Your emails are sent encrypted. Yet someone may already be keeping a copy, patiently waiting for the day they can read it.
That is what post-quantum cryptography (PQC) is all about: protecting the confidentiality of your data today against the quantum computers of tomorrow. For your communications, the race has begun. On your marks, get set, go!
“Harvest Now, Decrypt Later”: a threat that has already begun
This scenario has a name: “Harvest Now, Decrypt Later”. It consists of copying encrypted communications today, then quietly storing them for years.
When the time comes, all that remains is to open them. This will become possible as soon as a quantum computer can break RSA and elliptic curves, the algorithms that protect most encrypted communications today.
Q-day: a deadline with no fixed date
That day has a name too: Q-day. It could arrive around 2035. No one knows the exact date, but the real question lies elsewhere.
Will your data still need to stay secret in ten years?
Will your board meeting minutes, your bids and your HR files still need to remain secret in ten years? If the answer is yes, they are already exposed. Because a message copied today can be read tomorrow.
Post-quantum cryptography: the timeline is already set
While the date of Q-day remains uncertain, the timeline is set:
2027: ANSSI (the French National Cybersecurity Agency) will no longer certify products without post-quantum cryptography;
2030: purchases will have to cover quantum-resistant solutions;
2035: end of the migration planned by the European roadmap.
In other words, the transition is no longer a long-term project: it starts now.
The double lock: ML-KEM and X25519 combined
The good news: the answer already exists. It relies on a double lock that combines two key exchange mechanisms.
ML-KEM (FIPS 203 standard) is an algorithm designed to withstand quantum computers. X25519 is a classic elliptic-curve algorithm. Combined, they keep the key secure as long as either one holds.
? Watch our video on post-quantum cryptography (30 seconds)
With Secuserve, protection is already available
At Secuserve, this protection is not a promise for the future. It is already built into our solutions, at every stage of your communications.
Post-quantum encryption in SecuShare, MAX and My e-securemail
SecuShare, MAX and My e-securemail already use post-quantum encryption.
Secure email delivery with e-securemail
e-securemail enforces TLS 1.3, the latest version of the protocol that encrypts communications between mail servers. It also relies on DANE and MTA-STS, two mechanisms that ensure this encryption is actually applied and cannot be bypassed.
Finally, e-securemail already signs with DKIM2, the new generation of the signature that certifies the origin and integrity of an email.
Message encryption and strong authentication with optimails, Optimails SHEX and JiiMail
The optimails, Optimails SHEX and JiiMail messaging solutions offer S/MIME and OpenPGP, two standards that encrypt the content of the messages themselves. They also provide multi-factor authentication (MFA) or authentication with a YubiKey physical security key, so that only the right user can access their mailbox.
Key takeaways
With the “Harvest Now, Decrypt Later” scenario, your encrypted emails can be copied today and read later.
Q-day could arrive around 2035: data that must remain secret in ten years is already exposed.
The timeline is set: 2027 for ANSSI, 2030 for purchasing, 2035 for the end of the European migration.
The ML-KEM and X25519 double lock keeps the key secure as long as either algorithm holds.
Secuserve solutions already include these protections.
The race is on
Secuserve offers French, sovereign solutions, because your emails from 2026 must remain secret and sovereign in 2035. The race is on: shall we go together?
Get your email ready for the post-quantum era
Threat, timeline, solutions: find the essentials of post-quantum cryptography in our white paper.