Provide background on asymmetric crypto in index

1 files changed, 22 insertions, 0 deletions

diff --git a/docs/hazmat/primitives/asymmetric/index.rst b/docs/hazmat/primitives/asymmetric/index.rst
index dfa81d09..43761fde 100644
--- a/docs/hazmat/primitives/asymmetric/index.rst
+++ b/docs/hazmat/primitives/asymmetric/index.rst
@@ -3,6 +3,26 @@
 Asymmetric algorithms
 =====================
 
+Asymmetric cryptography is a branch of cryptography where a secret key can be
+divided into two parts, a :term:`public key` and a :term:`private key`. The
+public key can be given to anyone, trusted or not, while the private key must
+be kept secret (just like the key in symmetric cryptography).
+
+Asymmetric cryptography has two primary use cases: authentication and
+confidentiality. Using asymmetric cryptography, messages can be signed with a
+private key, and then anyone with the public key is able to verify that the
+message was created by someone possessing the corresponding private key. This
+can be combined with a `proof of identity`_ system to know what entity (person
+or group) actually owns that private key, providing authentication.
+
+Encryption with asymmetric cryptography works in a slightly different way from
+symmetric encryption. Someone with the public key is able to encrypt a message,
+providing confidentiality, and then only the person in possession of the
+private key is able to decrypt it.
+
+Cryptography supports three different sets of asymmetric algorithms: RSA, DSA,
+and Elliptic Curve.
+
 .. toctree::
     :maxdepth: 1
 
@@ -11,3 +31,5 @@ Asymmetric algorithms
     rsa
     serialization
     utils
+
+.. _`proof of identity`: https://en.wikipedia.org/wiki/Public-key_infrastructure