What is post-quantum cryptography, and why should businesses care now?
Almost everything you do online, from logging in to a banking app to sending a WhatsApp message, is protected by public-key cryptography. The most common kinds, RSA and elliptic-curve cryptography (ECC), rely on maths problems that ordinary computers would need thousands of years to solve.
A large enough quantum computer could solve them much faster, using a method called Shor's algorithm. Such a machine does not exist yet, and nobody knows exactly when one will. But the risk is already real today, for one simple reason.
"Harvest now, decrypt later"
An attacker does not need a quantum computer today to cause harm later. They can copy encrypted traffic or stolen databases now, store them, and wait until they can decrypt them. If your data must stay secret for 5, 10 or 20 years, such as medical records, contracts, identity documents, trade secrets or government data, it may already be at risk.
A useful rule of thumb: if how long your data must stay secret plus how long it takes you to migrate is longer than the time until a capable quantum computer exists, you are already late.
What is post-quantum cryptography?
Post-quantum cryptography (PQC) means new algorithms that run on today's normal computers and phones, but are designed to resist attacks from both classical and quantum computers. No special quantum hardware is needed to use them.
In August 2024, the US National Institute of Standards and Technology (NIST) published the first three PQC standards, after an open, multi-year international competition:
| Standard | Algorithm | Used for |
|---|---|---|
| FIPS 203 | ML-KEM | Key exchange: agreeing on a secret key, for example in HTTPS/TLS |
| FIPS 204 | ML-DSA | Digital signatures: certificates, software updates, documents |
| FIPS 205 | SLH-DSA | Hash-based digital signatures, a conservative backup option |
In March 2025, NIST also selected HQC as a backup key-exchange algorithm based on different mathematics, with its standard still in development.
Symmetric encryption such as AES and hash functions such as SHA-256 are much less affected. Using AES-256 is generally considered sufficient.
The deadlines are now official
In October 2026, NIST finalized its transition plan (NIST IR 8547). It says RSA and ECC will be deprecated after 2030 and disallowed after 2035 for systems that follow NIST rules. "Deprecated" means still allowed, but the organization must accept the risk. Many governments, regulators and large companies use NIST rules as a reference, so these dates are likely to reach their suppliers and partners too, including in Indonesia.
Meanwhile, the change is already happening quietly: major web browsers and cloud providers have started using hybrid key exchange, which combines a classical algorithm with ML-KEM, so the connection stays safe as long as either one holds.
What a business can do now
- Make an inventory. List where you use cryptography: websites, APIs, VPNs, databases, backups, certificates, code signing, and third-party services.
- Find your long-lived secrets. Rank data by how long it must stay confidential. Start with that.
- Ask your vendors. Find out when your cloud, hosting, payment, VPN and software providers will support PQC.
- Build crypto-agility. Avoid hard-coding algorithms, so you can switch them through configuration and updates later.
- Start with hybrid TLS. Upgrading servers and libraries to support hybrid ML-KEM key exchange protects data in transit against "harvest now, decrypt later".
- Plan your certificates. Moving signatures and certificates (PKI) takes the longest, so plan it early.
Migration is not a single switch. For most organizations it is a multi-year project, which is exactly why starting with an inventory and a roadmap now is cheaper than rushing near 2030.
Want help working out where you stand? Book a PQC consultation with Binjesoft.
Further reading: NIST Post-Quantum Cryptography project · Cloud Security Alliance: NIST IR 8547 final