src/tasks/mod.rs

@@ -9,7 +9,8 @@ use tasks01::{
     gfmul::gfmul_task,
     pad_oracle::padding_oracle,
     pfmath::{
-        gfdiv, gfpoly_add, gfpoly_divmod, gfpoly_mul, gfpoly_pow, gfpoly_powmod, gfpoly_sort,
+        gfdiv, gfpoly_add, gfpoly_divmod, gfpoly_make_monic, gfpoly_mul, gfpoly_pow, gfpoly_powmod,
+        gfpoly_sort, gfpoly_sqrt,
     },
     poly2block::poly2block,
     sea128::sea128,
@@ -132,6 +133,18 @@ pub fn task_deploy(testcase: &Testcase) -> Result<Value> {
 
             Ok(json)
         }
+        "gfpoly_make_monic" => {
+            let result = gfpoly_make_monic(args)?;
+            let json = json!({"S" : result.to_c_array()});
+
+            Ok(json)
+        }
+        "gfpoly_sqrt" => {
+            let result = gfpoly_sqrt(args)?;
+            let json = json!({"S" : result.to_c_array()});
+
+            Ok(json)
+        }
 
         _ => Err(anyhow!(
             "Fatal. No compatible action found. Json data was {:?}. Arguments were; {:?}",

src/tasks/tasks01/pfmath.rs

@@ -81,6 +81,22 @@ pub fn gfpoly_sort(args: &Value) -> Result<Vec<Polynomial>> {
     Ok(polys)
 }
 
+pub fn gfpoly_make_monic(args: &Value) -> Result<Polynomial> {
+    let mut poly_a = Polynomial::from_c_array(&args["A"].clone());
+
+    poly_a.monic();
+
+    Ok(poly_a)
+}
+
+pub fn gfpoly_sqrt(args: &Value) -> Result<Polynomial> {
+    let poly_a = Polynomial::from_c_array(&args["Q"].clone());
+
+    let result = poly_a.sqrt();
+
+    Ok(result)
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;

src/utils/field.rs

@@ -36,20 +36,45 @@ impl FieldElement {
         BASE64_STANDARD.encode(&self.field_element)
     }
 
-    pub fn pow(&self, mut exponent: u128) -> FieldElement {
+    pub fn pow(mut self, mut exponent: u128) -> FieldElement {
+        let mut result: FieldElement =
+            FieldElement::new(polynomial_2_block(vec![0], "gcm").unwrap());
+
+        if exponent == 1 {
+            eprintln!("special case 1: {:02X?}", self.clone());
+
+            return self;
+        }
+
         if exponent == 0 {
-            // Return polynomial with coefficient 1
-            return FieldElement::new(vec![1]);
+            let result = FieldElement::new(polynomial_2_block(vec![0], "gcm").unwrap());
+
+            eprintln!("Returned value is: {:02X?}", result);
+            return result;
         }
 
-        let base = self.clone();
-        let mut result = base.clone();
-        exponent -= 1; // Subtract 1 because we already set result to base
-
+        //eprintln!("Initial result: {:?}", result);
         while exponent > 0 {
-            result = result * base.clone();
-            exponent -= 1;
+            //eprintln!("Current exponent: {:02X}", exponent);
+            if exponent & 1 == 1 {
+                let temp = &self * &result;
+                //eprintln!("Mult");
+                //eprintln!("After mod: {:?}", temp);
+
+                result = temp
             }
+            let temp_square = &self * &self;
+            // eprintln!("Square");
+
+            // eprintln!("After squaring: {:?}", temp_square);
+            self = temp_square;
+            //eprintln!("After mod: {:?}", self);
+            exponent >>= 1;
+        }
+
+        // eprintln!("result in powmod before reduction: {:02X?}", result);
+
+        // eprintln!("result in powmod after reduction: {:02X?}", result);
 
         result
     }

src/utils/poly.rs

@@ -56,19 +56,63 @@ impl Polynomial {
         output
     }
 
-    pub fn pow(&self, mut exponent: u128) -> Polynomial {
-        if exponent == 0 {
-            return Polynomial::new(vec![FieldElement::new(
+    pub fn pow(mut self, mut exponent: u128) -> Polynomial {
+        let mut result: Polynomial = Polynomial::new(vec![FieldElement::new(
             polynomial_2_block(vec![0], "gcm").unwrap(),
         )]);
+
+        if exponent == 1 {
+            eprintln!("special case 1: {:02X?}", self.clone());
+
+            return self;
         }
 
