Add NonceSize to FromBlockCipher (#209)

Author: newpavlov

Cargo.lock

@@ -5,6 +5,12 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## 0.2.0 (2020-07-03)
+### Changed
+- Bump `stream-cipher` to v0.5 ([#209])
+
+[#209]: https://github.com/RustCrypto/traits/pull/209
+
 ## 0.1.4 (2020-06-21)
 ### Added
 - rustdoc improvements ([#205])

cryptography/CHANGELOG.md

@@ -1,6 +1,6 @@
 [package]
 name = "cryptography"
-version = "0.1.4"
+version = "0.2.0"
 authors = ["The RustCrypto Project Developers"]
 license = "Apache-2.0 OR MIT"
 description = "Facade crate for the RustCrypto project's traits"
@@ -17,7 +17,7 @@ block-cipher = { version = "0.7", optional = true, path = "../block-cipher" }
 digest = { version = "0.9", optional = true, path = "../digest" }
 mac = { version = "0.8", package = "crypto-mac", optional = true, path = "../crypto-mac" }
 signature = { version = "1.1.0", optional = true, default-features = false, path = "../signature" }
-stream-cipher = { version = "0.4", optional = true, path = "../stream-cipher" }
+stream-cipher = { version = "0.5", optional = true, path = "../stream-cipher" }
 universal-hash = { version = "0.4", optional = true, path = "../universal-hash" }
 
 [package.metadata.docs.rs]

cryptography/Cargo.toml

@@ -5,6 +5,12 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## 0.5.0 (2020-07-03)
+### Changed
+- Add `NonceSize` associated type to the `FromBlockCipher` trait ([#209])
+
+[#209]: https://github.com/RustCrypto/traits/pull/209
+
 ## 0.4.1 (2020-06-10)
 ### Added
 - `Key` and `Nonce` type aliases ([#188])

stream-cipher/CHANGELOG.md

@@ -1,7 +1,7 @@
 [package]
 name = "stream-cipher"
 description = "Stream cipher traits"
-version = "0.4.1"
+version = "0.5.0"
 authors = ["RustCrypto Developers"]
 license = "MIT OR Apache-2.0"
 readme = "README.md"
@@ -21,6 +21,7 @@ optional = true
 path = "../block-cipher"
 
 [features]
+default = ["block-cipher"]
 std = []
 dev = ["blobby"]
 

stream-cipher/Cargo.toml

@@ -131,12 +131,14 @@ impl<C: SyncStreamCipher> StreamCipher for C {
 pub trait FromBlockCipher {
     /// Block cipher
     type BlockCipher: BlockCipher + NewBlockCipher;
+    /// Nonce size in bytes
+    type NonceSize: ArrayLength<u8>;
 
     /// Instantiate a stream cipher from a block cipher
     // TODO(tarcieri): add associated type for NonceSize?
     fn from_block_cipher(
         cipher: Self::BlockCipher,
-        nonce: &block_cipher::Block<Self::BlockCipher>,
+        nonce: &GenericArray<u8, Self::NonceSize>,
     ) -> Self;
 }
 
@@ -146,12 +148,25 @@ where
     C: FromBlockCipher,
 {
     type KeySize = <<Self as FromBlockCipher>::BlockCipher as NewBlockCipher>::KeySize;
-    type NonceSize = <<Self as FromBlockCipher>::BlockCipher as BlockCipher>::BlockSize;
+    type NonceSize = <Self as FromBlockCipher>::NonceSize;
 
     fn new(key: &Key<Self>, nonce: &Nonce<Self>) -> C {
         C::from_block_cipher(
             <<Self as FromBlockCipher>::BlockCipher as NewBlockCipher>::new(key),
             nonce,
         )
     }
+
+    fn new_var(key: &[u8], nonce: &[u8]) -> Result<Self, InvalidKeyNonceLength> {
+        if nonce.len() != Self::NonceSize::USIZE {
+            Err(InvalidKeyNonceLength)
+        } else {
+            C::BlockCipher::new_varkey(key)
+                .map_err(|_| InvalidKeyNonceLength)
+                .map(|cipher| {
+                    let nonce = GenericArray::from_slice(nonce);
+                    Self::from_block_cipher(cipher, nonce)
+                })
+        }
+    }
 }