The goal of this website is to help people engage with progress in quantum computing by showing what it means for digital security.
If a large quantum computer were built – what would you do with it?
This site offers one possibility: you can use it to uncover time capsules — deeply personal messages sealed away long ago, now unlocked by the power of a quantum mechanics.
When you submit a message, it is encrypted using RSA — a form of cryptography based on the difficulty of factoring large numbers.
Encryption transforms your message into a scrambled form that cannot be read without a private key. For example:
After encryption, the private key is immediately deleted. This means no one — not even the server — can decrypt the message today. The encrypted message is stored in the database as a digital time capsule.
The message will remain unreadable unless a future quantum computer is powerful enough to break RSA encryption by factoring the underlying key.
RSA encryption is considered secure today because factoring large numbers is extremely difficult for classical computers. But quantum computers will change that. A future machine running Shor’s algorithm could efficiently break RSA by factoring its encryption key.
It’s estimated that a machine with around 15,000 qubits would be needed to break RSA-2048, though this number could decrease with algorithmic or hardware improvements.
Post-quantum cryptography refers to cryptographic algorithms designed to be secure against the potential threats posed by quantum computers. As quantum technology advances, traditional encryption methods like RSA and ECC could become vulnerable. To address this, new algorithms are being developed to resist quantum attacks.
Examples of these quantum-resistant algorithms include:
These algorithms have been selected by the National Institute of Standards and Technology (NIST) as part of their ongoing efforts to standardize quantum-resistant cryptographic methods. For an in-depth overview, see NIST’s official announcement.