From d63386d7a48cd78243b68e780bc287b94b520d35 Mon Sep 17 00:00:00 2001
From: feltroidprime <feltroidprime@protonmail.com>
Date: Tue, 13 Aug 2024 10:36:30 +0200
Subject: [PATCH] adds projective_to_affine tool

---
 hydra/definitions.py                          |   4 +
 .../examples/snarkjs_vk_bn254.json            | 184 +++++++++---------
 .../parsing_utils.py                          |  16 +-
 3 files changed, 106 insertions(+), 98 deletions(-)

diff --git a/hydra/definitions.py b/hydra/definitions.py
index 90407f29..c1452e22 100644
--- a/hydra/definitions.py
+++ b/hydra/definitions.py
@@ -49,6 +49,10 @@ class CurveID(Enum):
     def from_str(s: str) -> "CurveID":
         return CurveID(CurveID.find_value_in_string(s))
 
+    @property
+    def p(self) -> int:
+        return CURVES[self.value].p
+
     @staticmethod
     def find_value_in_string(s: str) -> int | None:
         """
diff --git a/tools/starknet/groth16_contract_generator/examples/snarkjs_vk_bn254.json b/tools/starknet/groth16_contract_generator/examples/snarkjs_vk_bn254.json
index c690ae2f..24dd8281 100644
--- a/tools/starknet/groth16_contract_generator/examples/snarkjs_vk_bn254.json
+++ b/tools/starknet/groth16_contract_generator/examples/snarkjs_vk_bn254.json
@@ -1,94 +1,94 @@
 {
- "protocol": "groth16",
- "curve": "bn128",
- "nPublic": 1,
- "vk_alpha_1": [
-  "20491192805390485299153009773594534940189261866228447918068658471970481763042",
-  "9383485363053290200918347156157836566562967994039712273449902621266178545958",
-  "1"
- ],
- "vk_beta_2": [
-  [
-   "6375614351688725206403948262868962793625744043794305715222011528459656738731",
-   "4252822878758300859123897981450591353533073413197771768651442665752259397132"
-  ],
-  [
-   "10505242626370262277552901082094356697409835680220590971873171140371331206856",
-   "21847035105528745403288232691147584728191162732299865338377159692350059136679"
-  ],
-  [
-   "1",
-   "0"
-  ]
- ],
- "vk_gamma_2": [
-  [
-   "10857046999023057135944570762232829481370756359578518086990519993285655852781",
-   "11559732032986387107991004021392285783925812861821192530917403151452391805634"
-  ],
-  [
-   "8495653923123431417604973247489272438418190587263600148770280649306958101930",
-   "4082367875863433681332203403145435568316851327593401208105741076214120093531"
-  ],
-  [
-   "1",
-   "0"
-  ]
- ],
- "vk_delta_2": [
-  [
-   "10857046999023057135944570762232829481370756359578518086990519993285655852781",
-   "11559732032986387107991004021392285783925812861821192530917403151452391805634"
-  ],
-  [
-   "8495653923123431417604973247489272438418190587263600148770280649306958101930",
-   "4082367875863433681332203403145435568316851327593401208105741076214120093531"
-  ],
-  [
-   "1",
-   "0"
-  ]
- ],
- "vk_alphabeta_12": [
-  [
-   [
-    "2029413683389138792403550203267699914886160938906632433982220835551125967885",
-    "21072700047562757817161031222997517981543347628379360635925549008442030252106"
-   ],
-   [
-    "5940354580057074848093997050200682056184807770593307860589430076672439820312",
-    "12156638873931618554171829126792193045421052652279363021382169897324752428276"
-   ],
-   [
-    "7898200236362823042373859371574133993780991612861777490112507062703164551277",
-    "7074218545237549455313236346927434013100842096812539264420499035217050630853"
-   ]
-  ],
-  [
-   [
-    "7077479683546002997211712695946002074877511277312570035766170199895071832130",
-    "10093483419865920389913245021038182291233451549023025229112148274109565435465"
-   ],
-   [
-    "4595479056700221319381530156280926371456704509942304414423590385166031118820",
-    "19831328484489333784475432780421641293929726139240675179672856274388269393268"
-   ],
-   [
-    "11934129596455521040620786944827826205713621633706285934057045369193958244500",
-    "8037395052364110730298837004334506829870972346962140206007064471173334027475"
-   ]
-  ]
- ],
- "IC": [
-  [
-   "3230230166848506278169341429844025995277520944155248223069557471517720414099",
-   "13103770257244981396389858672913686503786254567452595604017418062281627967708",
-   "1"
-  ],
-  [
-   "19371697418061315618343891460787183627139127309393053314424436252400705071207",
-   "9445383417235588302514232777371752216736256846043789115945856987874292878586",
-   "1"
-  ]
- ]
+    "protocol": "groth16",
+    "curve": "bn128",
+    "nPublic": 1,
+    "vk_alpha_1": [
+        "20491192805390485299153009773594534940189261866228447918068658471970481763042",
+        "9383485363053290200918347156157836566562967994039712273449902621266178545958",
+        "1"
+    ],
+    "vk_beta_2": [
+        [
+            "6375614351688725206403948262868962793625744043794305715222011528459656738731",