-        let base = self.clone();
-        let mut result = base.clone();
-        exponent -= 1;
+        if exponent == 0 {
+            let result = Polynomial::new(vec![FieldElement::new(
+                polynomial_2_block(vec![0], "gcm").unwrap(),
+            )]);
+
+            eprintln!("Returned value is: {:02X?}", result);
+            return result;
+        }
+
+        //eprintln!("Initial result: {:?}", result);
         while exponent > 0 {
-            result = result * base.clone();
-            exponent -= 1;
+            //eprintln!("Current exponent: {:02X}", exponent);
+            if exponent & 1 == 1 {
+                let temp = &self * &result;
+                //eprintln!("Mult");
+                //eprintln!("After mod: {:?}", temp);
+
+                result = temp
+            }
+            let temp_square = &self * &self;
+            //eprintln!("Square");
+
+            //eprintln!("After squaring: {:?}", temp_square);
+            self = temp_square;
+            //eprintln!("After mod: {:?}", self);
+            exponent >>= 1;
+        }
+
+        //eprintln!("result in powmod before reduction: {:02X?}", result);
+
+        while !result.polynomial.is_empty()
+            && result
+                .polynomial
+                .last()
+                .unwrap()
+                .as_ref()
+                .iter()
+                .all(|&x| x == 0)
+        {
+            result.polynomial.pop();
+        }
+
+        //eprintln!("result in powmod after reduction: {:02X?}", result);
+
+        if result.is_empty() {
+            result = Polynomial::new(vec![FieldElement::new(vec![0; 16])]);
         }
 
         result
@@ -212,7 +256,7 @@ impl Polynomial {
         true
     }
 
-    fn monic(mut self) -> Self {
+    pub fn monic(&mut self) {
         let divident = self.polynomial.last().unwrap().clone();
 
         for fieldelement in &mut self.polynomial.iter_mut() {
@@ -230,12 +274,18 @@ impl Polynomial {
         {
             self.polynomial.pop();
         }
-
-        if self.is_empty() {
-            self = Polynomial::new(vec![FieldElement::new(vec![0; 16])]);
     }
 
-        self
+    pub fn sqrt(self) -> Self {
+        let mut result = vec![];
+
+        for (position, element) in self.polynomial.iter().enumerate() {
+            if position % 2 == 0 {
+                result.push(element.clone().pow(2u128.pow(127)));
+            }
+        }
+
+        Polynomial::new(result)
     }
 }
 
@@ -1079,22 +1129,22 @@ mod tests {
             "1Ial5rAJGOucIdUe3zh5bw==",
             "gAAAAAAAAAAAAAAAAAAAAA=="
         ]);
-        let element1: Polynomial = Polynomial::from_c_array(&json1);
+        let mut element1: Polynomial = Polynomial::from_c_array(&json1);
 
-        let result = element1.monic();
+        element1.monic();
 
-        assert_eq!(json!(result.to_c_array()), expected);
+        assert_eq!(json!(element1.to_c_array()), expected);
     }
 
     #[test]
     fn test_poly_monic_poly_zero() {
         let json1 = json!(["AAAAAAAAAAAAAAAAAAAAAA=="]);
         let expected = json!(["AAAAAAAAAAAAAAAAAAAAAA=="]);
-        let element1: Polynomial = Polynomial::from_c_array(&json1);
+        let mut element1: Polynomial = Polynomial::from_c_array(&json1);
 
-        let result = element1.monic();
+        element1.monic();
 
-        assert_eq!(json!(result.to_c_array()), expected);
+        assert_eq!(json!(element1.to_c_array()), expected);
     }
 
     #[test]
@@ -1106,9 +1156,34 @@ mod tests {
             "AAAAAAAAAAAAAAAAAAAAAA=="
         ]);
         let expected = json!(["AAAAAAAAAAAAAAAAAAAAAA=="]);
-        let element1: Polynomial = Polynomial::from_c_array(&json1);
+        let mut element1: Polynomial = Polynomial::from_c_array(&json1);
 
-        let result = element1.monic();
+        element1.monic();
+
+        assert_eq!(json!(element1.to_c_array()), expected);
+    }
+
+    #[test]
+    fn test_poly_poly_sqrt() {
+        let json1 = json!([
+            "5TxUxLHO1lHE/rSFquKIAg==",
+            "AAAAAAAAAAAAAAAAAAAAAA==",
+            "0DEUJYdHlmd4X7nzzIdcCA==",
+            "AAAAAAAAAAAAAAAAAAAAAA==",
+            "PKUa1+JHTxHE8y3LbuKIIA==",
+            "AAAAAAAAAAAAAAAAAAAAAA==",
+            "Ds96KiAKKoigKoiKiiKAiA=="
+        ]);
+        let expected = json!([
+            "NeverGonnaGiveYouUpAAA==",
+            "NeverGonnaLetYouDownAA==",
+            "NeverGonnaRunAroundAAA==",
+            "AndDesertYouAAAAAAAAAA=="
+        ]);
+        let element1: Polynomial = Polynomial::from_c_array(&json1);
+        eprintln!("Starting poly sqrt");
+
+        let result = element1.sqrt();
 
         assert_eq!(json!(result.to_c_array()), expected);
     }