Quantum risk is often treated as tomorrow's encryption problem. It is already today's identity planning problem. A cryptographically relevant quantum computer could threaten widely used public-key algorithms that support authentication, digital signatures, key establishment, certificates, and federation.
Adversaries do not need to wait for that computer to exist. In harvest-now-decrypt-later attacks, they can collect protected information today and hold it until future capabilities make it readable. For agencies responsible for long-lived, sensitive information, the threat clock is already running.
NIST finalized its first three PQC standards in 2024: FIPS 203 for ML-KEM key establishment and FIPS 204 and FIPS 205 for digital signatures.2 OMB Memorandum M-26-15 directs federal civilian agencies to plan and execute a risk-based migration, prioritizing high-impact systems, High Value Assets, highly sensitive data, and systems that rely on vulnerable asymmetric cryptography.3
For SAML environments, the challenge exists at multiple layers:
The TLS connection that transports a SAML message may depend on quantum-vulnerable key establishment.
The SAML assertion may be signed with RSA or ECDSA through XML Signature.
The assertion or attributes may use XML Encryption with classical cryptographic dependencies.
Certificates, keys, libraries, identity providers, service providers, and application code may each have separate upgrade paths.
Quantum readiness is not a cipher-suite update. It is an end-to-end identity modernization effort. Agencies need a cryptographic inventory and a migration plan that accounts for the entire transaction, not just the first encrypted connection.