diff --git a/README.md b/README.md
index deb9026ca..25a848b0a 100644
--- a/README.md
+++ b/README.md
@@ -38,10 +38,20 @@ packages.
 ```
 clang
 openssl-devel
+```
+
+If using feature `did-webkey/sequoia-openpgp` for PGP support, the following
+dependencies are also needed:
+
+```
 nettle-dev
 capnproto
 ```
 
+If using feature
+[`did-webkey/crypto-cng`](https://gitlab.com/sequoia-pgp/sequoia#cryptography),
+only `capnproto` is needed.
+
 ## Install
 
 ### Crates.io