feat(cli): make flat command structure

des/src/des.rs

@@ -37,6 +37,10 @@ impl Des {
 impl BlockCipher for Des {
     const BLOCK_SIZE: usize = 8;
 
+    fn from_key(key: &[u8]) -> Self {
+        Self::new(key)
+    }
+
     fn transform_impl(
         &self,
         block: &[u8],

des/src/key/des_key.rs

@@ -31,6 +31,21 @@ impl From<[u8; 8]> for Key {
     }
 }
 
+impl From<&[u8]> for Key {
+    fn from(value: &[u8]) -> Self {
+        let mut bytes = [0; 8];
+        let len = value.len().min(8);
+        bytes[..len].copy_from_slice(&value[..len]);
+        Self(bytes)
+    }
+}
+
+impl From<u64> for Key {
+    fn from(key: u64) -> Self {
+        Self(key.to_be_bytes())
+    }
+}
+
 impl From<Key> for [u8; 8] {
     fn from(key: Key) -> Self {
         key.0
@@ -43,12 +58,6 @@ impl AsRef<[u8]> for Key {
     }
 }
 
-impl From<u64> for Key {
-    fn from(key: u64) -> Self {
-        Self(key.to_be_bytes())
-    }
-}
-
 impl Debug for Key {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         f.write_str("Key([REDACTED])")