有限体実装終わり

.vscode/launch.json

@@ -1,45 +0,0 @@
-{
-    // IntelliSense を使用して利用可能な属性を学べます。
-    // 既存の属性の説明をホバーして表示します。
-    // 詳細情報は次を確認してください: https://go.microsoft.com/fwlink/?linkid=830387
-    "version": "0.2.0",
-    "configurations": [
-        {
-            "type": "lldb",
-            "request": "launch",
-            "name": "Debug executable 'encrypt'",
-            "cargo": {
-                "args": [
-                    "build",
-                    "--bin=encrypt",
-                    "--package=encrypt"
-                ],
-                "filter": {
-                    "name": "encrypt",
-                    "kind": "bin"
-                }
-            },
-            "args": [],
-            "cwd": "${workspaceFolder}"
-        },
-        {
-            "type": "lldb",
-            "request": "launch",
-            "name": "Debug unit tests in executable 'encrypt'",
-            "cargo": {
-                "args": [
-                    "test",
-                    "--no-run",
-                    "--bin=encrypt",
-                    "--package=encrypt"
-                ],
-                "filter": {
-                    "name": "encrypt",
-                    "kind": "bin"
-                }
-            },
-            "args": [],
-            "cwd": "${workspaceFolder}"
-        }
-    ]
-}

src/common/finite_field.rs

@@ -1,11 +1,14 @@
-use std::{ops::{Add, Sub, Mul, AddAssign, SubAssign, Div, Rem}, fmt::Debug};
+use std::{ops::{Add, Sub, Mul, AddAssign, SubAssign, Div}, fmt::Debug};
 
+use bigdecimal::{num_bigint::BigInt, Num};
 use primitive_types::U512;
 
+use super::math::mod_inv;
+
 #[derive(PartialEq, Debug, Copy, Clone)]
 pub struct FiniteFieldElement {
     pub value: U512,
-    pub p: U512 
+    pub p: U512
 }
 
 impl FiniteFieldElement {
@@ -15,7 +18,7 @@ impl FiniteFieldElement {
 }
 
 impl FiniteFieldElement {
-    fn pow(self, e: U512) -> Self {
+    pub fn pow(self, e: U512) -> Self {
         let k = e.bits();
         let mut a1 = self;
         let mut a2 = self * self;
@@ -102,8 +105,12 @@ impl Div for FiniteFieldElement {
     type Output = Self;
 
     fn div(self, rhs: Self) -> Self::Output {
-        let rhs = rhs.pow(self.p - U512::from(2));
-        self * rhs
+        let left = BigInt::from_str_radix(&format!("{}", rhs.value), 10).unwrap();
+        let right = BigInt::from_str_radix(&format!("{}", rhs.p), 10).unwrap();
+        let mod_inv = mod_inv(left, right);
+        println!("mod_inv: {:?}", mod_inv);
+        let mod_inv = U512::from_str_radix(&format!("{}", mod_inv), 10).unwrap();
+        self * FiniteFieldElement::new(mod_inv, rhs.p)
     }
 }
 

src/common/math.rs

@@ -0,0 +1,37 @@
+use bigdecimal::{num_bigint::BigInt, Zero, One};
+
+pub fn plus_mod(a: BigInt, m: BigInt) -> BigInt {
+    (a.clone() % m.clone() + m.clone()) % m
+}
+
+pub fn mod_inv(a: BigInt, m: BigInt) -> BigInt {
+    let mut a = a;
+    if a < BigInt::zero() {
+        a = a.modpow(&BigInt::one(), &m);
+    }
+
+    let mut x = BigInt::zero();
+    let mut y = BigInt::one();
+    let mut gcd = m.clone();
+    let mut px = BigInt::one();
+    let mut py = BigInt::zero();
+    let mut pgcd = a;
+
+    while gcd.clone() > BigInt::zero() {
+        let q = pgcd.clone() / gcd.clone();
+
+        let tmp = x.clone();
+        x = px.clone() - q.clone() * tmp.clone();
+        px = tmp.clone();
+
+        let tmp = y.clone();
+        y = py.clone() - q.clone() * tmp.clone();
+        py = tmp.clone();
+
+        let tmp = gcd.clone();
+        gcd = pgcd.clone() - q.clone() * tmp.clone();
+        pgcd = tmp.clone();
+    }
+
+    plus_mod(px, m)
+}

src/common/mod.rs

@@ -1 +1,2 @@
-pub mod finite_field;
+pub mod finite_field;
+pub mod math;

src/elliptic_curve/elliptic_curve.rs

@@ -1,4 +1,4 @@
-use std::ops::{Div, Add, Sub, Mul};
+use std::ops::{Add, Mul};
 
 use primitive_types::U512;
 
@@ -47,7 +47,7 @@ impl Add for EllipticCurvePoint {
                 match rhs {
                     EllipticCurvePoint::Point { x: x2, y: y2, a: a2, b: b2 } => {
                         println!("default plus");
-                        
+
                         let p = x1.p;
                         if a != a2 || b != b2 {
                             panic!("Cannot add different curve point.");

src/elliptic_curve/encryption.rs

@@ -1,5 +1,3 @@
-use std::ops::{Mul, Add, Sub, Div};
-
 use primitive_types::U512;
 
 use crate::common::finite_field::FiniteFieldElement;
@@ -29,9 +27,9 @@ impl Encryption {
         println!("get plain mapping");
         for p in &self.plain_mapping {
             match p {
-                EllipticCurvePoint::Point { x: px, y: py, a, b } => {
+                EllipticCurvePoint::Point { x: px, y: py, a: _, b: _ } => {
                     match point {
-                        EllipticCurvePoint::Point { x: ppx, y, a, b } => {
+                        EllipticCurvePoint::Point { x: ppx, y, a: _, b: _ } => {
                             if *px == ppx && *py == y {
                                 return U512::from(x) + U512::from(1u8);
                             }
@@ -55,8 +53,8 @@ impl Encryption {
 
         println!("calc mapping");
         while x < i64::MAX && !(match tmp {
-            EllipticCurvePoint::Point { x: tx, y: ty, a, b } => match point {
-                EllipticCurvePoint::Point { x: px, y: py, a, b } => tx == px && ty == py,
+            EllipticCurvePoint::Point { x: tx, y: ty, a: _, b: _ } => match point {
+                EllipticCurvePoint::Point { x: px, y: py, a: _, b: _ } => tx == px && ty == py,
                 _ => false
             },
             EllipticCurvePoint::Infinity => match point {

src/main.rs

@@ -1,4 +1,4 @@
-use encrypt::{elliptic_curve::{elliptic_curve::{EllipticCurve, EllipticCurvePoint}, encryption::Encryption}, common::finite_field::FiniteFieldElement};
+use encrypt::{elliptic_curve::{elliptic_curve::EllipticCurve, encryption::Encryption}, common::finite_field::FiniteFieldElement};
 use primitive_types::U512;
 
 fn main() {