diff --git a/Cargo.lock b/Cargo.lock
index ee79919d0..e2f7fec8d 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -139,6 +139,15 @@ version = "0.1.0-rc.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "11a8c0210fa48ba3ea04ac1e9c6e72ae66009db3b1f1745635d4ff2e58eaadd0"
 
+[[package]]
+name = "cpufeatures"
+version = "0.2.17"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "59ed5838eebb26a2bb2e58f6d5b5316989ae9d08bab10e0e6d103e656d1b0280"
+dependencies = [
+ "libc",
+]
+
 [[package]]
 name = "critical-section"
 version = "1.2.0"
@@ -213,6 +222,7 @@ dependencies = [
  "block-buffer",
  "const-oid",
  "crypto-common",
+ "sha2",
  "subtle",
  "zeroize",
 ]
@@ -640,6 +650,17 @@ dependencies = [
  "serde",
 ]
 
+[[package]]
+name = "sha2"
+version = "0.11.0-rc.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7c5f3b1e2dc8aad28310d8410bd4d7e180eca65fca176c52ab00d364475d0024"
+dependencies = [
+ "cfg-if",
+ "cpufeatures",
+ "digest",
+]
+
 [[package]]
 name = "signature"
 version = "3.0.0-rc.10"
diff --git a/Cargo.toml b/Cargo.toml
index 960d86e17..79c85b5b2 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -22,7 +22,6 @@ cast_possible_wrap = "warn"
 cast_precision_loss = "warn"
 cast_sign_loss = "warn"
 checked_conversions = "warn"
-doc_markdown = "warn"
 from_iter_instead_of_collect = "warn"
 implicit_saturating_sub = "warn"
 manual_assert = "warn"
diff --git a/cipher/README.md b/cipher/README.md
index 310b0b3b6..d8b21522a 100644
--- a/cipher/README.md
+++ b/cipher/README.md
@@ -7,10 +7,10 @@
 [![Project Chat][chat-image]][chat-link]
 [![Build Status][build-image]][build-link]
 
-Traits which define the functionality of [block ciphers] and [stream ciphers].
+Traits which define the functionality of [block ciphers], [block modes] and [stream ciphers].
 
-See [RustCrypto/block-ciphers] and [RustCrypto/stream-ciphers] for algorithm
-implementations which use these traits.
+See [RustCrypto/block-ciphers] and [RustCrypto/stream-ciphers] for algorithm implementations which
+use these traits.
 
 ## SemVer Policy
 
@@ -48,6 +48,7 @@ dual licensed as above, without any additional terms or conditions.
 [//]: # (general links)
 
 [block ciphers]: https://en.wikipedia.org/wiki/Block_cipher
+[block modes]: https://en.wikipedia.org/wiki/Block_cipher_mode_of_operation
 [stream ciphers]: https://en.wikipedia.org/wiki/Stream_cipher
 [RustCrypto/block-ciphers]: https://github.com/RustCrypto/block-ciphers
 [RustCrypto/stream-ciphers]: https://github.com/RustCrypto/stream-ciphers
diff --git a/cipher/src/lib.rs b/cipher/src/lib.rs
index 7621062bd..2146eeec2 100644
--- a/cipher/src/lib.rs
+++ b/cipher/src/lib.rs
@@ -1,12 +1,6 @@
-//! This crate defines a set of traits which describe the functionality of
-//! [block ciphers][1], [block modes][2], and [stream ciphers][3].
-//!
-//! [1]: https://en.wikipedia.org/wiki/Block_cipher
-//! [2]: https://en.wikipedia.org/wiki/Block_cipher_mode_of_operation
-//! [3]: https://en.wikipedia.org/wiki/Stream_cipher
-
 #![no_std]
 #![cfg_attr(docsrs, feature(doc_cfg))]
+#![doc = include_str!("../README.md")]
 #![doc(
     html_logo_url = "https://raw.githubusercontent.com/RustCrypto/media/6ee8e381/logo.svg",
     html_favicon_url = "https://raw.githubusercontent.com/RustCrypto/media/6ee8e381/logo.svg"
diff --git a/crypto-common/src/lib.rs b/crypto-common/src/lib.rs
index 2ee4fe5b2..f3e1b58f7 100644
--- a/crypto-common/src/lib.rs
+++ b/crypto-common/src/lib.rs
@@ -1,13 +1,11 @@
-//! Common cryptographic traits.
-
 #![no_std]
 #![cfg_attr(docsrs, feature(doc_cfg))]
+#![doc = include_str!("../README.md")]
 #![doc(
     html_logo_url = "https://raw.githubusercontent.com/RustCrypto/media/6ee8e381/logo.svg",
     html_favicon_url = "https://raw.githubusercontent.com/RustCrypto/media/6ee8e381/logo.svg"
 )]
 #![forbid(unsafe_code)]
-#![warn(missing_docs, rust_2018_idioms, missing_debug_implementations)]
 
