec_utils.rs
@@ -210,18 +210,19 @@ pub fn ec_double_assign_new_x(
     exec_scopes: &mut ExecutionScopes,
     ids_data: &HashMap<String, HintReference>,
     ap_tracking: &ApTracking,
+    secp_p: &BigInt,
 ) -> Result<(), HintError> {
-    exec_scopes.insert_value("SECP_P", SECP_P.clone());
+    exec_scopes.insert_value("SECP_P", secp_p.clone());
     //ids.slope
     let slope = BigInt3::from_var_name("slope", vm, ids_data, ap_tracking)?;
     //ids.point
     let point = EcPoint::from_var_name("point", vm, ids_data, ap_tracking)?;
 
-    let slope = slope.pack86();
-    let x = point.x.pack86();
-    let y = point.y.pack86();
+    let slope = slope.pack86().mod_floor(secp_p);
+    let x = point.x.pack86().mod_floor(secp_p);
+    let y = point.y.pack86().mod_floor(secp_p);
 
-    let value = (slope.pow(2) - (&x << 1u32)).mod_floor(&SECP_P);
+    let value = (slope.pow(2) - (&x << 1u32)).mod_floor(secp_p);
 
     //Assign variables to vm scope
     exec_scopes.insert_value("slope", slope);
@@ -238,14 +239,15 @@ Implements hint:
 */
 pub fn ec_double_assign_new_y(exec_scopes: &mut ExecutionScopes) -> Result<(), HintError> {
     //Get variables from vm scope
-    let (slope, x, new_x, y) = (
+    let (slope, x, new_x, y, secp_p) = (
         exec_scopes.get::<BigInt>("slope")?,
         exec_scopes.get::<BigInt>("x")?,
         exec_scopes.get::<BigInt>("new_x")?,
         exec_scopes.get::<BigInt>("y")?,
+        exec_scopes.get::<BigInt>("SECP_P")?,
     );
 
-    let value = (slope * (x - new_x) - y).mod_floor(&SECP_P);
+    let value = (slope * (x - new_x) - y).mod_floor(&secp_p);
     exec_scopes.insert_value("value", value.clone());
     exec_scopes.insert_value("new_y", value);
     Ok(())
@@ -855,7 +857,8 @@ mod tests {
             (
                 "y",
                 bigint_str!("4310143708685312414132851373791311001152018708061750480")
-            )
+            ),
+            ("SECP_P", (*SECP_P).clone())
         ];
         //Execute the hint
         assert_matches!(

diff --git a/src/tests/cairo_run_test.rs b/src/tests/cairo_run_test.rs
@@ -883,3 +883,10 @@ fn cairo_run_compute_doubling_slope_v2_test() {
     let program_data = include_bytes!("../../cairo_programs/compute_doubling_slope_v2.json");
     run_program_simple(program_data.as_slice());
 }
+
+#[test]
+#[cfg_attr(target_arch = "wasm32", wasm_bindgen_test)]
+fn ec_double_assign_new_x_v3() {
+    let program_data = include_bytes!("../../cairo_programs/ec_double_assign_new_x_v3.json");
+    run_program_simple(program_data.as_slice());
+}