//Let's create a digital signature!

atecc.createSignature(message); // by default, this uses the private key securely stored and loc

ked in slot 0.

// Now let's send the message to Bob.

// this will include three things:

// (1) start header ("$$") ASCII "$" = 0x24 HEX

// (2) message (32 bytes)

// (3) signature (64 bytes)

// start header

Serial1.print("$");

// message

// note, we use "Serial.write" because we are sending bytes of data (not characters)

for (int i = 0; i < sizeof(message) ; i++) Serial1.write(message[i]);

// signature

// Note, in Example4_Alice we are printing the signature we JUST created,

// and it lives inside the library as a public array called "atecc.signature"

for (int i = 0; i < sizeof(atecc.signature) ; i++) Serial1.write(atecc.signature[i]);

transmission and helps ensure that Bob hears the entire message.

One important thing to note is that when Alice sends her message and signature to Bob, she uses the

Now let's take a closer look at the important stuff in Example4_Bob.ino. Bob's sketch is actually quite similar to

// Delete this "blank" public key,

// copy/paste Alice's true unique public key from her terminal printout in Example4_Alice.

uint8_t AlicesPublicKey[64] = {

0xB4, 0x07, 0x88, 0x28, 0x8C, 0xFA, 0x71, 0xBA, 0x08, 0xE3, 0x38, 0xE0, 0x4A, 0x17, 0x68, 0xCC,

0x3E, 0xCD, 0x48, 0xA8, 0x11, 0x52, 0xDD, 0x37, 0xA1, 0xC2, 0x55, 0x75, 0x81, 0xBE, 0x4E, 0x7E,

0x78, 0x98, 0x95, 0xF6, 0x6D, 0xE7, 0x1C, 0x9A, 0x36, 0xE6, 0xB0, 0x14, 0x5D, 0x50, 0x67, 0x91,

0x7C, 0x41, 0xB8, 0x99, 0x20, 0x75, 0x3A, 0x7D, 0xA1, 0xFB, 0xF5, 0x5E, 0x8A, 0x65, 0xF5, 0x8A

};

At the top, you need to copy in Alice's public key. Bob will need this to verify any messages and signatures he

receives. Note, yours will be different than what I'm showing above.