Validates ISBN-10 and ISBN-13 book identifiers using their respective checksum algorithms. Converts ISBN-10 to ISBN-13 (adds 978 prefix and recalculates check digit) and extracts registration group, registrant, and publication codes. Accepts input with hyphens, spaces, or no separators.
Enter an ISBN to validate it and convert between ISBN-10 and ISBN-13 formats.
Generate HMAC signatures using SHA-256, SHA-512, and other algorithms.
Check password strength against security criteria and estimate crack time.
Validate credit card numbers using the Luhn algorithm.
Validate and parse International Bank Account Numbers (IBANs).
Encode text to hexadecimal or decode hex back to text.
Encrypt and decrypt text using the Caesar (ROT-N) substitution cipher.