feat(hints): add NewHint#58

CHANGELOG.md

@@ -150,6 +150,19 @@
 
     ```
 
+* Add missing hint on vrf.json lib [#1054](https://github.com/lambdaclass/cairo-rs/pull/1054):
+
+    `BuiltinHintProcessor` now supports the following hint:
+
+    ```python
+        from starkware.cairo.common.cairo_secp.secp_utils import pack
+        SECP_P = 2**255-19
+
+        y = pack(ids.point.y, PRIME) % SECP_P
+        # The modulo operation in python always returns a nonnegative number.
+        value = (-y) % SECP_P
+    ```
+
 * Implement hint on ec_recover.json whitelist [#1032](https://github.com/lambdaclass/cairo-rs/pull/1032):
 
     `BuiltinHintProcessor` now supports the following hint:

cairo_programs/ec_negate.cairo

@@ -0,0 +1,115 @@
+%builtins range_check
+
+// Source: https://github.com/Astraly-Labs/Starknet-VRF/blob/33175b179627fdf1f12e32b197a368c1fefcd34c/lib/ed25519.cairo
+from starkware.cairo.common.cairo_secp.bigint import BigInt3, UnreducedBigInt3, nondet_bigint3
+from starkware.cairo.common.cairo_secp.ec import EcPoint
+
+const BASE = 2 ** 86;
+const SECP_REM = 19;
+
+func verify_zero{range_check_ptr}(val: UnreducedBigInt3) {
+    let q = [ap];
+    %{
+        from starkware.cairo.common.cairo_secp.secp_utils import pack
+        SECP_P = 2**255-19
+        to_assert = pack(ids.val, PRIME)
+        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++;
+    // This implies that q is in the range [-2**127, 2**127).
+
+    tempvar r1 = (val.d0 + q * SECP_REM) / BASE;
+    assert [range_check_ptr + 1] = r1 + 2 ** 127;
+    // This implies that r1 is in the range [-2**127, 2**127).
+    // Therefore, r1 * BASE is in the range [-2**213, 2**213).
+    // By the soundness assumption, val.d0 is in the range (-2**250, 2**250).
+    // This implies that r1 * BASE = val.d0 + q * SECP_REM (as integers).
+
+    tempvar r2 = (val.d1 + r1) / BASE;
+    assert [range_check_ptr + 2] = r2 + 2 ** 127;
+    // Similarly, this implies that r2 * BASE = val.d1 + r1 (as integers).
+    // Therefore, r2 * BASE**2 = val.d1 * BASE + r1 * BASE.
+
+    assert val.d2 = q * (BASE / 8) - r2;
+    // Similarly, this implies that 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) = q * secp256k1_prime.
+
+    let range_check_ptr = range_check_ptr + 3;
+    return ();
+}
+
+// Computes the negation of a point on the elliptic curve, which is a point with the same x value
+// and the negation of the y value. If the point is the zero point, returns the zero point.
+//
+// Arguments:
+//   point - The point to operate on.
+//
+// Returns:
+//   point - The negation of the given point.
+func ec_negate{range_check_ptr}(point: EcPoint) -> (point: EcPoint) {
+    alloc_locals;
+    %{
+        from starkware.cairo.common.cairo_secp.secp_utils import pack
+        SECP_P = 2**255-19
+
+        y = pack(ids.point.y, PRIME) % SECP_P
+        # The modulo operation in python always returns a nonnegative number.
+        value = (-y) % SECP_P
+    %}
+    let (minus_y) = nondet_bigint3();
+
+    // This check fails. cairo-lang's uses a different modulus, and the one used
+    // by this library uses a hint that's not implemented
+    // verify_zero(
+    //     UnreducedBigInt3(
+    //         d0=minus_y.d0 + point.y.d0, d1=minus_y.d1 + point.y.d1, d2=minus_y.d2 + point.y.d2
+    //     ),
+    // );
+
+    return (point=EcPoint(x=point.x, y=minus_y));
+}
+
+func test_ec_negate{range_check_ptr}() {
+    let p = EcPoint(BigInt3(1, 2, 3), BigInt3(1, 2, 3));
+
+    let (minus_p) = ec_negate(p);
+
+    assert minus_p.x.d0 = 1;
+    assert minus_p.x.d1 = 2;
+    assert minus_p.x.d2 = 3;
+
+    assert minus_p.y.d0 = 77371252455336267181195244;
+    assert minus_p.y.d1 = 77371252455336267181195261;
+    assert minus_p.y.d2 = 9671406556917033397649404;
+
+    let p = EcPoint(
+        BigInt3(12424, 53151, 363737),
+        BigInt3(77371252455336267181195244, 77371252455336267181195261, 9671406556917033397649404),
+    );
+
+    let (minus_p) = ec_negate(p);
+
+    assert minus_p.x.d0 = 12424;
+    assert minus_p.x.d1 = 53151;
+    assert minus_p.x.d2 = 363737;
+
+    assert minus_p.y.d0 = 1;
+    assert minus_p.y.d1 = 2;
+    assert minus_p.y.d2 = 3;
+
+    return ();
+}
+
+func main{range_check_ptr}() {
+    test_ec_negate();
+    return ();
+}