+            "4252822878758300859123897981450591353533073413197771768651442665752259397132"
+        ],
+        [
+            "10505242626370262277552901082094356697409835680220590971873171140371331206856",
+            "21847035105528745403288232691147584728191162732299865338377159692350059136679"
+        ],
+        [
+            "1",
+            "0"
+        ]
+    ],
+    "vk_gamma_2": [
+        [
+            "10857046999023057135944570762232829481370756359578518086990519993285655852781",
+            "11559732032986387107991004021392285783925812861821192530917403151452391805634"
+        ],
+        [
+            "8495653923123431417604973247489272438418190587263600148770280649306958101930",
+            "4082367875863433681332203403145435568316851327593401208105741076214120093531"
+        ],
+        [
+            "1",
+            "0"
+        ]
+    ],
+    "vk_delta_2": [
+        [
+            "10857046999023057135944570762232829481370756359578518086990519993285655852781",
+            "11559732032986387107991004021392285783925812861821192530917403151452391805634"
+        ],
+        [
+            "8495653923123431417604973247489272438418190587263600148770280649306958101930",
+            "4082367875863433681332203403145435568316851327593401208105741076214120093531"
+        ],
+        [
+            "1",
+            "0"
+        ]
+    ],
+    "vk_alphabeta_12": [
+        [
+            [
+                "2029413683389138792403550203267699914886160938906632433982220835551125967885",
+                "21072700047562757817161031222997517981543347628379360635925549008442030252106"
+            ],
+            [
+                "5940354580057074848093997050200682056184807770593307860589430076672439820312",
+                "12156638873931618554171829126792193045421052652279363021382169897324752428276"
+            ],
+            [
+                "7898200236362823042373859371574133993780991612861777490112507062703164551277",
+                "7074218545237549455313236346927434013100842096812539264420499035217050630853"
+            ]
+        ],
+        [
+            [
+                "7077479683546002997211712695946002074877511277312570035766170199895071832130",
+                "10093483419865920389913245021038182291233451549023025229112148274109565435465"
+            ],
+            [
+                "4595479056700221319381530156280926371456704509942304414423590385166031118820",
+                "19831328484489333784475432780421641293929726139240675179672856274388269393268"
+            ],
+            [
+                "11934129596455521040620786944827826205713621633706285934057045369193958244500",
+                "8037395052364110730298837004334506829870972346962140206007064471173334027475"
+            ]
+        ]
+    ],
+    "IC": [
+        [
+            "3230230166848506278169341429844025995277520944155248223069557471517720414099",
+            "13103770257244981396389858672913686503786254567452595604017418062281627967708",
+            "1"
+        ],
+        [
+            "19371697418061315618343891460787183627139127309393053314424436252400705071207",
+            "9445383417235588302514232777371752216736256846043789115945856987874292878586",
+            "1"
+        ]
+    ]
 }
diff --git a/tools/starknet/groth16_contract_generator/parsing_utils.py b/tools/starknet/groth16_contract_generator/parsing_utils.py
index 02cfd911..c0a03fa5 100644
--- a/tools/starknet/groth16_contract_generator/parsing_utils.py
+++ b/tools/starknet/groth16_contract_generator/parsing_utils.py
@@ -44,6 +44,15 @@ def try_parse_g1_point_from_key(
     return try_parse_g1_point(point, curve_id)
 
 
+def proj_to_affine(x, y, z, curve_id: CurveID) -> G1Point:
+    x, y, z = io.to_int(x), io.to_int(y), io.to_int(z)
+    p = curve_id.p
+    z = pow(z, -1, p)
+    x = x * z % p
+    y = y * z % p
+    return G1Point(x=x, y=y, curve_id=curve_id)
+
+
 def try_parse_g1_point(point: Any, curve_id: CurveID = None) -> G1Point:
     if isinstance(point, dict):
         return G1Point(
@@ -59,12 +68,7 @@ def try_parse_g1_point(point: Any, curve_id: CurveID = None) -> G1Point:
                 curve_id=curve_id,
             )
         elif len(point) == 3:
-            assert io.to_int(point[2]) == 1, f"Non standard projective coordinates"
-            return G1Point(
-                x=io.to_int(point[0]),
-                y=io.to_int(point[1]),
-                curve_id=curve_id,
-            )
+            return proj_to_affine(point[0], point[1], point[2], curve_id)
         else:
             raise ValueError(f"Invalid point: {point}")
     else: