feat(hints): add NewHint#25 and NewHint#24 (lambdaclass#994)

* Add NewHint#26 * Update changelog * Change assert_matches for assert + is_ok * Get and insert SECP_P from scope where applicable * Add NewHint#25 * Add NewHint#24 * Update changelog * Appease clippy * Rename hint codes * Get or insert N from scope * Change test contract * Fix test * Fix test (for real this time)
dojoengine · Jun 23, 2023 · 83108ec · 83108ec
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diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -31,6 +31,22 @@
     * Added dynamic layout [#879](https://github.com/lambdaclass/cairo-rs/pull/879)
     * `get_segment_size` was exposed [#934](https://github.com/lambdaclass/cairo-rs/pull/934)
 
+* Add missing hints on cairo_secp lib [#994](https://github.com/lambdaclass/cairo-rs/pull/994)::
+
+    `BuiltinHintProcessor` now supports the following hints:
+    ```python
+        from starkware.cairo.common.cairo_secp.secp_utils import pack
+        from starkware.python.math_utils import div_mod, safe_div
+
+        a = pack(ids.a, PRIME)
+        b = pack(ids.b, PRIME)
+        value = res = div_mod(a, b, N)
+    ```
+
+    ```python
+        value = k_plus_one = safe_div(res * b - a, N) + 1
+    ```
+
 * Add missing hint on cairo_secp lib [#992](https://github.com/lambdaclass/cairo-rs/pull/992):
 
     `BuiltinHintProcessor` now supports the following hint:

