What Are Ed25519 DKIM Signtaures?

Ed25519-SHA256 DKIM signatures are a modern, secure, and efficient way of authenticating email. Based on the Ed25519 elliptic curve signature algorithm (EdDSA) and defined in RFC 8463, these signatures provide strong cryptographic protection with significantly smaller key sizes than traditional RSA-based DKIM.

Unlike 2048-bit or 4096-bit RSA keys, Ed25519 uses compact 256-bit keys while delivering comparable or stronger security.

Key Benefits

Stronger Security: Delivers high cryptographic strength with modern elliptic curve design.

Smaller DNS Footprint: The compact public key fits easily within a single DNS TXT record, simplifying DNS management and reducing fragmentation risks.

Faster Performance: Enables quicker signing and verification, improving efficiency for high-volume mail systems.

While adoption across major email providers continues to grow, Ed25519 is commonly deployed alongside RSA in a dual-signing configuration to ensure broad compatibility.

You can use our free DKIM Record Lookup to test your current DKIM setup and see if changes are needed.