update README

README.md

@@ -1,4 +1,4 @@
-# ZoKrates
+# Zokrates
 
 [![Join the chat at https://gitter.im/ZoKrates/Lobby](https://badges.gitter.im/ZoKrates/Lobby.svg)](https://gitter.im/ZoKrates/Lobby?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
 
@@ -6,16 +6,25 @@ Zokrates is a toolbox for zkSNARKs on Ethereum.
 
 _This is a proof-of-concept implementation. It has not been tested for production._
 
-## Using ZoKrates
+# Motivation
 
-ZoKrates provides a command line interface.
-To see an overview of the available subcommands, run
+Ethereum runs computations on all nodes of the network, resulting in high costs, limits in complexity, and low privacy.
+SNARKs have been enabling to only verify computations on-chain for a fraction of the cost of running them, but are hard to grasp and work with.
+
+Zokrates bridges this gap. It helps you create offchain programs and link them to the Ethereum blockchain, expanding the possibilities for your Dapp.
+
+# Installation
+
+Using Docker is currently the recommended way to get started with Zokrates.
 
 ```
-./zokrates
+git clone https://github.com/JacobEberhardt/ZoKrates
+cd ZoKrates
+docker build -t zokrates .
+docker run -ti zokrates /bin/bash
+cd ZoKrates/target/release
 ```
-
-### Example
+# Example
 
 To execute the program, perform the setup for the program, generate a proof
 ```
@@ -31,32 +40,73 @@ with `add(1, 2, 3)`, call
 ./zokrates export-verifier
 ```
 
-## Building
+# API reference
 
-Currently needs to be build with nightly Rust.
+Zokrates provides a command line interface.
+You can see an overview of the available subcommands by running
 
-### Docker (Recommended)
-
-Example usage:
 ```
-docker build -t zokrates .
-docker run -ti zokrates /bin/bash
-cd ZoKrates
-./target/release/zokrates compile -i examples/add.code
+./zokrates
 ```
 
-### Without libsnark
-Build with the feature `nolibsnark`
+## `compile`
 ```
-cargo build --features nolibsnark
+./zokrates compile -i /path/to/add.code
 ```
 
-### Environment Variables
-Set the libsnark library path in `LD_LIBRARY_PATH`
+Compile a `.code` file.
+
+Creates a compiled `.code` file at `./out.code`.
+
+## `compute-witness`
 ```
-export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/local/lib
+./zokrates compute-witness -a 1 2
 ```
 
+Computes a witness for the compiled program found at `./out.code` and arguments to the program.
+A witness is a valid assignment of the variables, which include the results of the computation.
+
+Creates a witness file at `./witness`
+
+## `setup`
+```
+./zokrates setup
+```
+
+Generates a trusted setup for the compiled program found at `./out.code`.
+
+Creates a proving key and a verifying key at `./proving.key` and `./verifying.key`.
+
+## `export-verifier`
+```
+./zokrates export-verifier
+```
+
+Using the verifying key at `./verifying.key`, generates a Solidity contract enabling to verify proofs for computations of the compiled program at `./out.code`.
+
+Creates a verifier contract at `./verifier.sol`
+
+## `generate-proof`
+```
+./zokrates generate-proof
+```
+
+Using the proving key at `./proving.key`, generates a proof for a computation of the compiled program `./out.code` resulting in `./witness`.
+
+Returns the proof, for example:
+```
+A = 0x45582d7906c967b1fd1cac0aad3efefa526e4cd888b8ecb5907b46c2eb1f781, 0x8158089a63a6aafa4afc3bbfd5ebf392e5ef61d0c5faf2e2445c9112450f29c
+A_p = 0x5e4fe0bfa79a571b8918138ee5d7b3d0ad394c9bb8f7d2e1549f7e3c3bab7e9, 0x1708b5ba3d138e433406c792f679ae6902fc9f7c6131305a9a5f826dbe2d71fb
+B = [0x34f5c5b7518597452e55a69bf9171a63837a98a1c1c1870b610b2cfe79c4573, 0x18e56afd179d67960db838a8fdb128eb78d5dd2c1ffcd564f9d0dada928ed71f], [0xf160ea8d2dc33b564a45c0998309b4bf5a050cc8f6288793b7401b37d1eb1a2, 0x23ade8ba2c64300b5ff90e18641516407054a21179829252fd87f1bd61a3be34]
+B_p = 0xc88b87d45f90da42b9c455da16dad76996ef5b1e859a4f0db7dcef4f7e3b2fd, 0x20ed7c62dd8c6c47506e6db1d4837daa42ae80b931227153054539dcbf6f3778
+C = 0x2c230cbffbcb6211d2cf8f434df291a413721e3bef5ada4030d532d14b6ea504, 0x21421565f75429d0922c8cf00b68e4da23c61670e787ce6a5de14a5a86ebdcb0
+C_p = 0xce11fe724ce1ce183c15c4f5405d9607d6c769422aa9f62f4868478324a2f5, 0x1e585b35ed22ef32fd70ef960818f1514d1dd94b3517c127e782de24173c69f9
+H = 0x2306e74a1a7e318d2d3c40cbea708b0e0b91cd1548c9db6261fc2bd815740978, 0xde538e4e99b0e20e84cdbbd3bc08c37bca0af21edd67faf52bc4027a9b00f7c
+K = 0x1868436121f271e9fbf78a8f75bb4077e2d4f208891793fd5b468afc3b05c0e4, 0x1021c3ecb15c3fd7340d4eb5bf446e1ad457020e4f8b7cc82f8af64507a35fbe
+```
+
+Passed to the verifier contract, this proof can be checked.
+
 ## Testing
 
 Run normal tests with