README.md: remove (toplevel) security warning

We're now in a state where `aes-gcm` and `chacha20poly1305` have been
audited, but the other implementations have not.

Every crate already carries its own notice about whether it has or has
not been audited, so this commit removes the toplevel notice.

README.md

@@ -4,13 +4,6 @@
 Collection of [Authenticated Encryption with Associated Data (AEAD)][AEAD]
 algorithms written in pure Rust.
 
-## Warnings
-
-Crates in this repository have not yet received any formal cryptographic and
-security reviews.
-
-**USE AT YOUR OWN RISK.**
-
 ## Usage
 
 Crates functionality is expressed in terms of traits defined in the [`aead`]
@@ -23,6 +16,7 @@ crate.
 | [`aes-gcm-siv`]      | [AES-GCM-SIV](https://en.wikipedia.org/wiki/AES-GCM-SIV) | [![crates.io](https://img.shields.io/crates/v/aes-gcm-siv.svg)](https://crates.io/crates/aes-gcm-siv) | [![Documentation](https://docs.rs/aes-gcm-siv/badge.svg)](https://docs.rs/aes-gcm-siv) |
 | [`aes-siv`]          |[AES-SIV](https://github.com/miscreant/meta/wiki/AES-SIV) | [![crates.io](https://img.shields.io/crates/v/aes-siv.svg)](https://crates.io/crates/aes-siv) | [![Documentation](https://docs.rs/aes-siv/badge.svg)](https://docs.rs/aes-siv) |
 | [`chacha20poly1305`] | [(X)ChaCha20Poly1305](https://tools.ietf.org/html/rfc8439) | [![crates.io](https://img.shields.io/crates/v/chacha20poly1305.svg)](https://crates.io/crates/chacha20poly1305) | [![Documentation](https://docs.rs/chacha20poly1305/badge.svg)](https://docs.rs/chacha20poly1305) |
+| [`crypto_box`]       | [Curve25519XSalsa20Poly1305](https://nacl.cr.yp.to/box.html) | [![crates.io](https://img.shields.io/crates/v/crypto_box.svg)](https://crates.io/crates/crypto_box) | [![Documentation](https://docs.rs/crypto_box/badge.svg)](https://docs.rs/crypto_box)
 | [`xsalsa20poly1305`] | [XSalsa20Poly1305](https://nacl.cr.yp.to/secretbox.html) | [![crates.io](https://img.shields.io/crates/v/xsalsa20poly1305.svg)](https://crates.io/crates/xsalsa20poly1305) | [![Documentation](https://docs.rs/xsalsa20poly1305/badge.svg)](https://docs.rs/xsalsa20poly1305) |
 
 NOTE: the [`aes-ccm`] crate also implements the [`aead`] traits
@@ -50,10 +44,11 @@ dual licensed as above, without any additional terms or conditions.
 
 [AEAD]: https://en.wikipedia.org/wiki/Authenticated_encryption
 [`aead`]: https://docs.rs/aead
+[`aes-ccm`]: https://crates.io/crates/aes-ccm
 [`aes-gcm`]: https://github.com/RustCrypto/AEADs/tree/master/aes-gcm
 [`aes-gcm-siv`]: https://github.com/RustCrypto/AEADs/tree/master/aes-gcm-siv
 [`aes-siv`]: https://github.com/RustCrypto/AEADs/tree/master/aes-siv
 [`chacha20poly1305`]: https://github.com/RustCrypto/AEADs/tree/master/chacha20poly1305
+[`crypto_box`]: https://github.com/RustCrypto/AEADs/tree/master/crypto_box
 [`xsalsa20poly1305`]: https://github.com/RustCrypto/AEADs/tree/master/xsalsa20poly1305 
-[`aes-ccm`]: https://crates.io/crates/aes-ccm