argon2: use Block::SIZE constant (RustCrypto#161)

Also deprecates the previous `argon2::BLOCK_SIZE` constant.

Author: tarcieri

argon2/src/block.rs

@@ -1,6 +1,5 @@
 //! Argon2 memory block functions
 
-use crate::BLOCK_SIZE;
 use core::{
     convert::TryInto,
     num::Wrapping,
@@ -11,62 +10,23 @@ use core::{
 #[cfg(feature = "zeroize")]
 use zeroize::Zeroize;
 
-/// Quadwords in block
-const QWORDS_IN_BLOCK: usize = BLOCK_SIZE / 8;
-
 /// Structure for the (1KB) memory block implemented as 128 64-bit words.
 #[derive(Copy, Clone, Debug)]
-pub(crate) struct Block([u64; QWORDS_IN_BLOCK]);
+pub(crate) struct Block([u64; Self::SIZE / 8]);
 
 impl Default for Block {
     fn default() -> Self {
-        Self([0u64; QWORDS_IN_BLOCK])
-    }
-}
-
-impl BitXor for Block {
-    type Output = Self;
-
-    fn bitxor(self, rhs: Self) -> Self::Output {
-        let mut res = self;
-        res ^= rhs;
-        res
-    }
-}
-
-impl BitXorAssign for Block {
-    fn bitxor_assign(&mut self, rhs: Self) {
-        for (a, b) in self.iter_mut().zip(rhs.iter()) {
-            *a ^= *b;
-        }
-    }
-}
-
-impl Index<usize> for Block {
-    type Output = u64;
-
-    fn index(&self, index: usize) -> &u64 {
-        &self.0[index]
-    }
-}
-
-impl IndexMut<usize> for Block {
-    fn index_mut(&mut self, index: usize) -> &mut u64 {
-        &mut self.0[index]
-    }
-}
-
-#[cfg(feature = "zeroize")]
-impl Zeroize for Block {
-    fn zeroize(&mut self) {
-        self.0.zeroize();
+        Self([0u64; Self::SIZE / 8])
     }
 }
 
 impl Block {
+    /// Memory block size in bytes
+    pub const SIZE: usize = 1024;
+
     /// Load a block from a block-sized byte slice
     pub fn load(&mut self, input: &[u8]) {
-        debug_assert_eq!(input.len(), BLOCK_SIZE);
+        debug_assert_eq!(input.len(), Block::SIZE);
 
         for (i, chunk) in input.chunks(8).enumerate() {
             self[i] = u64::from_le_bytes(chunk.try_into().unwrap());
@@ -97,6 +57,13 @@ impl Block {
             // block_tmp = ref_block + prev_block + next_block
         }
 
+        /// Designed by the Lyra PHC team
+        fn blake2_mult(x: u64, y: u64) -> u64 {
+            let m = 0xFFFFFFFF;
+            let xy = Wrapping((x & m) * (y & m)) * Wrapping(2);
+            (Wrapping(x) + Wrapping(y) + xy).0
+        }
+
         /// Blake2 round function
         // TODO(tarcieri): use the `blake2` crate
         macro_rules! blake2_round {
@@ -178,9 +145,41 @@ impl Block {
     }
 }
 
-/// Designed by the Lyra PHC team
-fn blake2_mult(x: u64, y: u64) -> u64 {
-    let m = 0xFFFFFFFF;
-    let xy = Wrapping((x & m) * (y & m)) * Wrapping(2);
-    (Wrapping(x) + Wrapping(y) + xy).0
+impl BitXor for Block {
+    type Output = Self;
+
+    fn bitxor(self, rhs: Self) -> Self::Output {
+        let mut res = self;
+        res ^= rhs;
+        res
+    }
+}
+
+impl BitXorAssign for Block {
+    fn bitxor_assign(&mut self, rhs: Self) {
+        for (a, b) in self.iter_mut().zip(rhs.iter()) {
+            *a ^= *b;
+        }
+    }
+}
+
+impl Index<usize> for Block {
+    type Output = u64;
+
+    fn index(&self, index: usize) -> &u64 {
+        &self.0[index]
+    }
+}
+
+impl IndexMut<usize> for Block {
+    fn index_mut(&mut self, index: usize) -> &mut u64 {
+        &mut self.0[index]
+    }
+}
+
+#[cfg(feature = "zeroize")]
+impl Zeroize for Block {
+    fn zeroize(&mut self) {
+        self.0.zeroize();
+    }
 }

argon2/src/instance.rs

@@ -1,8 +1,7 @@
 //! Argon2 instance (i.e. state)
 
 use crate::{
-    Algorithm, Argon2, Block, Error, Memory, Version, BLOCK_SIZE, MAX_OUTLEN, MIN_OUTLEN,
-    SYNC_POINTS,
+    Algorithm, Argon2, Block, Error, Memory, Version, MAX_OUTLEN, MIN_OUTLEN, SYNC_POINTS,
 };
 use blake2::{
     digest::{self, VariableOutput},
@@ -201,7 +200,7 @@ impl<'a> Instance<'a> {
         }
 
         // Hash the result
-        let mut blockhash_bytes = [0u8; BLOCK_SIZE];
+        let mut blockhash_bytes = [0u8; Block::SIZE];
 
         for (chunk, v) in blockhash_bytes.chunks_mut(8).zip(blockhash.iter()) {
             chunk.copy_from_slice(&v.to_le_bytes())
@@ -220,7 +219,7 @@ impl<'a> Instance<'a> {
 
     /// Function creates first 2 blocks per lane
     fn fill_first_blocks(&mut self, blockhash: &[u8]) -> Result<(), Error> {
-        let mut hash = [0u8; BLOCK_SIZE];
+        let mut hash = [0u8; Block::SIZE];
 
         for l in 0..self.lanes {
             // Make the first and second block in each lane as G(H0||0||i) or

argon2/src/lib.rs

@@ -123,10 +123,10 @@ pub const MIN_OUTLEN: usize = 4;
 /// Maximum digest size in bytes
 pub const MAX_OUTLEN: usize = 0xFFFFFFFF;
 
-/// Minimum number of memory blocks (each of [`BLOCK_SIZE`] bytes)
+/// Minimum number of memory blocks.
 pub const MIN_MEMORY: u32 = 2 * SYNC_POINTS; // 2 blocks per slice
 
-/// Maximum number of memory blocks (each of [`BLOCK_SIZE`] bytes)
+/// Maximum number of memory blocks.
 pub const MAX_MEMORY: u32 = 0x0FFFFFFF;
 
 /// Minimum number of passes
@@ -151,7 +151,8 @@ pub const MAX_SALT_LENGTH: usize = 0xFFFFFFFF;
 pub const MAX_SECRET: usize = 0xFFFFFFFF;
 
 /// Memory block size in bytes
-pub const BLOCK_SIZE: usize = 1024;
+#[deprecated(since = "0.1.6", note = "use Block::SIZE instead")]
+pub const BLOCK_SIZE: usize = Block::SIZE;
 
 /// Argon2d algorithm identifier
 #[cfg(feature = "password-hash")]