rng

README.md

@@ -4,9 +4,6 @@ U2F Zero
 ========
 
 
-
-
-
 Overview
 =======
 
@@ -86,6 +83,26 @@ U2F layer:
 * u2f.h
 * u2f-atecc.c   // device specific implementation
 
+## Random number generation
+
+U2F Zero has a hardware true random number generator (TRNG).  It's used internally
+for key generating and signing but it's also exposed to the user for other use cases because
+a good source of entropy can be useful.
+
+Generate random numbers from the device:
+
+```python
+cd tools/u2f_zero_client
+./client.py rng     # output randomness at about 1400 bytes/s
+```
+
+Update the seed with user supplied data:
+
+```python
+cd tools/u2f_zero_client
+cat /dev/random | ./client.py seed     # update seed at about 410 bytes/s
+```
+
 ## Build a U2F Zero token yourself
 
 What's the point of an open source project if you can't build it yourself?
@@ -139,8 +156,8 @@ First open "app.h" and uncomment "ATECC_SETUP_DEVICE".  Now build and program th
 Now to check the device works, lock it, and get the public key used for attestation.
 
 ```bash
-cd tools/hid_config
+cd tools/u2f_zero_client
-./config.py pubkey.hex
+./client.py configure pubkey.hex
 ```
 
 The ECC public key X,Y values will be stored in hex in pubkey.hex if setup is successful.