dkimpy

import os from dkimpy.dkim import DKIM, verify, DKIMException # In a real application, load your actual private key and use your domain/selector. # Example key generation (using openssl): # openssl genrsa -out dkim.private 1024 # openssl rsa -in dkim.private -pubout -out dkim.public # Then load: `with open('dkim.private', 'rb') as f: private_key = f.read()` private_key = os.environ.get('DKIM_PRIVATE_KEY', b"") # Should be bytes domain = os.environ.get('DKIM_DOMAIN', 'example.com') selector = os.environ.get('DKIM_SELECTOR', 's1') # Sample email content (bytes) - DKIMpy works with byte strings email_message_bytes = b"""From: sender@example.com\r\nTo: recipient@example.com\r\nSubject: Test DKIM Signature\r\n\r\nThis is the body of the email.\r\n""" # --- 1. Sign an email --- print("--- Signing an Email ---") if not private_key: print("Warning: DKIM_PRIVATE_KEY environment variable not set. Signing will likely fail.") print("Please provide a valid private key for real signing.") try: # Initialize the DKIM signer signer = DKIM( message=email_message_bytes, selector=selector.encode(), # Selector must be bytes domain=domain.encode(), # Domain must be bytes privkey=private_key ) # Sign the message signed_email_bytes = signer.sign() print("Email signed successfully. First 500 bytes of signed email:") print(signed_email_bytes[:500].decode(errors='ignore')) print("...") except DKIMException as e: print(f"Error signing email: {e}") except Exception as e: print(f"An unexpected error occurred during signing: {e}") # --- 2. Verify a received email --- # For actual verification, the signed email needs to be received, and # dkimpy will perform DNS lookups for the public key (TXT record). print("\n--- Verification Example (requires real signed email and DNS) ---") received_signed_email_bytes = signed_email_bytes # Use the just-signed email for demonstration try: # The `verify` function is a module-level function # It returns a list of (dkim_domain, dkim_selector, ...) tuples for each valid signature. result = verify(received_signed_email_bytes) if result: print(f"Verification successful. Found {len(result)} valid DKIM signatures.") # print(f"Result details: {result}") # Uncomment for verbose output else: print("Verification failed or no valid DKIM-Signature found.") except DKIMException as e: print(f"Verification encountered an error: {e}") except Exception as e: print(f"An unexpected error occurred during verification: {e}")