Pre set 2 refactors

examples/set1_5/main.rs

@@ -3,7 +3,7 @@ use cryptopals::{prelude::*, bvec};
 fn main() {
     let input = Vec::from_text(
         "Burning 'em, if you ain't quick and nimble
-I go crazy when I hear a cymbal");
+I go crazy when I hear a cymbal").unwrap();
     let output = bvec!("output.txt");
 
     assert_eq!(input.xor_repeating(&b"ICE".to_vec()).unwrap(), output);

examples/set1_7/main.rs

@@ -1,17 +1,13 @@
 #![feature(array_chunks)]
-use aes::{cipher::{KeyInit, generic_array::GenericArray, Key, BlockEncrypt, BlockDecrypt}, Aes128, Block};
-use cryptopals::{prelude::*, bvec, bvec64};
+use cryptopals::{prelude::*, bvec, bvec64, friendly::aes128};
 
 fn main() {
-    let key: Key<Aes128> = GenericArray::from(*b"YELLOW SUBMARINE");
-    let aes = aes::Aes128::new(&key);
+    let key = *b"YELLOW SUBMARINE";
 
     let input = bvec64!("input.txt");
     let mut output = Vec::new();
     for chunk in input.array_chunks::<16>() {
-        let mut block: Block = GenericArray::from(*chunk);
-        aes.decrypt_block(&mut block);
-        output.extend(<[u8; 16]>::from(block));
+        output.extend(aes128::decrypt(key, *chunk));
     }
 
     dbg!(output.to_text().unwrap());

src/friendly.rs

@@ -0,0 +1,21 @@
+pub mod aes128 {
+    use aes::cipher::{generic_array::GenericArray, KeyInit, BlockEncrypt, BlockDecrypt};
+
+    pub fn encrypt(key: [u8; 16], block: [u8; 16]) -> [u8; 16] {
+        let key = GenericArray::from(key);
+        let aes = aes::Aes128::new(&key);
+
+        let mut block = GenericArray::from(block);
+        aes.encrypt_block(&mut block);
+        <[u8; 16]>::from(block)
+    }
+
+    pub fn decrypt(key: [u8; 16], block: [u8; 16]) -> [u8; 16] {
+        let key = GenericArray::from(key);
+        let aes = aes::Aes128::new(&key);
+
+        let mut block = GenericArray::from(block);
+        aes.decrypt_block(&mut block);
+        <[u8; 16]>::from(block)
+    }
+}

src/lib.rs

@@ -1,2 +1,4 @@
+#![feature(array_chunks)]
+pub mod friendly;
 pub mod english;
 pub mod prelude;

src/prelude.rs

@@ -25,6 +25,7 @@ macro_rules! bvecs {
 
 #[derive(Debug)]
 pub enum PreludeError {
+    WrongLength(usize),
     B64Err(base64::DecodeError),
     FHErr(hex::FromHexError),
     Utf8Err(std::str::Utf8Error),
@@ -40,13 +41,16 @@ pub trait ByteBased: Sized {
     fn from_b64(b: &str) -> CPals<Self>;
     fn to_b64(&self) -> String;
 
-    fn from_text(t: &str) -> Self;
+    fn from_text(t: &str) -> CPals<Self>;
     fn to_text(&self) -> CPals<&str>;
 
     fn xor_with(&self, other: &Self) -> CPals<Self>;
     fn xor_repeating(&self, other: &Self) -> CPals<Self>;
 
     fn hamming(&self, other: &Self) -> CPals<u64>;
+
+    fn to_fixed_len<const N: usize>(&self) -> CPals<[u8; N]>;
+    fn to_variable_len(&self) -> Vec<u8>;
 }
 
 impl ByteBased for Vec<u8> {
@@ -66,8 +70,8 @@ impl ByteBased for Vec<u8> {
         base64::engine::general_purpose::STANDARD.encode(self)
     }
 
-    fn from_text(tx: &str) -> Self {
-        tx.as_bytes().to_vec()
+    fn from_text(tx: &str) -> CPals<Self> {
+        Ok(tx.as_bytes().to_vec())
     }
 
     fn to_text(&self) -> CPals<&str> {
@@ -102,7 +106,83 @@ impl ByteBased for Vec<u8> {
         }
         Ok(bdist)
     }
+
+    fn to_fixed_len<const N: usize>(&self) -> CPals<[u8; N]> {
+        if self.len() != N {
+            return Err(PreludeError::WrongLength(self.len()))
         }
+        // avoid the owned requirement for [u8; N]
+        Ok(*self.array_chunks().next().unwrap())
+    }
+
+    fn to_variable_len(&self) -> Vec<u8> {
+        self.clone()
+    }
+}
+
+impl<const N: usize> ByteBased for [u8; N] {
+    fn from_hex(h: &str) -> CPals<Self> {
+        let v = <Vec<u8>>::from_hex(h)?;
+        v.to_fixed_len()
+    }
+
+    fn to_hex(&self) -> String {
+        self.to_variable_len().to_hex()
+    }
+
+    fn from_b64(b: &str) -> CPals<Self> {
+        let v = <Vec<u8>>::from_b64(b)?;
+        v.to_fixed_len()
+    }
+
+    fn to_b64(&self) -> String {
+        self.to_variable_len().to_b64()
+    }
+
+    fn from_text(t: &str) -> CPals<Self> {
+        let v = <Vec<u8>>::from_text(t)?;
+        v.to_fixed_len()
+    }
+
+    fn to_text(&self) -> CPals<&str> {
+        std::str::from_utf8(self).map_err(PreludeError::Utf8Err)
+    }
+
+    fn xor_with(&self, other: &Self) -> CPals<Self> {
+        let mut result = [0; N];
+        for i in 0..N {
+            result[i] = self[i] ^ other[i];
+        }
+        Ok(result)
+    }
+
+    fn xor_repeating(&self, other: &Self) -> CPals<Self> {
+        self.xor_with(other) // they necessarily have the same length
+    }
+
+    fn hamming(&self, other: &Self) -> CPals<u64> {
+        let mut count: u64 = 0;
+
+        for i in 0..N {
+            count += (self[i] ^ other[i]).count_ones() as u64;
+        }
+
+        Ok(count)
+    }
+
+    fn to_fixed_len<const N2: usize>(&self) -> CPals<[u8; N2]> {
+        let slice: &[u8] = self;
+        if let Ok(x) = <&[u8; N2]>::try_from(slice) {
+            return Ok(*x)
+        }
+        return Err(PreludeError::WrongLength(self.len())) 
+    }
+
+    fn to_variable_len(&self) -> Vec<u8> {
+        self.to_vec()
+    }
+}
+
 
 pub fn remove_ws(s: &str) -> String {
     let mut new = String::with_capacity(s.len());