When you generate a private key, it's not supposed to be easily transported between devices. There's a thing called a Hardware Security Module (HSM) which is meant to generate and securely store keys. eMudhra needed to generate keys for some certificates, but their new HSM chips were delayed, so they decided to generate the keys on someone else's HSM. They then used a python script to try to export the keys, which would have required disabling security features of the HSM and packaging the keys into an encrypted "blob". When they then extracted the keys from the blob later, it cut off most of the key, leaving only one byte of the key's value (resulting in a key value between 1-255).

They initially signed the certs with the full key, but in June 2025 they encountered a key mismatch, where their keys (the transferred keys with the short value) didn't match. eMudhra said they used the wrong key the first time, and resigned the certs with the transferred insecure keys instead.