home.md

 # API Document
-1. Create a new account
+## Create a new account
 
 * URL: `account/new`
 
@@ -18,7 +18,7 @@
 | serial | char(32) | the serial of the new account |
 | username | string | the username of the new account |
 
-2. Authenticate (Install) a new machine
+## Authenticate (Install) a new machine
 
 * URL: `machine/new`
 
@@ -38,10 +38,50 @@
 | pri_key | base64 string | RSA private key |
 | machine_id | int | ID of the machine |
 
-3. Revoke the authentication of a machine
+## Revoke the authentication of a machine
+
+* URL: `machine/revoke`
+
+* Request
 
 | Parameter | Type | Description |
 | ----- | ----- | ----- |
 | username | string | username |
 | password | string | password |
 | machine_id | int | ID of the machine to revoke |
+
+## Authenticate an existed machine
+
+* URL: `machine/auth`
+
+#### Step 0
+
+* Request
+
+| Parameter | Type | Description |
+| ----- | ----- | ----- |
+| serial | string | serial of user |
+| pub_key | base64 string | public key on the machine |
+
+* Response
+
+| Parameter | Type | Description |
+| ----- | ----- | ----- |
+| encrypted | string | encrypted text for the client to decrypt |
+| auth_id | int | authentication sequence ID |
+
+#### Step 1
+
+* Request
+
+| Parameter | Type | Description |
+| ----- | ----- | ----- |
+| decrypted | string | decrypted text from the client |
+| auth_id | int | authentication sequence ID |
+
+* Response
+
+| Parameter | Type | Description |
+| ----- | ----- | ----- |
+| nfc_pass | base64 string | password of the NFC |
+| auth_id | int | authentication sequence ID |