Note heapless support in aead, chacha20poly1305 crates

Author: tarcieri

content/2019-11-28-newsletter-21.md

@@ -47,6 +47,8 @@ If you want to mention something in [the next newsletter], send us a pull reques
     - Tutorial 11: [Virtual Memory](https://github.com/rust-embedded/rust-raspi3-OS-tutorials/tree/master/11_virtual_memory)
     - Tutorial 12: [CPU Exceptions: Part 1](https://github.com/rust-embedded/rust-raspi3-OS-tutorials/tree/master/12_cpu_exceptions_part1)
 
+- [@tarcieri] released [`aead`] v0.2, providing generic traits for Authenticated Encryption with Associated Data (AEAD) ciphers, which now supports [ergonomic `alloc`-free operation][aead-heapless] via an integration with the [`heapless`] crate. This trait is now implemented by [several crates providing pure Rust implementations of AEAD modes][aead-crates] which may be interesting to embedded users seeking to encrypt/data data in `heapless` buffers, including the [`chacha20poly1305`] and [`aes-siv`] crates (and forthcoming support in the [`aes-ccm`] crate).
+
 <!-- TODO Add news about embedded projects here -->
 
 If you have an embedded project or blog post you would like to have featured in the Embedded WG Newsletter, make sure to add it to [the next newsletter], we would love to show it off!
@@ -58,6 +60,14 @@ If you have an embedded project or blog post you would like to have featured in
 [@japaric]: https://github.com/japaric
 [`ufmt`]: https://crates.io/crates/ufmt/0.1.0
 [@andre-richter]: https://github.com/andre-richter
+[@tarcieri]: https://github.com/tarcieri
+[`aead`]: https://docs.rs/aead
+[`heapless`]: https://docs.rs/heapless
+[aead-heapless]: https://docs.rs/chacha20poly1305/0.3.0/chacha20poly1305/#in-place-usage-eliminates-alloc-requirement
+[aead-crates]: https://github.com/rustcrypto/aeads#crates
+[`chacha20poly1305`]: https://docs.rs/chacha20poly1305/
+[`aes-siv`]: https://docs.rs/aes-siv/
+[`aes-ccm`]: https://github.com/martindisch/aes-ccm/issues/2
 
 ## `embedded-hal` Ecosystem Crates