You're absolutely right, this POC took me 15 minutes longer than I expected. 🤣

from ecdsa import SigningKey, VerifyingKey

import smtplib

from email.mime.text import MIMEText

import lnd_grpc

import imaplib

import email

# Initialize Lightning Network client (Assumes LND is running)

lnd_client = lnd_grpc.Client()

# Generate ECDSA keys for sender and receiver

sk = SigningKey.generate() # Sender's private key

vk = sk.get_verifying_key() # Sender's public key

# Step 1: Initiate Lightning Network Payment

payment_request = lnd_client.add_invoice(value=10)

pending_payment = lnd_client.send_payment(payment_request)

# Step 2: Generate Cryptographic Signature

email_content = "Hello, this is a test email."

signature = sk.sign(email_content.encode())

# Step 3: Send Email with Signature

server = smtplib.SMTP('smtp.example.com', 587)

server.starttls()

server.login("sender@example.com", "password")

msg = MIMEText(email_content)

msg['Subject'] = 'Test Email'

msg['From'] = 'sender@example.com'

msg['To'] = 'receiver@example.com'

msg['X-Crypto-Signature'] = signature.hex()

server.send_message(msg)

server.quit()

# Receiver's Email Verification

mail = imaplib.IMAP4_SSL('imap.example.com')

mail.login('receiver@example.com', 'password')

mail.select('inbox')

status, messages = mail.search(None, 'ALL')

email_ids = messages[0].split()

latest_email_id = email_ids[-1]

status, msg_data = mail.fetch(latest_email_id, '(RFC822)')

raw_email = msg_data[0][1]

received_email = email.message_from_bytes(raw_email)

received_signature = received_email['X-Crypto-Signature']

received_content = received_email.get_payload()

# Verify the signature

if vk.verify(bytes.fromhex(received_signature), received_content.encode()):

print("Email is verified.")

# Uncomment to settle the Lightning Network payment

# lnd_client.settle_payment(pending_payment)

else:

print("Email verification failed.")

Now run and manage the code. Don’t forget liquidity and uptime. And you should get a watchtower too.