Q Day refers to the anticipated future point when quantum computers become powerful enough to break widely used public-key cryptographic systems, such as RSA and ECC, which currently secure most digital communications. This event poses a significant threat to data privacy and security, as encrypted information could be decrypted by adversaries with access to quantum technology. Organizations and governments are preparing for Q Day by researching and implementing quantum-resistant cryptographic algorithms, also known as post-quantum cryptography. The exact timing of Q Day is uncertain, but its potential impact on cybersecurity is driving urgent action to safeguard sensitive data before quantum computers reach this capability.