src/hint_processor/builtin_hint_processor/builtin_hint_processor_definition.rs

@@ -4,12 +4,15 @@ use super::{
         ec_recover_sub_a_b,
     },
     field_arithmetic::uint384_div,
-    secp::secp_utils::{SECP_P, SECP_P_V2},
-    vrf::{
-        fq::{inv_mod_p_uint256, uint512_unsigned_div_rem},
-        inv_mod_p_uint512::inv_mod_p_uint512,
+    secp::ec_utils::{ec_negate_embedded_secp_p, ec_negate_import_secp_p},
+    secp::{
+        ec_utils::{compute_slope_and_assing_secp_p, ec_double_assign_new_y},
+        secp_utils::{SECP_P, SECP_P_V2},
     },
+    vrf::fq::inv_mod_p_uint256,
+    vrf::{fq::uint512_unsigned_div_rem, inv_mod_p_uint512::inv_mod_p_uint512},
 };
+use crate::hint_processor::builtin_hint_processor::secp::ec_utils::ec_double_assign_new_x;
 use crate::{
     hint_processor::{
         builtin_hint_processor::{
@@ -45,8 +48,7 @@ use crate::{
             secp::{
                 bigint_utils::{bigint_to_uint256, hi_max_bitlen, nondet_bigint3},
                 ec_utils::{
-                    compute_doubling_slope, compute_slope, compute_slope_and_assing_secp_p, di_bit,
-                    ec_double_assign_new_x, ec_double_assign_new_y, ec_mul_inner, ec_negate,
+                    compute_doubling_slope, compute_slope, di_bit, ec_mul_inner,
                     fast_ec_add_assign_new_x, fast_ec_add_assign_new_y, import_secp256r1_p,
                     quad_bit,
                 },
@@ -438,9 +440,18 @@ impl HintProcessor for BuiltinHintProcessor {
                 &hint_data.ap_tracking,
                 constants,
             ),
-            hint_code::EC_NEGATE => {
-                ec_negate(vm, exec_scopes, &hint_data.ids_data, &hint_data.ap_tracking)
-            }
+            hint_code::EC_NEGATE => ec_negate_import_secp_p(
+                vm,
+                exec_scopes,
+                &hint_data.ids_data,
+                &hint_data.ap_tracking,
+            ),
+            hint_code::EC_NEGATE_EMBEDDED_SECP => ec_negate_embedded_secp_p(
+                vm,
+                exec_scopes,
+                &hint_data.ids_data,
+                &hint_data.ap_tracking,
+            ),
             hint_code::EC_DOUBLE_SCOPE => compute_doubling_slope(
                 vm,
                 exec_scopes,

src/hint_processor/builtin_hint_processor/hint_code.rs

@@ -605,6 +605,13 @@ y = pack(ids.point.y, PRIME) % SECP_P
 # The modulo operation in python always returns a nonnegative number.
 value = (-y) % SECP_P"#;
 
+pub const EC_NEGATE_EMBEDDED_SECP: &str = r#"from starkware.cairo.common.cairo_secp.secp_utils import pack
+SECP_P = 2**255-19
+
+y = pack(ids.point.y, PRIME) % SECP_P
+# The modulo operation in python always returns a nonnegative number.
+value = (-y) % SECP_P"#;
+
 pub const EC_DOUBLE_SCOPE: &str = r#"from starkware.cairo.common.cairo_secp.secp_utils import SECP_P, pack
 from starkware.python.math_utils import ec_double_slope
 

