From bcc7aad8264bcff46491d5be5fab4d813e4a0159 Mon Sep 17 00:00:00 2001
From: PlexSheep <software@cscherr.de>
Date: Tue, 2 May 2023 14:05:36 +0200
Subject: [PATCH] iterated squaring start

---
 Cargo.lock               | 31 ++++++++++++++++++++++
 Cargo.toml               |  6 +++++
 src/iterated_squaring.rs | 56 ++++++++++++++++++++++++++++++++++++++++
 src/lib.rs               |  1 +
 src/main.rs              | 17 ++++++++++++
 5 files changed, 111 insertions(+)
 create mode 100644 src/iterated_squaring.rs
 create mode 100644 src/main.rs

diff --git a/Cargo.lock b/Cargo.lock
index 6ba8544..3665f5a 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -51,6 +51,36 @@ dependencies = [
  "autocfg",
 ]
 
+[[package]]
+name = "num-bigint"
+version = "0.4.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f93ab6289c7b344a8a9f60f88d80aa20032336fe78da341afc91c8a2341fc75f"
+dependencies = [
+ "autocfg",
+ "num-integer",
+ "num-traits",
+]
+
+[[package]]
+name = "num-integer"
+version = "0.1.45"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "225d3389fb3509a24c93f5c29eb6bde2586b98d9f016636dff58d7c6f7569cd9"
+dependencies = [
+ "autocfg",
+ "num-traits",
+]
+
+[[package]]
+name = "num-traits"
+version = "0.2.15"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "578ede34cf02f8924ab9447f50c28075b4d3e5b269972345e7e0372b38c6cdcd"
+dependencies = [
+ "autocfg",
+]
+
 [[package]]
 name = "once_cell"
 version = "1.17.1"
@@ -84,6 +114,7 @@ dependencies = [
 name = "plexcryptool"
 version = "0.1.0"
 dependencies = [
+ "num-bigint",
  "pyo3",
 ]
 
diff --git a/Cargo.toml b/Cargo.toml
index 5609980..ed9457c 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -7,6 +7,12 @@ edition = "2021"
 [lib]
 name = "plexcryptool"
 crate-type = ["cdylib"]
+path = "src/lib.rs"
+
+[[bin]]
+name = "plexcryptool"
+path = "src/main.rs"
 
 [dependencies]
+num-bigint = "0.4.3"
 pyo3 = "0.18.1"
diff --git a/src/iterated_squaring.rs b/src/iterated_squaring.rs
new file mode 100644
index 0000000..a96e1aa
--- /dev/null
+++ b/src/iterated_squaring.rs
@@ -0,0 +1,56 @@
+use std::{str::FromStr, array};
+
+use num_bigint::{BigInt, BigUint}; 
+
+/// works, but is forbidden for class
+pub fn calc_exp_in_field_lib(
+    base: BigInt,
+    exp: BigInt, 
+    field: BigInt) -> BigInt {
+    base.modpow(&exp, &field)
+}
+
+/**
+ *  Umwandlung des Exponenten k in die zugehörige Binärdarstellung.
+ *  Ersetzen jeder 0 durch Q und jeder 1 durch QM.
+ *  Nun wird Q als Anweisung zum Quadrieren und M als Anweisung zum Multiplizieren aufgefasst.
+ *  Somit bildet die resultierende Zeichenkette von links nach rechts gelesen eine Vorschrift zur Berechnung von x k . 
+ *  Man beginne mit 1, quadriere für jedes gelesene Q das bisherige Zwischenergebnis und 
+ *  multipliziere es für jedes gelesene M mit x .
+ */
+pub fn calc_exp_in_field(
+    base: BigInt,
+    exp: BigInt, 
+    field: BigInt) -> BigInt {
+    let binary_repr = exp.to_bytes_be();
+    dump_bin(&binary_repr.1);
+
+
+    let instructions: Vec<bool> = bytes_to_bools(&binary_repr.1);
+    dbg!(instructions);
+
+    return base;
+}
+
+fn bytes_to_bools(bytes: &Vec<u8>) -> Vec<bool> {
+    let mut result: Vec<bool> = Vec::new();
+    for byte in bytes {
+        for c in format!("{:b}", byte).chars() {
+            result.push(c == '1');
+        }
+    }
+    result
+}
+
+fn dump_bin(bytes: &Vec<u8>) {
+    let mut total: Vec<u8> = Vec::new();
+    for byte in bytes.iter() {
+        println!("{:#08b}\t| {:#02x}", byte, byte);
+    }
+    print!("0b");
+    for byte in bytes.iter() {
+        print!("{:08b}", byte);
+    }
+    println!();
+
+}
diff --git a/src/lib.rs b/src/lib.rs
index 29c21e3..f6e0153 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,6 +1,7 @@
 use pyo3::prelude::*;
 
 mod binary;
+mod iterated_squaring;
 
 #[pymodule]
 fn register_binary_module(py: Python, parent_module: &PyModule) -> PyResult<()> {
diff --git a/src/main.rs b/src/main.rs
new file mode 100644
index 0000000..6cd05e3
--- /dev/null
+++ b/src/main.rs
@@ -0,0 +1,17 @@
+mod binary;
+mod iterated_squaring;
+
+use std::str::FromStr;
+
+use iterated_squaring::calc_exp_in_field;
+
+use num_bigint;
+
+pub fn main() {
+    let b = num_bigint::BigInt::from_str("17").expect("a");
+    let e = num_bigint::BigInt::from_str("1011201391039").expect("a");
+    let f = num_bigint::BigInt::from_str("101").expect("a");
+    let r = calc_exp_in_field(b.clone(), e, f);
+    assert_eq!(r, b);
+    print!("res is {}\n", r)
+}