merge readme from upstream

README.md

@@ -1,31 +1,30 @@
 # Key Manager
 
-Manage keys for FISCO BCOS.
+Manage data encryption keys for FISCO BCOS nodes.**The version only supports** [FISCO BCOS 2.0](https://fisco-bcos-documentation.readthedocs.io/zh_CN/release-2.0/docs/introduction.html).
 
 ## Description
 
-In FISCO BCOS consortium chain framework, each organization has their own key manager. Organization use key manager to manage their keys. Key manager is deployed in organization's internal network. **The version only supports** [FISCO BCOS 2.0](https://fisco-bcos-documentation.readthedocs.io/zh_CN/release-2.0/docs/introduction.html).
+In FISCO BCOS, each agency should run its own key manager service. The key manager is deployed in the internal network to manage its data encryption keys.
 
-
-In **disk encryption**. This shows how key manager manages data key for nodes. 
+In **disk encryption**. The following figure shows how the key manager manages encryption data keys. 
 
 ![](docs/imgs/framework.png)
 
-Each node has their own ``` dataKey``` and use ``` dataKey``` to communicate with its encrypted space. Node does not manage its ``` dataKey```. It only has its ``` cipherDataKey```. ``` cipherDatakey``` is the cipher of ``` datakey ```encrypted by ``` superKey```.  When node is booting, it sends ``` cipherDataKey``` to key manager, and key manager decrypts the ``` cipherDataKey```  using ``` superKey ``` and return ``` dataKey``` to node. Node manage ``` dataKey``` in memory and drop it after shutting down.
+Each node has their own ``` dataKey``` and use ``` dataKey``` to communicate with its encrypted space. A node does not manage its ``` dataKey```. It only has its ``` cipherDataKey```. ``` cipherDatakey``` is the ciphertext of ``` datakey ```encrypted by ``` superKey```.  When the node is booting, it sends ``` cipherDataKey``` to key manager, and key manager decrypts the ``` cipherDataKey```  using ``` superKey ``` and return ``` dataKey``` to the node. The node stores ``` dataKey``` in memory and drop it after the node is shut down.
 
 ## How to use
 
 ### Clone
 
-``` shell
+```shell
 git clone https://github.com/FISCO-BCOS/key-manager.git
 ```
 
 ### Install package
 
 Install
 
-``` shell
+```shell
 # In Centos
 sudo yum install procps-ng-devel
 # In ubuntu
@@ -34,7 +33,7 @@ sudo apt-get install libprocps-dev
 
 ### Build
 
-``` shell
+```shell
 cd key-manager
 mkdir build
 cd build
@@ -53,15 +52,15 @@ make
 
 ### Start
 
-``` shell
-./key-manager 31443 123xyz # key-manager <port> <superkey>
+```shell
+./key-manager 31443 123xyz # key-manager <port> <superkeyString>
 ```
 
 ### Check
 
 Print info when successfully started.
 
-``` log
+```log
 [1545471609499] [TRACE] key-manager stared. Port: 31443
 ```