feat(crypto): document package feature flags

GUIDELINES.md

@@ -117,7 +117,8 @@ This is enforced by `rustfmt`. Note that this is a `nightly` feature.
 
 ### Variable naming
 
-Use short 1-letter names when the variable scope is only a few lines, or the context is
+Use short 1-letter names when the variable scope is only a few lines, or the
+context is
 obvious, eg.
 
 ```rust
@@ -148,10 +149,10 @@ and/or object and repeating that would be redundant.
 
 ## Dependencies
 
-Before adding any code dependencies, check with the maintainers if this is okay.
-In general, we try not to add external dependencies unless it's necessary.
-Dependencies increase counter-party risk, build-time, attack surface, and
-make code harder to audit.
+Before adding any code dependencies, check with the maintainers if this is
+okay. In general, we try not to add external dependencies unless it's
+necessary. Dependencies increase counter-party risk, build-time, attack
+surface, and make code harder to audit.
 
 We also optimize for binary size, which means we try to keep generated code to
 a minimum and adding dependencies is one of the biggest sources of code bloat.

SECURITY.md

@@ -1,6 +1,8 @@
 # Security
 
-> ⚠️ Warning! ⚠️
-> This project is still in a very early and experimental phase. It has never been audited nor thoroughly reviewed for security vulnerabilities. Do not use in production.
+> [!WARNING]
+> This project is still in a very early and experimental phase. It has never
+> been audited nor thoroughly reviewed for security vulnerabilities. Do not use
+> in production.
 
 Please report any security issues you find to [email protected].

lib/crypto/README.md

@@ -2,17 +2,24 @@
 
 Common cryptographic procedures for a blockchain environment.
 
-> [!WARNING] `crypto` is still `0.*.*`, so breaking changes
+> [!WARNING]
+> Note that `crypto` is still `0.*.*`, so breaking changes
 > [may occur at any time](https://semver.org/#spec-item-4). If you must depend
 > on `crypto`, we recommend pinning to a specific version, i.e., `=0.y.z`.
 
 ## Verifying Merkle Proofs
 
 [`merkle.rs`](lib/crypto/src/merkle.rs) provides:
 
-* A `verify` function which can prove that some value is part of a [Merkle tree].
-* A `verify_multi_proof` function which can prove multiple values are part of a [Merkle tree].
+- A `verify` function which can prove that some value is part of a
+  [Merkle tree].
+- A `verify_multi_proof` function which can prove multiple values are part of a
+  [Merkle tree].
 
 [Merkle tree]: https://en.wikipedia.org/wiki/Merkle_tree
 
-TODO: Document feature flags.
+## Feature Flags
+
+This crate exposes its modules behind feature gates to ensure the bare minimum
+is included in consumer condebases. You can check the current feature flags in
+the [Cargo.toml](./Cargo.toml) file.