With the rise of cryptographically relevant quantum computers on the horizon, companies need to start planning for quantum readiness. The relevant threats and a rough timeline of when they become real must be known. Notably, even encrypted data transmitted today may be at risk if it is stored and decrypted later, once a quantum computer becomes available. A first step on the journey toward quantum-safety is to build a cryptographic inventory and rate data assets according to risks imposed by quantum computers. Among other measures, companies must aim at cryptographic agility—in their networks, their software, and their supply chain.