Why is DKIM key rotation recommended, and what key length is secure?

Email marketer from Reddit explains that DKIM key rotation is crucial for mitigating risks associated with key compromise, insider threats, and vulnerabilities in cryptographic algorithms. They also mention that it enforces periodic checks on your email infrastructure.

Email marketer from Valimail explains that rotating DKIM keys limits the damage from a compromised key by reducing the time it can be exploited. It also validates that the key management process is working as intended.

Marketer from Email Geeks shares that cracking an RSA-512 private key from the public key is trivial, citing Yurichev's proof that it could be done in about 4 days on a Ryzen 5 3600. They add that while 1024 has not yet been factored by anyone, it's only a matter of time and money.

Email marketer from AuthSMTP highlights that DKIM key rotation is part of a proactive email security strategy, ensuring that security measures are regularly updated and preventing long-term exploitation of potential vulnerabilities.

Email marketer from Mailgun suggests rotating DKIM keys at least once a year. They explain that this practice helps maintain security and ensures the key management process is regularly reviewed and functional.

Email marketer from EmailToolTester recommends using a 2048-bit DKIM key for enhanced security. They explain that a longer key makes it significantly harder for attackers to forge your email signatures.

Marketer from Email Geeks explains that a key part of key rotation is removing old keys after a window of time to ensure validation. This process includes adding a new key, signing with the new key, and after a period, removing the old key's TXT record.

Email marketer from Proofpoint emphasizes that regular DKIM key rotation minimizes the window of opportunity for attackers if a key is compromised, and ensures the incident response plan is well understood.

Email marketer from SendGrid recommends a DKIM key length of 2048 bits because it is now the industry standard. Shorter keys are more vulnerable to attacks and can impact deliverability.

Email marketer from SparkPost states that DKIM rotation provides ongoing protection against sophisticated email attacks and maintains the integrity and trustworthiness of your email communications.

Email marketer from StackExchange responds that using at least 2048-bit DKIM keys are essential for ensuring adequate security against modern cryptographic attacks and for maintaining compliance with email authentication standards.

Marketer from Email Geeks shares a quote from m3aawg.org which states that frequent rotations standardize the rotation process and ensure institutional knowledge is available in case of an emergency compromise requiring an out-of-cycle key rotation.

Expert from Email Geeks explains that while RSA is considered legacy, 2048 is acceptable for DKIM signatures because the attack vectors are more likely to be insider, data leakage, or rubber hose rather than brute force, even for a 1024-bit key.

Expert from Spam Resource explains that while strict guidelines don't exist, rotating DKIM keys every 6 to 12 months is a good practice. This mitigates potential damage from compromised keys and enforces regular maintenance.

Expert from Email Geeks explains that DKIM key rotation reduces the window of exposure if a private key is compromised and ensures the rotation process is known when a compromise is suspected.

Expert from Word to the Wise answers that using a DKIM key length of 2048 bits is increasingly important for improved security and compliance with current email authentication standards.

Documentation from AWS SES Documentation answers that regularly rotating DKIM keys provides a defense-in-depth strategy. Even if a key isn't compromised, rotating it is a security best practice.

Documentation from Google Workspace Admin Help explains that DKIM key rotation reduces the risk of unauthorized use if a key is compromised. Regularly rotating keys limits the period a compromised key can be used, thereby minimizing potential damage from spoofing or phishing attacks.

Documentation from Microsoft Defender for Office 365 documentation recommends using a key length of 2048 bits for DKIM. They explain that while 1024-bit keys are still supported, 2048-bit keys offer better security against cryptographic attacks.

Documentation from RFC 6376, the DKIM standard, allows for the publication of multiple public keys for a domain. This enables key rotation without service interruption as senders can gradually switch to new keys while older keys remain valid for a transition period.