diff --git a/API.md b/API.md
new file mode 100644
index 0000000..3127e02
--- /dev/null
+++ b/API.md
@@ -0,0 +1,121 @@
+# API
+
+## `hmac`
+
+Exposes an interface to the Keyed-Hash Message Authentication Code (HMAC) as defined in U.S. Federal Information Processing Standards Publication 198. An HMAC is a cryptographic hash that uses a key to sign a message. The receiver verifies the hash by recomputing it using the same key.
+
+### `create(hash, secret, callback)`
+
+- `hash: String`
+- `secret: Buffer`
+- `callback: Function`
+
+#### `digest(data, callback)`
+
+- `data: Buffer`
+- `callback: Function`
+
+## `aes`
+Expoes an interface to AES encryption (formerly Rijndael), as defined in U.S. Federal Information Processing Standards Publication 197.
+
+This uses `CTR` mode.
+
+### `create(key, iv, callback)`
+
+- `key: Buffer` The key, if length `16` then `AES 128` is used. For length `32`, `AES 256` is used.
+- `iv: Buffer` Must have length `16`.
+- `callback: Function`
+
+#### `encrypt(data, callback)`
+
+- `data: Buffer`
+- `callback: Function`
+
+#### `encrypt(data, callback)`
+
+- `data: Buffer`
+- `callback: Function`
+
+
+## `webcrypto`
+
+Depending on the environment this is either an instance of [node-webcrypto-ossl](https://github.com/PeculiarVentures/node-webcrypto-ossl) or the result of `window.crypto`.
+
+## `keys`
+
+## `generateKeyPair(type, bits, callback)`
+
+- `type: String`, only `'RSA'` is currently supported
+- `bits: Number` Minimum of 1024
+- `callback: Function`
+
+Generates a keypair of the given type and bitsize.
+
+## `generateEphemeralKeyPair(curve, callback)`
+
+- `curve: String`, one of `'P-256'`, `'P-384'`, `'P-521'` is currently supported
+- `callback: Function`
+
+Generates an ephemeral public key and returns a function that will compute the shared secret key.
+
+Focuses only on ECDH now, but can be made more general in the future.
+
+Calls back with an object of the form
+
+```js
+{
+  key: Buffer,
+  genSharedKey: Function
+}
+```
+
+## `keyStretcher(cipherType, hashType, secret, callback)`
+
+- `cipherType: String`, one of `'AES-128'`, `'AES-256'`, `'Blowfish'`
+- `hashType: String`, one of `'SHA1'`, `SHA256`, `SHA512`
+- `secret: Buffer`
+- `callback: Function`
+
+Generates a set of keys for each party by stretching the shared key.
+
+Calls back with an object of the form
+```js
+{
+  k1: {
+    iv: Buffer,
+    cipherKey: Buffer,
+    macKey: Buffer
+  },
+  k2: {
+    iv: Buffer,
+    cipherKey: Buffer,
+    macKey: Buffer
+  }
+}
+```
+## `marshalPublicKey(key[, type], callback)`
+
+- `key: crypto.rsa.RsaPublicKey`
+- `type: String`, only `'RSA'` is currently supported
+
+Converts a public key object into a protobuf serialized public key.
+
+## `unmarshalPublicKey(buf)`
+
+- `buf: Buffer`
+
+Converts a protobuf serialized public key into its  representative object.
+
+## `marshalPrivateKey(key[, type])`
+
+- `key: crypto.rsa.RsaPrivateKey`
+- `type: String`, only `'RSA'` is currently supported
+
+Converts a private key object into a protobuf serialized private key.
+
+## `unmarshalPrivateKey(buf, callback)`
+
+- `buf: Buffer`
+- `callback: Function`
+
+Converts a protobuf serialized private key into its representative object.
diff --git a/README.md b/README.md
index 5dfd6a9..59a4046 100644
--- a/README.md
+++ b/README.md
@@ -21,13 +21,6 @@ needed for libp2p. This is based on this [go implementation](https://github.com/
 - [Usage](#usage)
   - [Example](#example)
 - [API](#api)
-  - [`generateKeyPair(type, bits, cb)`](#generatekeypairtype-bits-cb)
-  - [`generateEphemeralKeyPair(curve)`](#generateephemeralkeypaircurve)
-  - [`keyStretcher(cipherType, hashType, secret)`](#keystretcherciphertype-hashtype-secret)
-  - [`marshalPublicKey(key[, type])`](#marshalpublickeykey-type)
-  - [`unmarshalPublicKey(buf)`](#unmarshalpublickeybuf)
-  - [`marshalPrivateKey(key[, type])`](#marshalprivatekeykey-type)
-  - [`unmarshalPrivateKey(buf)`](#unmarshalprivatekeybuf)
 - [Contribute](#contribute)
 - [License](#license)
 
@@ -50,78 +43,7 @@ crypto.generateKeyPair('RSA', 2048, (err, key) => {
 
 ## API
 
-### `generateKeyPair(type, bits, cb)`
-
-- `type: String`, only `'RSA'` is currently supported
-- `bits: Number`
-- `cb: Function`
-
-Generates a keypair of the given type and bitsize.
-
-### `generateEphemeralKeyPair(curve)`
-
-- `curve: String`, one of `'P-256'`, `'P-384'`, `'P-521'` is currently supported
-
-Generates an ephemeral public key and returns a function that will compute the shared secret key.
-
-Focuses only on ECDH now, but can be made more general in the future.
-
-Returns an object of the form
-```js
-{
-  key: Buffer,
-  genSharedKey: Function
-}
-```
-
-### `keyStretcher(cipherType, hashType, secret)`
-
-- `cipherType: String`, one of `'AES-128'`, `'AES-256'`, `'Blowfish'`
-- `hashType: String`, one of `'SHA1'`, `SHA256`, `SHA512`
-- `secret: Buffer`
-
-Generates a set of keys for each party by stretching the shared key.
-
-Returns an object of the form
-```js
-{
-  k1: {
-    iv: Buffer,
-    cipherKey: Buffer,
-    macKey: Buffer
-  },
-  k2: {
-    iv: Buffer,
-    cipherKey: Buffer,
-    macKey: Buffer
-  }
-}
-```
-### `marshalPublicKey(key[, type])`
-
-- `key: crypto.rsa.RsaPublicKey`
-- `type: String`, only `'RSA'` is currently supported
-
-Converts a public key object into a protobuf serialized public key.
-
-### `unmarshalPublicKey(buf)`
-
-- `buf: Buffer`
-
-Converts a protobuf serialized public key into its  representative object.
-
-### `marshalPrivateKey(key[, type])`
-
-- `key: crypto.rsa.RsaPrivateKey`
-- `type: String`, only `'RSA'` is currently supported
-
-Converts a private key object into a protobuf serialized private key.
-
-### `unmarshalPrivateKey(buf)`
-
-- `buf: Buffer`
-
-Converts a protobuf serialized private key into its  representative object.
+See [API.md](API.md)
 
 ## Contribute
 
diff --git a/src/index.js b/src/index.js
index 7a56950..4bbe6f7 100644
--- a/src/index.js
+++ b/src/index.js
@@ -6,7 +6,6 @@ const c = require('./crypto')
 
 exports.hmac = c.hmac
 exports.aes = c.aes
-exports.rsa = c.rsa
 exports.webcrypto = c.webcrypto
 
 const keys = exports.keys = require('./keys')