diff --git a/cairo_programs/div_mod_n.cairo b/cairo_programs/div_mod_n.cairo
@@ -0,0 +1,129 @@
+%builtins range_check
+
+from starkware.cairo.common.cairo_secp.bigint import BigInt3, nondet_bigint3, BASE, bigint_mul
+from starkware.cairo.common.cairo_secp.constants import BETA, N0, N1, N2
+
+// Source: https://github.com/myBraavos/efficient-secp256r1/blob/73cca4d53730cb8b2dcf34e36c7b8f34b96b3230/src/secp256r1/signature.cairo
+
+// Computes a * b^(-1) modulo the size of the elliptic curve (N).
+//
+// Prover assumptions:
+// * All the limbs of a are in the range (-2 ** 210.99, 2 ** 210.99).
+// * All the limbs of b are in the range (-2 ** 124.99, 2 ** 124.99).
+// * b is in the range [0, 2 ** 256).
+//
+// Soundness assumptions:
+// * The limbs of a are in the range (-2 ** 249, 2 ** 249).
+// * The limbs of b are in the range (-2 ** 159.83, 2 ** 159.83).
+func div_mod_n{range_check_ptr}(a: BigInt3, b: BigInt3) -> (res: BigInt3) {
+    %{
+        from starkware.cairo.common.cairo_secp.secp_utils import N, pack
+        from starkware.python.math_utils import div_mod, safe_div
+
+        a = pack(ids.a, PRIME)
+        b = pack(ids.b, PRIME)
+        value = res = div_mod(a, b, N)
+    %}
+    let (res) = nondet_bigint3();
+
+    %{ value = k_plus_one = safe_div(res * b - a, N) + 1 %}
+    let (k_plus_one) = nondet_bigint3();
+    let k = BigInt3(d0=k_plus_one.d0 - 1, d1=k_plus_one.d1, d2=k_plus_one.d2);
+
+    let (res_b) = bigint_mul(res, b);
+    let n = BigInt3(N0, N1, N2);
+    let (k_n) = bigint_mul(k, n);
+
+    // We should now have res_b = k_n + a. Since the numbers are in unreduced form,
+    // we should handle the carry.
+
+    tempvar carry1 = (res_b.d0 - k_n.d0 - a.d0) / BASE;
+    assert [range_check_ptr + 0] = carry1 + 2 ** 127;
+
+    tempvar carry2 = (res_b.d1 - k_n.d1 - a.d1 + carry1) / BASE;
+    assert [range_check_ptr + 1] = carry2 + 2 ** 127;
+
+    tempvar carry3 = (res_b.d2 - k_n.d2 - a.d2 + carry2) / BASE;
+    assert [range_check_ptr + 2] = carry3 + 2 ** 127;
+
+    tempvar carry4 = (res_b.d3 - k_n.d3 + carry3) / BASE;
+    assert [range_check_ptr + 3] = carry4 + 2 ** 127;
+
+    assert res_b.d4 - k_n.d4 + carry4 = 0;
+
+    let range_check_ptr = range_check_ptr + 4;
+
+    return (res=res);
+}
+
+func div_mod_n_alt{range_check_ptr}(a: BigInt3, b: BigInt3) -> (res: BigInt3) {
+    // just used to import N
+    %{
+        from starkware.cairo.common.cairo_secp.secp_utils import N, pack
+        from starkware.python.math_utils import div_mod, safe_div
+
+        a = pack(ids.a, PRIME)
+        b = pack(ids.b, PRIME)
+        value = res = div_mod(a, b, N)
+    %}
+
+    %{
+        from starkware.cairo.common.cairo_secp.secp_utils import pack
+        from starkware.python.math_utils import div_mod, safe_div
+
+        a = pack(ids.a, PRIME)
+        b = pack(ids.b, PRIME)
+        value = res = div_mod(a, b, N)
+    %}
+    let (res) = nondet_bigint3();
+
+    %{ value = k_plus_one = safe_div(res * b - a, N) + 1 %}
+    let (k_plus_one) = nondet_bigint3();
+    let k = BigInt3(d0=k_plus_one.d0 - 1, d1=k_plus_one.d1, d2=k_plus_one.d2);
+
+    let (res_b) = bigint_mul(res, b);
+    let n = BigInt3(N0, N1, N2);
+    let (k_n) = bigint_mul(k, n);
+
+    tempvar carry1 = (res_b.d0 - k_n.d0 - a.d0) / BASE;
+    assert [range_check_ptr + 0] = carry1 + 2 ** 127;
+
+    tempvar carry2 = (res_b.d1 - k_n.d1 - a.d1 + carry1) / BASE;
+    assert [range_check_ptr + 1] = carry2 + 2 ** 127;
+
+    tempvar carry3 = (res_b.d2 - k_n.d2 - a.d2 + carry2) / BASE;
+    assert [range_check_ptr + 2] = carry3 + 2 ** 127;
+
+    tempvar carry4 = (res_b.d3 - k_n.d3 + carry3) / BASE;
+    assert [range_check_ptr + 3] = carry4 + 2 ** 127;
+
+    assert res_b.d4 - k_n.d4 + carry4 = 0;
+
+    let range_check_ptr = range_check_ptr + 4;
+
+    return (res=res);
+}
+
+func test_div_mod_n{range_check_ptr: felt}() {
+    let a: BigInt3 = BigInt3(100, 99, 98);
+    let b: BigInt3 = BigInt3(10, 9, 8);
+
+    let (res) = div_mod_n(a, b);
+
+    assert res = BigInt3(
+        3413472211745629263979533, 17305268010345238170172332, 11991751872105858217578135
+    );
+
+    // test alternative hint
+    let (res_alt) = div_mod_n_alt(a, b);
+
+    assert res_alt = res;
+
+    return ();
+}
+
+func main{range_check_ptr: felt}() {
+    test_div_mod_n();
+
+    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
@@ -38,8 +38,8 @@ use crate::{
                     verify_zero, verify_zero_with_external_const,
                 },
                 signature::{
-                    div_mod_n_packed_divmod, div_mod_n_safe_div, get_point_from_x,
-                    pack_modn_div_modn,
+                    div_mod_n_packed_divmod, div_mod_n_packed_external_n, div_mod_n_safe_div,
+                    get_point_from_x, pack_modn_div_modn,
                 },
             },
             segments::{relocate_segment, temporary_array},
@@ -350,13 +350,20 @@ impl HintProcessor for BuiltinHintProcessor {
             }
             hint_code::IS_ZERO_NONDET => is_zero_nondet(vm, exec_scopes),
             hint_code::IS_ZERO_ASSIGN_SCOPE_VARS => is_zero_assign_scope_variables(exec_scopes),
-            hint_code::DIV_MOD_N_PACKED_DIVMOD => div_mod_n_packed_divmod(
+            hint_code::DIV_MOD_N_PACKED_DIVMOD_V1 => div_mod_n_packed_divmod(
                 vm,
                 exec_scopes,
                 &hint_data.ids_data,
                 &hint_data.ap_tracking,
             ),
-            hint_code::DIV_MOD_N_SAFE_DIV => div_mod_n_safe_div(exec_scopes, "a", "b"),
+            hint_code::DIV_MOD_N_PACKED_DIVMOD_EXTERNAL_N => div_mod_n_packed_external_n(
+                vm,
+                exec_scopes,
+                &hint_data.ids_data,
+                &hint_data.ap_tracking,
+            ),
+            hint_code::DIV_MOD_N_SAFE_DIV => div_mod_n_safe_div(exec_scopes, "a", "b", 0),
+            hint_code::DIV_MOD_N_SAFE_DIV_PLUS_ONE => div_mod_n_safe_div(exec_scopes, "a", "b", 1),
             hint_code::GET_POINT_FROM_X => get_point_from_x(
                 vm,
                 exec_scopes,
@@ -493,7 +500,7 @@ impl HintProcessor for BuiltinHintProcessor {
             hint_code::PACK_MODN_DIV_MODN => {
                 pack_modn_div_modn(vm, exec_scopes, &hint_data.ids_data, &hint_data.ap_tracking)
             }
-            hint_code::XS_SAFE_DIV => div_mod_n_safe_div(exec_scopes, "x", "s"),
+            hint_code::XS_SAFE_DIV => div_mod_n_safe_div(exec_scopes, "x", "s", 0),
             hint_code::UINT384_UNSIGNED_DIV_REM => {
                 uint384_unsigned_div_rem(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
@@ -440,7 +440,14 @@ from starkware.python.math_utils import div_mod
 
 value = x_inv = div_mod(1, x, SECP_P)"#;
 
