update readme

README.md

@@ -1,32 +1,53 @@
 # go-xmlsec
 
-[![Build Status](https://travis-ci.org/crewjam/go-xmlsec.svg?branch=master)](https://travis-ci.org/crewjam/go-xmlsec)
+[![](https://godoc.org/github.com/crewjam/go-xmlsec?status.png)](http://godoc.org/github.com/crewjam/go-xmlsec) [![Build Status](https://travis-ci.org/crewjam/go-xmlsec.svg?branch=master)](https://travis-ci.org/crewjam/go-xmlsec)
 
-[![](https://godoc.org/github.com/crewjam/go-xmlsec?status.png)](http://godoc.org/github.com/crewjam/go-xmlsec)
+A partial wrapper for [xmlsec](https://www.aleksey.com/xmlsec). 
 
-A (partial) wrapper for [xmlsec](https://www.aleksey.com/xmlsec).
+As seems to be the case for many things in the XMLish world, the xmldsig and xmlenc standards are more complex that may be nessesary. This library is as general as I could reasonably make it with an eye towards supporting the parts of the standards that are needed to support a SAML implementation. If there are missing bits you feel you need, please raise an issue or submit a pull request. 
 
-# Signing (xmldsig)
+# Examples
 
-## Signing Example
+## Signing
 
     key, _ := ioutil.ReadFile("saml.key")
     doc, _ := ioutil.ReadAll(os.Stdin)
-    signedDoc, err := xmldsig.Sign(key, doc, xmldsig.Options{})
+    signedDoc, err := Sign(key, doc, SignatureOptions{})
     os.Stdout.Write(signedDoc)
 
-## Verifying Example
+## Verifying
 
     key, _ := ioutil.ReadFile("saml.crt")
     doc, _ := ioutil.ReadAll(os.Stdin)
-    err := xmldsig.Verify(key, doc, xmldsig.Options{})
+    err := xmldsig.Verify(key, doc, SignatureOptions{})
     if err == xmldsig.ErrVerificationFailed {
       os.Exit(1)
     }
 
-## Decrypting Example
+## Decrypting
 
     key, _ := ioutil.ReadFile("saml.key")
     doc, _ := ioutil.ReadAll(os.Stdin)
-    plaintextDoc, err := xmlenc.Decrypt(key, doc)
+    plaintextDoc, err := Decrypt(key, doc)
     os.Stdout.Write(plaintextDoc)
+
+## Encrypting
+
+    key, _ := ioutil.ReadFile("saml.crt")
+    doc, _ := ioutil.ReadAll(os.Stdin)
+    encryptedDoc, err := Encrypt(key, doc, EncryptOptions{})
+    os.Stdout.Write(encryptedDoc)
+
+# Install
+
+This package uses cgo to wrap libxmlsec. As such, you'll need libxmlsec headers and a C compiler to make it work. On linux, this might look like:
+
+    $ apt-get install libxml2-dev libxmlsec1-dev
+    $ go get github.com/crewjam/go-xmlsec
+
+On Mac with homebrew, this might look like:
+
+    $ brew install libxmlsec1 libxml2
+    $ go get github.com/crewjam/go-xmlsec
+
+