add some documentation

1 files changed, 44 insertions, 1 deletions

diff --git a/README.md b/README.md
index 9c5dbe0..b2ab32b 100644
--- a/README.md
+++ b/README.md
@@ -1,4 +1,47 @@
 nthash
 ======
 
-Generate NT Hash
\ No newline at end of file
+**Generate NT Hash**
+
+The NT hash is used by Microsoft and others for authentication. This
+program `nthash` converts the standard input to UTF16 (little endian)
+and applies the MD4 hash algorithm. This resulting 32 byte string is
+printed to standard out.
+
+Requirements
+------------
+
+To compile and run `ntash` you need:
+
+* [nettle](http://www.lysator.liu.se/~nisse/nettle/)
+* [markdown](http://daringfireball.net/projects/markdown/) (HTML documentation)
+
+Additionally it is expected to have `make` and `pkg-config` around to
+successfully compile.
+
+Some systems may require additional development packages for the libraries.
+Look for `nettle-dev` or similar.
+
+Build and install
+-----------------
+
+Building and installing is very easy. Just run:
+
+> make
+
+followed by:
+
+> make install
+
+This will place an executable at `/usr/bin/nthash`.
+
+Usage
+-----
+
+Just feed `nthash` with the password on standard input. Please not that
+`nthash` does not strip new lines from input. You may want to use `echo`
+with option `-n`:
+
+> echo -n test | nthash  
+> 0cb6948805f797bf2a82807973b89537
+