-pub const DIV_MOD_N_PACKED_DIVMOD: &str = r#"from starkware.cairo.common.cairo_secp.secp_utils import N, pack
+pub const DIV_MOD_N_PACKED_DIVMOD_V1: &str = r#"from starkware.cairo.common.cairo_secp.secp_utils import N, pack
+from starkware.python.math_utils import div_mod, safe_div
+
+a = pack(ids.a, PRIME)
+b = pack(ids.b, PRIME)
+value = res = div_mod(a, b, N)"#;
+
+pub const DIV_MOD_N_PACKED_DIVMOD_EXTERNAL_N: &str = r#"from starkware.cairo.common.cairo_secp.secp_utils import pack
 from starkware.python.math_utils import div_mod, safe_div
 
 a = pack(ids.a, PRIME)
@@ -449,6 +456,9 @@ value = res = div_mod(a, b, N)"#;
 
 pub const DIV_MOD_N_SAFE_DIV: &str = r#"value = k = safe_div(res * b - a, N)"#;
 
+pub const DIV_MOD_N_SAFE_DIV_PLUS_ONE: &str =
+    r#"value = k_plus_one = safe_div(res * b - a, N) + 1"#;
+
 pub const GET_POINT_FROM_X: &str = r#"from starkware.cairo.common.cairo_secp.secp_utils import SECP_P, pack
 
 x_cube_int = pack(ids.x_cube, PRIME) % SECP_P

diff --git a/src/hint_processor/builtin_hint_processor/secp/signature.rs b/src/hint_processor/builtin_hint_processor/secp/signature.rs
@@ -1,7 +1,5 @@
-use crate::any_box;
-use crate::stdlib::{collections::HashMap, ops::Shr, prelude::*};
-
 use crate::{
+    any_box,
     hint_processor::{
         builtin_hint_processor::{
             hint_utils::get_integer_from_var_name,
@@ -11,10 +9,11 @@ use crate::{
     },
     math_utils::{div_mod, safe_div_bigint},
     serde::deserialize_program::ApTracking,
+    stdlib::{collections::HashMap, ops::Shr, prelude::*},
     types::exec_scope::ExecutionScopes,
-    vm::errors::hint_errors::HintError,
-    vm::vm_core::VirtualMachine,
+    vm::{errors::hint_errors::HintError, vm_core::VirtualMachine},
 };
+use core::ops::Add;
 use felt::Felt252;
 use num_bigint::BigInt;
 use num_integer::Integer;
@@ -32,35 +31,57 @@ a = pack(ids.a, PRIME)
 b = pack(ids.b, PRIME)
 value = res = div_mod(a, b, N)
 */
-pub fn div_mod_n_packed_divmod(
+pub fn div_mod_n_packed(
     vm: &mut VirtualMachine,
     exec_scopes: &mut ExecutionScopes,
     ids_data: &HashMap<String, HintReference>,
     ap_tracking: &ApTracking,
+    n: &BigInt,
 ) -> Result<(), HintError> {
     let a = pack(BigInt3::from_var_name("a", vm, ids_data, ap_tracking)?);
     let b = pack(BigInt3::from_var_name("b", vm, ids_data, ap_tracking)?);
 
-    let value = div_mod(&a, &b, &N);
+    let value = div_mod(&a, &b, n);
     exec_scopes.insert_value("a", a);
     exec_scopes.insert_value("b", b);
     exec_scopes.insert_value("value", value.clone());
     exec_scopes.insert_value("res", value);
     Ok(())
 }
 