 /// Hazardous materials.
 pub mod hazmat;
diff --git a/digest/Cargo.toml b/digest/Cargo.toml
index 0fde96241..30e0165f7 100644
--- a/digest/Cargo.toml
+++ b/digest/Cargo.toml
@@ -22,6 +22,9 @@ blobby = { version = "0.4", optional = true }
 const-oid = { version = "0.10", optional = true }
 zeroize = { version = "1.7", optional = true, default-features = false }
 
+[dev-dependencies]
+sha2 = "0.11.0-rc.5"
+
 [features]
 default = ["block-api"]
 block-api = ["block-buffer"] # Enable block API traits
diff --git a/digest/README.md b/digest/README.md
index e17da08b0..584f95bf4 100644
--- a/digest/README.md
+++ b/digest/README.md
@@ -39,7 +39,7 @@ hasher.update(data);
 hasher.update("String data");
 // Note that calling `finalize()` consumes hasher
 let hash = hasher.finalize();
-println!("Result: {:x}", hash);
+println!("Result: {:?}", hash);
 ```
 
 In this example `hash` has type [`Array<u8, U32>`][2], which is a generic
@@ -49,19 +49,23 @@ Alternatively you can use chained approach, which is equivalent to the previous
 example:
 
 ```rust
+use sha2::{Sha256, Digest};
+
 let hash = Sha256::new()
     .chain_update(b"Hello world!")
     .chain_update("String data")
     .finalize();
 
-println!("Result: {:x}", hash);
+println!("Result: {:?}", hash);
 ```
 
 If the whole message is available you also can use convenience `digest` method:
 
 ```rust
+use sha2::{Sha256, Digest};
+
 let hash = Sha256::digest(b"my message");
-println!("Result: {:x}", hash);
+println!("Result: {:?}", hash);
 ```
 
 ### Generic code
diff --git a/digest/src/lib.rs b/digest/src/lib.rs
index 1cb025341..0e2e64250 100644
--- a/digest/src/lib.rs
+++ b/digest/src/lib.rs
@@ -1,7 +1,16 @@
-//! This crate provides traits which describe functionality of cryptographic hash
-//! functions and Message Authentication algorithms.
+#![no_std]
+#![cfg_attr(docsrs, feature(doc_cfg))]
+#![doc = include_str!("../README.md")]
+#![forbid(unsafe_code)]
+#![doc(
+    html_logo_url = "https://raw.githubusercontent.com/RustCrypto/media/6ee8e381/logo.svg",
+    html_favicon_url = "https://raw.githubusercontent.com/RustCrypto/media/6ee8e381/logo.svg"
+)]
+#![warn(missing_docs, rust_2018_idioms, missing_debug_implementations)]
+
+//! ## Structure
 //!
-//! Traits in this repository are organized into the following levels:
+//! Traits in this crate are organized into the following levels:
 //!
 //! - **High-level convenience traits**: [`Digest`], [`DynDigest`], [`Mac`].
 //!   Wrappers around lower-level traits for most common use-cases. Users should
@@ -24,15 +33,6 @@
 //!
 //! [`digest-io`]: https://docs.rs/digest-io
 
-#![no_std]
-#![cfg_attr(docsrs, feature(doc_cfg))]
-#![forbid(unsafe_code)]
-#![doc(
-    html_logo_url = "https://raw.githubusercontent.com/RustCrypto/media/6ee8e381/logo.svg",
-    html_favicon_url = "https://raw.githubusercontent.com/RustCrypto/media/6ee8e381/logo.svg"
-)]
-#![warn(missing_docs, rust_2018_idioms, missing_debug_implementations)]
-
 #[cfg(feature = "alloc")]
 #[macro_use]
 extern crate alloc;
diff --git a/signature/src/lib.rs b/signature/src/lib.rs
index cc916868b..e0a7b3453 100644
--- a/signature/src/lib.rs
+++ b/signature/src/lib.rs
@@ -1,10 +1,10 @@
 #![no_std]
+#![cfg_attr(docsrs, feature(doc_cfg))]
 #![doc = include_str!("../README.md")]
 #![doc(
     html_logo_url = "https://raw.githubusercontent.com/RustCrypto/media/8f1a9894/logo.svg",
     html_favicon_url = "https://raw.githubusercontent.com/RustCrypto/media/8f1a9894/logo.svg"
 )]
-#![cfg_attr(docsrs, feature(doc_cfg))]
 #![forbid(unsafe_code)]
 #![allow(async_fn_in_trait)]
 #![warn(