Cracking a 512-bit DKIM key for less than $8 in the cloud (dmarcchecker.app)

Article summary

Researchers cracked a 512-bit DKIM key for less than $8 in the cloud, demonstrating the insecurity of short RSA keys. The key was factored using the Number Field Sieve algorithm on a rented cloud server with 8 dedicated vCPUs. The cracked key allowed the researchers to send DKIM-signed test emails that passed verification checks on some major email providers. This highlights the need for domain owners to review their DNS settings and use secure DKIM keys.

Main themes

• DKIM key security
• RSA key length
• Email security
• Cloud computing
• Cryptography

What commenters say

• The security of email is often overestimated, and the use of short RSA keys is a significant vulnerability.
• The cost of factoring larger RSA keys, such as 1024-bit or 2048-bit keys, is much higher than previously suggested, making them more secure.
• Some argue that the cost of factoring larger RSA keys is not as high as others claim, and that it is possible to factor them with significant computational power.
• The use of short RSA keys is a problem that can be exploited by malicious actors, and it is essential to phase out their use in favor of more secure alternatives.
• The security of email depends on various factors, including the use of secure protocols and the implementation of proper security measures by email providers.
• There is a disagreement about the cost and feasibility of factoring larger RSA keys, with some arguing that it is more expensive and difficult than others claim.