Ed25519
A fast, modern public-key signature scheme used to sign and verify data — the keypair behind an agent's ability to prove control of its identity.
Ed25519 is a public-key signature algorithm based on the Edwards form of Curve25519. It's widely used because it's fast, produces short signatures, and has strong security with sensible defaults — you'll find it in SSH, TLS, and identity systems.
For an AI agent, an Ed25519 keypair is what lets it sign requests and prove it controls its identity. The public key is published in the agent's DID document; the private key stays with the agent.
Sign and verify
The agent holds a private key and signs a message with it. Anyone with the public key — published in the DID document — can verify the signature came from the holder of the private key and that the message wasn't altered.
This is the mechanism behind 'prove who you are' for agents: a signature over a challenge that a verifier can check.
Why Ed25519 specifically
It's quick to sign and verify, the keys and signatures are compact, and it avoids several footguns that older schemes have. That combination makes it a practical default for agent identity at scale.
FAQ
Where is the agent's private key kept?
With the agent's identity in Mailgent; the matching public key is published in its DID document for verification.
Can signatures be verified by anyone?
Yes. Anyone who resolves the agent's DID document gets the public key needed to verify a signature.
Give your agent an inbox.
A real email address, a vault, 2FA, and an identity in one API call.