Cleaning up ant_network_keys and adding some examples in README.

ant_network_keys/README.md

@@ -4,15 +4,44 @@ This folder contains the specification describing the validation of ANT network
 
 In *spec.md*, you can find the specification written after a reverse engineering process of the ANT NRF52 SoftDevice.
 
+## Testing the implementation
+
 To use the implementation, use :
 
 `
 $ make
 `
 
-Then you can run the binary and provide a key to check the validity and generate the corresponding ANT preamble:
+Then you can run the binary and provide a key as an hexadecimal stream to check the validity and generate the corresponding ANT preamble:
 
 `
 $ cd build
 $ ./key
 `
+
+For example, you can provide the ANT+ Network Key (45C372BDFB21A5B9), which should be valid and generate the preamble 0xc5a6:
+
+`
+$ ./key
+Key: 45C372BDFB21A5B9
+
+The provided key is correct, and the corresponding preamble is: 0xc5a6
+`
+
+You can also try the ANT-FS Network Key (C1635EF5B923A4A8), which should also be valid and generate the preamble 0xa33b:
+
+`
+$ ./key
+Key: 45C372BDFB21A5B9
+
+The provided key is correct, and the corresponding preamble is: 0xc5a6
+`
+
+Finally, if you try an incorrect key like 1122334455667788, it should indicate that the key is invalid and don't generate any preamble.
+
+`
+$ ./key
+Key: 1122334455667788
+
+Error: invalid key
+`

ant_network_keys/spec.md

@@ -27,5 +27,3 @@ the most significant byte is formed by combining several expressions using a or
 - the second expression takes the 3rd and the 4th bytes of the key, xor them together, and applies a mask of value 0xc0 using an and bitwise operator
 - the third expression takes the 3rd byte of the key and applies a mask of value 0x13 using an and bitwise operator
 - the fourth expression takes the 3rd, the 4th, the 5th and the 6th bytes of the key, xor them together, and applies a mask of value 0x24 using an and bitwise operator
-:w
--