+pub fn div_mod_n_packed_divmod(
+    vm: &mut VirtualMachine,
+    exec_scopes: &mut ExecutionScopes,
+    ids_data: &HashMap<String, HintReference>,
+    ap_tracking: &ApTracking,
+) -> Result<(), HintError> {
+    exec_scopes.assign_or_update_variable("N", any_box!(N.clone()));
+    div_mod_n_packed(vm, exec_scopes, ids_data, ap_tracking, &N)
+}
+
+pub fn div_mod_n_packed_external_n(
+    vm: &mut VirtualMachine,
+    exec_scopes: &mut ExecutionScopes,
+    ids_data: &HashMap<String, HintReference>,
+    ap_tracking: &ApTracking,
+) -> Result<(), HintError> {
+    let n = exec_scopes.get::<BigInt>("N")?;
+    div_mod_n_packed(vm, exec_scopes, ids_data, ap_tracking, &n)
+}
+
 // Implements hint:
 // value = k = safe_div(res * b - a, N)
 pub fn div_mod_n_safe_div(
     exec_scopes: &mut ExecutionScopes,
     a_alias: &str,
     b_alias: &str,
+    to_add: u64,
 ) -> Result<(), HintError> {
     let a = exec_scopes.get_ref::<BigInt>(a_alias)?;
     let b = exec_scopes.get_ref::<BigInt>(b_alias)?;
     let res = exec_scopes.get_ref::<BigInt>("res")?;
 
-    let value = safe_div_bigint(&(res * b - a), &N)?;
+    let value = safe_div_bigint(&(res * b - a), &N)?.add(to_add);
 
     exec_scopes.insert_value("value", value);
     Ok(())
@@ -163,22 +184,33 @@ mod tests {
     #[test]
     #[cfg_attr(target_arch = "wasm32", wasm_bindgen_test)]
     fn safe_div_ok() {
-        let hint_code = hint_code::DIV_MOD_N_PACKED_DIVMOD;
-        let mut vm = vm!();
+        // "import N"
+        let mut exec_scopes = ExecutionScopes::new();
+        exec_scopes.assign_or_update_variable("N", any_box!(N.clone()));
 
-        vm.segments = segments![
-            ((1, 0), 15),
-            ((1, 1), 3),
-            ((1, 2), 40),
-            ((1, 3), 0),
-            ((1, 4), 10),
-            ((1, 5), 1)
+        let hint_codes = vec![
+            hint_code::DIV_MOD_N_PACKED_DIVMOD_V1,
+            hint_code::DIV_MOD_N_PACKED_DIVMOD_EXTERNAL_N,
         ];
-        vm.run_context.fp = 3;
-        let ids_data = non_continuous_ids_data![("a", -3), ("b", 0)];
-        let mut exec_scopes = ExecutionScopes::new();
-        assert_matches!(run_hint!(vm, ids_data, hint_code, &mut exec_scopes), Ok(()));
-        assert_matches!(div_mod_n_safe_div(&mut exec_scopes, "a", "b"), Ok(()));
+        for hint_code in hint_codes {
+            let mut vm = vm!();
+
+            vm.segments = segments![
+                ((1, 0), 15),
+                ((1, 1), 3),
+                ((1, 2), 40),
+                ((1, 3), 0),
+                ((1, 4), 10),
+                ((1, 5), 1)
+            ];
+            vm.run_context.fp = 3;
+            let ids_data = non_continuous_ids_data![("a", -3), ("b", 0)];
+
+            assert_matches!(run_hint!(vm, ids_data, hint_code, &mut exec_scopes), Ok(()));
+
+            assert_matches!(div_mod_n_safe_div(&mut exec_scopes, "a", "b", 0), Ok(()));
+            assert_matches!(div_mod_n_safe_div(&mut exec_scopes, "a", "b", 1), Ok(()));
+        }
     }
 
     #[test]
@@ -193,7 +225,8 @@ mod tests {
             div_mod_n_safe_div(
                 &mut exec_scopes,
                 "a",
-                "b"
+                "b",
+                0,
             ),
             Err(
                 HintError::Math(MathError::SafeDivFailBigInt(
@@ -290,6 +323,6 @@ mod tests {
         let ids_data = non_continuous_ids_data![("x", -3), ("s", 0)];
         let mut exec_scopes = ExecutionScopes::new();
         assert_matches!(run_hint!(vm, ids_data, hint_code, &mut exec_scopes), Ok(()));
-        assert_matches!(div_mod_n_safe_div(&mut exec_scopes, "x", "s"), Ok(()));
+        assert_matches!(div_mod_n_safe_div(&mut exec_scopes, "x", "s", 0), Ok(()));
     }
 }
diff --git a/src/tests/cairo_run_test.rs b/src/tests/cairo_run_test.rs
@@ -1322,3 +1322,10 @@ fn cairo_run_efficient_secp256r1_ec() {
     let program_data = include_bytes!("../../cairo_programs/efficient_secp256r1_ec.json");
     run_program_simple(program_data.as_slice());
 }
+
+#[test]
+#[cfg_attr(target_arch = "wasm32", wasm_bindgen_test)]
+fn cairo_run_div_mod_n() {
+    let program_data = include_bytes!("../../cairo_programs/div_mod_n.json");
+    run_program_simple(program_data.as_slice());
+}