Test the security of your SSH keys

We will take the public key you paste here and, if it parses correctly, run it against two RSA key healthcheck algorithms: division by small primes, and batch-GCD against the (large) Cryptosense key database. More information can be found in this blog post.

SSH keys are only part of the whole picture. Our crypto discovery tool can scan your SSH, HTTPS, and mail servers for common configuration errors and detect whether you are vulnerable to attacks such as DROWN.

Handling SSH keys or SSL certs for your clients? Get in touch with us for a premium access to our key testing API.

Public SSH key

Your SSH key can be found in .ssh/id_rsa.pub. Don't paste your private key!

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Results

Small factors

RSA public keys are supposed to be the product of two large prime numbers. If a public key has a small divisor, it means that it was generated with a flawed algorithm.

Common factors

Factoring a single key is difficult, but in practice, with a large number of keys at hand, it is sometimes possible to find a common factor between keys. If such a factor exists, both keys can be factored.