Ed25519 Applet

Live demo: https://cyphr.me/ed25519_applet/ed.html

This tool can run locally and offline

git clone this project to a local directory.

git clone https://github.com/Cyphrme/ed25519_applet.git

Then, in your web browser, use file:// to load ed.html

file:///pathToDirectory/ed.html

Signing and verification tool for Ed25519

• Sign a message.
• Verify a signature.
• Generate a public key from seed.
• Generate a new random public/private key pair and seed.

Supported formats:

Messages: Base64, Hex, and Text (Bytes). Keys: Base64 and Hex.

Naming Differences in Implementations

Many libraries, including this tool, refer to what the RFC calls "private key" as the "seed" (like Go ). The 32 byte seed is used to generate the private component "secret scalar s", the public key, and the "prefix" (nounce).

The "actual" private component (secret scalar s as named by the RFC (Section 5.1.5.3)) is typically regenerated from seed on signing, although it is possible to use secret scalar s and prefix to sign without the seed. The public component is computed from "secret scalar s", but prefix is generated from seed and is used for signing. NaCL used to return the private key as secret scalar s concatenated with prefix . Instead of requiring secret scalar s and prefix for signing, most libraries required seed and regenerate both secret scalar s and prefix from seed, and optionally cache the public key.

What some libraries call the "private key" (64 bytes) is the seed (32 bytes) concatenated with the public key (32 bytes). (Caching the public key precludes relatively slow regeneration when signing.)

TODO

Ed25519ph

paulmillr/noble-ed25519#63

Paul's Noble library currently only supports "PureEdDSA" and does not support Ed25519ph ("pre-hashed"). We are waiting for it to be supported before we can implement it.

Generate from seed "secret scalar s" and permit input from sss || prefix

It would be nice to output "secret scalar s" || "prefix" and accept it as input as well. See paulmillr/noble-ed25519#64. It would require additional code to Noble since sss || prefix is not a possible input, assuming seed is not given.

We might never do this if there's no use for it among all modern tools.

Dist

noble-ed25519.js is taken directly from Noble and may be used in other applications. See also join.js.

Other ed25519 resources:

• https://ed25519.cr.yp.to/
• https://en.wikipedia.org/wiki/EdDSA
• https://ianix.com/pub/ed25519-deployment.html

Attribution

Implemented using noble/ed25519: https://github.com/paulmillr/noble-ed25519

"Cyphr.me" is a trademark of Cypherpunk, LLC. The Cyphr.me logo is all rights reserved Cypherpunk, LLC and may not be used without permission.

Keywords

Ed25519 test page, Ed25519 online tool.