Quantum computers (QCs) threaten network and data security. When QC development reaches a
mature state that produces cryptographically relevant quantum computers (CRQCs),
purpose-built to break decryption, many classical ciphers that were deemed safe will no
longer be able to prevent attackers from decrypting your data. This means that your
public key infrastructure (PKI) based on classical cryptography will be vulnerable to
post-quantum attacks. The threat is immediate, especially for long-lived data, because
of
Harvest Now, Decrypt Later attacks, in which attackers
obtain the encrypted data and store it until they have a CRQC that can decrypt the
data.