cipher: restore allocating padded encrypt/decrypt

Signed-off-by: Marc-Antoine Perennou <Marc-Antoine@Perennou.com>

cipher/CHANGELOG.md

@@ -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).
 
+## UNRELEASED
+### Added
+- Allocating padded encrypt/decrypt ([#936])
+
+[#936]: https://github.com/RustCrypto/traits/pull/936
+
 ## 0.3.0 (2022-02-10)
 ### Changed
 - Major rework of traits. Core functionality of block and stream ciphers

cipher/Cargo.toml

@@ -25,7 +25,9 @@ blobby = { version = "0.3", optional = true }
 zeroize = { version = "1.5", optional = true, default-features = false }
 
 [features]
-std = ["crypto-common/std", "inout/std"]
+default = ["alloc"]
+alloc = []
+std = ["alloc", "crypto-common/std", "inout/std"]
 block-padding = ["inout/block-padding"]
 rand_core = ["crypto-common/rand_core"] # Enable random key and IV generation methods
 dev = ["blobby"]

cipher/src/block.rs

@@ -11,6 +11,8 @@
 //! [3]: https://en.wikipedia.org/wiki/Symmetric-key_algorithm
 
 use crate::{ParBlocks, ParBlocksSizeUser};
+#[cfg(all(feature = "block-padding", feature = "alloc"))]
+use alloc::{vec, vec::Vec};
 #[cfg(feature = "block-padding")]
 use inout::{
     block_padding::{Padding, UnpadError},
@@ -173,6 +175,17 @@ pub trait BlockEncrypt: BlockSizeUser + Sized {
         let buf = InOutBufReserved::from_slices(msg, out_buf).map_err(|_| PadError)?;
         self.encrypt_padded_inout::<P>(buf)
     }
+
+    /// Pad input and encrypt into a newly allocated Vec. Returns resulting ciphertext Vec.
+    #[cfg(all(feature = "block-padding", feature = "alloc"))]
+    #[cfg_attr(docsrs, doc(cfg(all(feature = "block-padding", feature = "alloc"))))]
+    #[inline]
+    fn encrypt_padded_vec<P: Padding<Self::BlockSize>>(&self, msg: &[u8]) -> Vec<u8> {
+        let mut out = allocate_out_vec::<Self>(msg.len());
+        self.encrypt_padded_b2b::<P>(msg, &mut out)
+            .expect("enough space for encrypting is allocated");
+        out
+    }
 }
 
 /// Decrypt-only functionality for block ciphers.
@@ -281,6 +294,24 @@ pub trait BlockDecrypt: BlockSizeUser {
         let buf = InOutBuf::new(in_buf, &mut out_buf[..n]).map_err(|_| UnpadError)?;
         self.decrypt_padded_inout::<P>(buf)
     }
+
+    /// Decrypt input and unpad it in a newly allocated Vec. Returns resulting
+    /// ciphertext Vec.
+    ///
+    /// Returns [`UnpadError`] if padding is malformed or if input length is
+    /// not multiple of `Self::BlockSize`.
+    #[cfg(all(feature = "block-padding", feature = "alloc"))]
+    #[cfg_attr(docsrs, doc(cfg(all(feature = "block-padding", feature = "alloc"))))]
+    #[inline]
+    fn decrypt_padded_vec<P: Padding<Self::BlockSize>>(
+        &self,
+        buf: &[u8],
+    ) -> Result<Vec<u8>, UnpadError> {
+        let mut out = vec![0; buf.len()];
+        let len = self.decrypt_padded_b2b::<P>(buf, &mut out)?.len();
+        out.truncate(len);
+        Ok(out)
+    }
 }
 
 /// Encrypt-only functionality for block ciphers and modes with mutable access to `self`.
@@ -386,6 +417,17 @@ pub trait BlockEncryptMut: BlockSizeUser + Sized {
         let buf = InOutBufReserved::from_slices(msg, out_buf).map_err(|_| PadError)?;
         self.encrypt_padded_inout_mut::<P>(buf)
     }
+
+    /// Pad input and encrypt into a newly allocated Vec. Returns resulting ciphertext Vec.
+    #[cfg(all(feature = "block-padding", feature = "alloc"))]
+    #[cfg_attr(docsrs, doc(cfg(all(feature = "block-padding", feature = "alloc"))))]
+    #[inline]
+    fn encrypt_padded_vec_mut<P: Padding<Self::BlockSize>>(self, msg: &[u8]) -> Vec<u8> {
+        let mut out = allocate_out_vec::<Self>(msg.len());
+        self.encrypt_padded_b2b_mut::<P>(msg, &mut out)
+            .expect("enough space for encrypting is allocated");
+        out
+    }
 }
 
 /// Decrypt-only functionality for block ciphers and modes with mutable access to `self`.
@@ -498,6 +540,24 @@ pub trait BlockDecryptMut: BlockSizeUser + Sized {
         let buf = InOutBuf::new(in_buf, &mut out_buf[..n]).map_err(|_| UnpadError)?;
         self.decrypt_padded_inout_mut::<P>(buf)
     }
+
+    /// Decrypt input and unpad it in a newly allocated Vec. Returns resulting
+    /// ciphertext Vec.
+    ///
+    /// Returns [`UnpadError`] if padding is malformed or if input length is
+    /// not multiple of `Self::BlockSize`.
+    #[cfg(all(feature = "block-padding", feature = "alloc"))]
+    #[cfg_attr(docsrs, doc(cfg(all(feature = "block-padding", feature = "alloc"))))]
+    #[inline]
+    fn decrypt_padded_vec<P: Padding<Self::BlockSize>>(
+        self,
+        buf: &[u8],
+    ) -> Result<Vec<u8>, UnpadError> {
+        let mut out = vec![0; buf.len()];
+        let len = self.decrypt_padded_b2b_mut::<P>(buf, &mut out)?.len();
+        out.truncate(len);
+        Ok(out)
+    }
 }
 
 impl<Alg: BlockEncrypt> BlockEncryptMut for Alg {
@@ -568,6 +628,12 @@ impl<'inp, 'out, BS: ArrayLength<u8>> BlockClosure for BlocksCtx<'inp, 'out, BS>
     }
 }
 
+#[cfg(all(feature = "block-padding", feature = "alloc"))]
+fn allocate_out_vec<BS: BlockSizeUser>(len: usize) -> Vec<u8> {
+    let bs = BS::BlockSize::USIZE;
+    vec![0; bs * (len / bs + 1)]
+}
+
 /// Implement simple block backend
 #[macro_export]
 macro_rules! impl_simple_block_encdec {

cipher/src/lib.rs

@@ -17,6 +17,9 @@
 pub use crypto_common;
 pub use inout;
 
+#[cfg(all(feature = "block-padding", feature = "alloc"))]
+extern crate alloc;
+
 #[cfg(feature = "std")]
 extern crate std;