Also mentioned
RSARSARivest, Shamir and AdlemanA widely used public-key algorithm for encryption and digital signatures whose security relies on the difficulty of factoring large numbers.Read the full entry (new tab), ECCECCelliptic curve cryptographyElliptic curve cryptography: the family of public-key algorithms whose security rests on the difficulty of the elliptic curve discrete logarithm problem.Read the full entry (new tab), ECDHECDHElliptic Curve Diffie-HellmanElliptic Curve Diffie-Hellman, a key-exchange method using elliptic-curve mathematics to establish a shared secret with smaller keys than classical Diffie-Hellman.Read the full entry (new tab), ECDSAECDSAElliptic Curve Digital Signature AlgorithmElliptic Curve Digital Signature Algorithm, a widely deployed signature scheme based on elliptic-curve cryptography, offering strong security with compact keys.Read the full entry (new tab), ML-KEMML-KEMModule-Lattice-based Key Encapsulation MechanismModule-Lattice-Based Key-Encapsulation Mechanism, the NIST-standardized post-quantum KEM derived from CRYSTALS-Kyber and specified in FIPS 203.Read the full entry (new tab), ML-DSAML-DSAModule-Lattice-based Digital Signature AlgorithmModule-Lattice-Based Digital Signature Algorithm, the NIST-standardized post-quantum signature scheme derived from CRYSTALS-Dilithium and specified in FIPS 204.Read the full entry (new tab), SLH-DSASLH-DSAStateless Hash-based Digital Signature AlgorithmStateless Hash-Based Digital Signature Algorithm, the NIST-standardized signature scheme derived from SPHINCS+ and specified in FIPS 205.Read the full entry (new tab), KEMKEMkey encapsulation mechanismA public-key mechanism for securely establishing a shared secret key: the sender encapsulates a random secret to the recipient's public key, and the recipient decapsulates it with their private key.Read the full entry (new tab), TLSTLSTransport Layer SecurityTransport Layer Security, the protocol that encrypts and authenticates most internet traffic, including HTTPS. It uses key exchange, certificates, and symmetric encryption to protect a session.Read the full entry (new tab), FIPSFIPSFederal Information Processing StandardFederal Information Processing Standards, publicly announced standards developed by NIST for use in U.S. government computer systems, including cryptographic algorithms and modules.Read the full entry (new tab), NISTNISTNational Institute of Standards and TechnologyThe U.S. National Institute of Standards and Technology, the agency that develops and publishes cryptographic standards, including the FIPS series and post-quantum algorithms.Read the full entry (new tab) are defined in the glossary.
What is new
Four explainers covering RSA, elliptic curve, ML-KEM and ML-DSA. Two tools that generate real keys and run real encryption and signing, entirely in the browser. Sixteen topic archives so the twenty-four guides can be browsed by subject rather than only by task.
Most post-quantum writing, including some of ours, starts one step past the beginning. It assumes you already know what a key exchange is, that RSA and elliptic curve are different things, and that a signature is not encryption. Plenty of people making migration decisions do not, and there is no reason they should.
So we wrote the step before. Four guides, each explaining one algorithm in plain language, and two tools that let you make a real key and watch what it does.
The four explainers
- What is RSA? - why multiplying two primes protects anything, what a 2048-bit key actually measures, and why it is the algorithm a quantum computer breaks first.
- What is elliptic curve cryptography? - the difference between ECDH and ECDSA, which curve to pick, and why ECC falls before RSA rather than after it.
- What is ML-KEM? - what encapsulation means, and why the replacement for RSA key exchange never touches your message.
- What is ML-DSA? - what a signature proves, and where signatures fifty times larger actually hurt.
Each one ends at a command line. The browser shows you the shape of a key; your own machine is where you make one that protects something.
Two tools that run in your tab
The key generator makes real RSA, elliptic curve, ML-KEM and ML-DSA key pairs, either at random or derived from a seed phrase you choose. The encrypt and sign playground runs encryption, decryption, signing and verification against a message you type.
Neither has a network request in it. Your private key is never sent to us because it is never sent anywhere. That is also why neither is where a production key should come from, which the tools say plainly before you use them. For that, and for finding the keys you already have, the command-line tools are the serious end of the shelf.
The thing the playground exists to show
Encrypt something with ML-KEM and you get back two separate outputs: an encapsulated key of 1,088 bytes and your actual message ciphertext. Do the same with RSA and there is no encapsulated key at all. ML-KEM does not encrypt your message, it agrees a shared secret and a symmetric cipher does the work. That single misunderstanding causes more bad migration plans than any other.
Both ways of generating a key, because the difference is the lesson
The generator offers random and seed-derived keys side by side. A random key is one nothing can reproduce, so losing it means losing it. A seed-derived key comes back every time from the same phrase, which is how a wallet turns twelve words into keys, and which also means whoever knows the phrase holds the key.
RSA cannot do the second one, and the tool says why on the spot rather than hiding the option: generating an RSA key is a search for large primes, not a derivation, so there is no short path from a phrase to a key pair.
The guides are now browsable by topic
Twenty-four guides were grouped only by what you are trying to do: learn, audit, migrate, or certify. That is the right primary axis and it is useless if what you want is everything about keys. Every guide now carries topic tags, and each topic is a real page rather than a filter that exists only while you are looking at it.
- Keys - nine guides, from what RSA is to choosing between ML-DSA and SLH-DSA.
- Migration - twelve guides on sequencing the move.
- TLS and hybrid - what the deployed internet is actually doing.
- Inventory - finding the cryptography you already have, which is where every migration starts.
- Compliance and deadlines - the mandates and their dates.
The full set is at the guides hub, with a rail down the side for both axes.
Why we built it this way
The honest reason is that abstract explanations of key sizes do not land. Telling someone an ML-KEM-768 public key is 1,184 bytes against X25519's 32 is a fact they will forget. Generating both in the same minute and watching the second box dwarf the first is a thing they will remember when a protocol designer tells them the migration is a drop-in swap.
The tools are built on @noble/post-quantum, the pure-JavaScript library we audited twice and published eighteen findings against. Using the library we reviewed, rather than one we have not, seemed like the least we could do.
All of it is free, none of it needs an account, and none of it sends anything to us. Where a whole team has to get through this rather than one curious person, that is what training is for.
References
- FIPS 203: Module-Lattice-Based KEM (csrc.nist.gov) - the ML-KEM standard.
- FIPS 204: Module-Lattice-Based Digital Signature Standard (csrc.nist.gov) - the ML-DSA standard.
- RFC 8017: PKCS #1 v2.2 (rfc-editor.org) - RSA as actually implemented.
- FIPS 186-5: Digital Signature Standard (csrc.nist.gov) - ECDSA and the NIST curves.