EdDSA is the newest major signing algorithm supported by the JWT specification.

It is based on Edwards-curve Digital Signature Algorithm, most commonly using the Ed25519 elliptic curve.

In recent years, EdDSA has become increasingly popular because it combines:

• Strong security
• Excellent performance
• Small keys
• Small signatures
• Simpler implementation than traditional ECDSA

Many modern security libraries now recommend Ed25519 as the default choice for new applications.

What Does EdDSA Mean?

EdDSA stands for Edwards-curve Digital Signature Algorithm.

For JWTs, EdDSA almost always refers to:

Ed25519

Although other curves exist (such as Ed448), Ed25519 is by far the most common implementation.

Unlike RS256 or ES256, the JWT header usually looks like this:

{
    "alg":"EdDSA",
    "typ":"JWT"
}

Notice that the header does not specify the curve.

The key itself determines whether Ed25519 or another Edwards curve is being used.