Why use 2048-bit DKIM keys instead of 1024-bit?

A 2048 bit key provides exponentially stronger cryptographic security. The "why" comes down to the computational effort required to crack the key.

A 1024 bit key is now considered vulnerable to being "factored" (broken) by well-resourced attackers. If an attacker compromises your private key, they can sign fraudulent messages as you, pass authentication checks, and perfectly impersonate your brand to commit fraud.

Using a 2048 bit key makes this attack computationally infeasible. It is the difference between locking your ship's safe with a simple padlock versus a bank vault door. It ensures your digital signature—your "wax seal"—cannot be forged.