For example, newer and faster algorithms have already been developed, such as the JVG algorithm, that require less quantum computational power (qubits) to factor large prime numbers, on which some legacy cryptosystems such as RSA are based.
Google argues that advances in quantum computing, including hardware development, quantum error correction, and quantum factoring resource estimates, are bringing forward the time legacy cryptographic algorithms will become vulnerable to quantum computing, a phenomenon known as Q-Day.
“Google’s accelerated 2029 deadline reflects a shift from trying to predict Q-day to managing pre-Q-day risk,” says Mark Pecen, chair of technical committee on quantum technologies at the European Telecommunications Standards Institute (ETSI). “The real concern isn’t when quantum computers arrive; it’s that adversaries are already collecting encrypted data today to decrypt later.”