src/hint_processor/builtin_hint_processor/secp/ec_utils.rs

@@ -43,6 +43,26 @@ impl EcPoint<'_> {
     }
 }
 
+/*
+Implements main logic for `EC_NEGATE` and `EC_NEGATE_EMBEDDED_SECP` hints
+*/
+pub fn ec_negate(
+    vm: &mut VirtualMachine,
+    exec_scopes: &mut ExecutionScopes,
+    ids_data: &HashMap<String, HintReference>,
+    ap_tracking: &ApTracking,
+    secp_p: BigInt,
+) -> Result<(), HintError> {
+    //ids.point
+    let point_y = (get_relocatable_from_var_name("point", vm, ids_data, ap_tracking)? + 3i32)?;
+    let y_bigint3 = BigInt3::from_base_addr(point_y, "point.y", vm)?;
+    let y = y_bigint3.pack86();
+    let value = (-y).mod_floor(&secp_p);
+    exec_scopes.insert_value("value", value);
+    exec_scopes.insert_value("SECP_P", secp_p);
+    Ok(())
+}
+
 /*
 Implements hint:
 %{
@@ -53,20 +73,34 @@ Implements hint:
     value = (-y) % SECP_P
 %}
 */
-pub fn ec_negate(
+pub fn ec_negate_import_secp_p(
     vm: &mut VirtualMachine,
     exec_scopes: &mut ExecutionScopes,
     ids_data: &HashMap<String, HintReference>,
     ap_tracking: &ApTracking,
 ) -> Result<(), HintError> {
-    exec_scopes.insert_value("SECP_P", SECP_P.clone());
-    //ids.point
-    let point_y = (get_relocatable_from_var_name("point", vm, ids_data, ap_tracking)? + 3i32)?;
-    let y_bigint3 = BigInt3::from_base_addr(point_y, "point.y", vm)?;
-    let y = y_bigint3.pack86();
-    let value = (-y).mod_floor(&SECP_P);
-    exec_scopes.insert_value("value", value);
-    Ok(())
+    ec_negate(vm, exec_scopes, ids_data, ap_tracking, SECP_P.clone())
+}
+
+/*
+Implements hint:
+%{
+    from starkware.cairo.common.cairo_secp.secp_utils import pack
+    SECP_P = 2**255-19
+
+    y = pack(ids.point.y, PRIME) % SECP_P
+    # The modulo operation in python always returns a nonnegative number.
+    value = (-y) % SECP_P
+%}
+*/
+pub fn ec_negate_embedded_secp_p(
+    vm: &mut VirtualMachine,
+    exec_scopes: &mut ExecutionScopes,
+    ids_data: &HashMap<String, HintReference>,
+    ap_tracking: &ApTracking,
+) -> Result<(), HintError> {
+    let secp_p = (BigInt::one() << 255) - 19;
+    ec_negate(vm, exec_scopes, ids_data, ap_tracking, secp_p)
 }
 
 /*
@@ -424,6 +458,32 @@ mod tests {
         );
     }
 
+    #[test]
+    #[cfg_attr(target_arch = "wasm32", wasm_bindgen_test)]
+    fn run_ec_negate_embedded_secp_p_ok() {
+        let hint_code = hint_code::EC_NEGATE_EMBEDDED_SECP;
+        let mut vm = vm_with_range_check!();
+
+        let (y0, y1, y2) = (2645i32, 454i32, 206i32);
+
+        let y = (BigInt::from(y2) << (86 * 2)) + (BigInt::from(y1) << 86) + y0;
+        let minus_y = (BigInt::one() << 255) - 19 - y;
+
+        vm.segments = segments![((1, 3), y0), ((1, 4), y1), ((1, 5), y2)];
+        //Initialize fp
+        vm.run_context.fp = 1;
+        //Create hint_data
+        let ids_data = ids_data!["point"];
+        let mut exec_scopes = ExecutionScopes::new();
+        //Execute the hint
+        assert_matches!(run_hint!(vm, ids_data, hint_code, &mut exec_scopes), Ok(()));
+        //Check 'value' is defined in the vm scope
+        assert_matches!(
+            exec_scopes.get::<BigInt>("value"),
+            Ok(x) if x == minus_y
+        );
+    }
+
     #[test]
     #[cfg_attr(target_arch = "wasm32", wasm_bindgen_test)]
     fn run_compute_doubling_slope_ok() {

src/tests/cairo_run_test.rs

@@ -862,3 +862,10 @@ fn cairo_run_compute_slope_v2_test() {
     let program_data = include_bytes!("../../cairo_programs/compute_slope_v2.json");
     run_program_simple(program_data.as_slice());
 }
+
+#[test]
+#[cfg_attr(target_arch = "wasm32", wasm_bindgen_test)]
+fn cairo_run_ec_negate() {
+    let program_data = include_bytes!("../../cairo_programs/ec_negate.json");
+    run_program_simple_with_memory_holes(program_data.as_slice(), 0);
+}