keyfork-mnemonic-generate: fix endianness

keyfork-mnemonic-generate/src/main.rs

@@ -76,32 +76,34 @@ fn build_wordlist() -> Vec<String> {
         .collect()
 }
 
-#[allow(clippy::trivially_copy_pass_by_ref)]
-fn u8_to_bitslice(byte: &u8) -> [bool; 8] {
-    [
-        byte & (1 << 0) != 0,
-        byte & (1 << 1) != 0,
-        byte & (1 << 2) != 0,
-        byte & (1 << 3) != 0,
-        byte & (1 << 4) != 0,
-        byte & (1 << 5) != 0,
-        byte & (1 << 6) != 0,
-        byte & (1 << 7) != 0,
-    ]
+fn bitslice_to_usize(bitslice: [bool; 11]) -> usize {
+    let mut index = 0usize;
+    for i in 0..11 {
+        index += usize::from(bitslice[10 - i]) << i;
+    }
+    index
 }
 
-fn bitslice_to_usize(bitslice: [bool; 11]) -> usize {
-    usize::from(bitslice[10])
-        + (usize::from(bitslice[9]) << 1)
-        + (usize::from(bitslice[8]) << 2)
-        + (usize::from(bitslice[7]) << 3)
-        + (usize::from(bitslice[6]) << 4)
-        + (usize::from(bitslice[5]) << 5)
-        + (usize::from(bitslice[4]) << 6)
-        + (usize::from(bitslice[3]) << 7)
-        + (usize::from(bitslice[2]) << 8)
-        + (usize::from(bitslice[1]) << 9)
-        + (usize::from(bitslice[0]) << 10)
+fn entropy_to_bits(bytes: &[u8]) -> Vec<bool> {
+    let bit_count = bytes.len() * 8;
+    let hash = generate_slice_hash(bytes);
+
+    assert_eq!(bit_count % 32, 0, "bit count must be in 32 bit increments");
+
+    let mut bits = vec![false; bit_count + bit_count / 32];
+
+    for byte_index in 0..bit_count / 8 {
+        for bit_index in 0..8 {
+            bits[byte_index * 8 + bit_index] = (bytes[byte_index] & (1 << (7 - bit_index))) > 0;
+        }
+    }
+    for check_bit in 0..bit_count / 32 {
+        bits[bit_count + check_bit] = (hash[check_bit / 8] & (1 << (7 - (check_bit % 8)))) > 0;
+    }
+
+    assert_eq!(bits.len() % 11, 0, "unstable bit count");
+
+    bits
 }
 
 fn main() -> Result<(), Box<dyn Error>> {
@@ -133,18 +135,8 @@ fn main() -> Result<(), Box<dyn Error>> {
     let entropy = &mut [0u8; 256 / 8];
     random_handle.read_exact(&mut entropy[..])?;
 
-    let hash = generate_slice_hash(entropy);
-    let checksum = u8_to_bitslice(&hash[1]);
+    let seed_bits = entropy_to_bits(entropy);
 
-    let mut seed_bits = entropy[..bit_size / 8]
-        .iter()
-        .flat_map(u8_to_bitslice)
-        .collect::<Vec<_>>();
-    seed_bits.extend(if bit_size == 256 {
-        &checksum[..8]
-    } else {
-        &checksum[..4]
-    });
     let words = seed_bits
         .chunks_exact(11)
         .map(|chunk| wordlist[bitslice_to_usize(chunk.try_into().expect("11 bit chunks"))].clone())
@@ -179,14 +171,8 @@ mod tests {
                 panic!("bad test: {test}");
             };
             let hex = hex::decode(hex_.as_str().unwrap()).unwrap();
-            let hash = generate_slice_hash(&hex);
-            let checksum = u8_to_bitslice(&hash.iter().next().unwrap());
-            let mut seed_bits = hex.iter().flat_map(u8_to_bitslice).collect::<Vec<_>>();
-            seed_bits.extend(if hex.len() == 256 / 8 {
-                &checksum[..8]
-            } else {
-                &checksum[..4]
-            });
+
+            let seed_bits = entropy_to_bits(&hex);
 
             let words = seed_bits
                 .chunks_exact(11)
@@ -194,7 +180,8 @@ mod tests {
                     wordlist[bitslice_to_usize(chunk.try_into().expect("11 bit chunks"))].clone()
                 })
                 .collect::<Vec<_>>();
-            panic!("{}", words.join(" "));
+
+            assert_eq!(words.join(" "), seed.as_str().unwrap());
         }
         Ok(())
     }