keyfork-mnemonic-generate/src/main.rs

@@ -76,34 +76,32 @@ fn build_wordlist() -> Vec<String> {
         .collect()
 }
 
-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
+#[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 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 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 main() -> Result<(), Box<dyn Error>> {
@@ -135,8 +133,18 @@ fn main() -> Result<(), Box<dyn Error>> {
     let entropy = &mut [0u8; 256 / 8];
     random_handle.read_exact(&mut entropy[..])?;
 
-    let seed_bits = entropy_to_bits(entropy);
+    let hash = generate_slice_hash(entropy);
+    let checksum = u8_to_bitslice(&hash[1]);
 
+    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())
@@ -171,8 +179,14 @@ mod tests {
                 panic!("bad test: {test}");
             };
             let hex = hex::decode(hex_.as_str().unwrap()).unwrap();
-
-            let seed_bits = entropy_to_bits(&hex);
+            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 words = seed_bits
                 .chunks_exact(11)
@@ -180,8 +194,7 @@ mod tests {
                     wordlist[bitslice_to_usize(chunk.try_into().expect("11 bit chunks"))].clone()
                 })
                 .collect::<Vec<_>>();
-
-            assert_eq!(words.join(" "), seed.as_str().unwrap());
+            panic!("{}", words.join(" "));
         }
         Ok(())
     }