The problem is not the RSA math itself but that it is both extremely slow and implementing it is particularly susceptible to bugs and side channel attacks
https://blog.trailofbits.com/2019/07/08/fuck-rsa/
Most of the situations I encounter RSA are in projects where I hope RSA is implemented correctly. I have a lot of Let’s Encrypt certs that are still RSA and my main SSH keys are still RSA. All of these were generated quite some time ago. I understand the problem with projects that implement it incorrectly but I’d hope OpenSSH and certbot aren’t those projects 😥
Fact of the matter is RSA is perfectly secure still…and ECDSA/ED25519 should also be extinct given the rising need for post quantum cryptography
The problem is not the RSA math itself but that it is both extremely slow and implementing it is particularly susceptible to bugs and side channel attacks https://blog.trailofbits.com/2019/07/08/fuck-rsa/
Most of the situations I encounter RSA are in projects where I hope RSA is implemented correctly. I have a lot of Let’s Encrypt certs that are still RSA and my main SSH keys are still RSA. All of these were generated quite some time ago. I understand the problem with projects that implement it incorrectly but I’d hope OpenSSH and certbot aren’t those projects 😥
For Certbot, I think it’s even further up the chain - OpenSSL. And if you’re installing it to Apache or Nginx, its probably just OpenSSL again.