I recently had a situation where I lost an old private key (write error; realized this too late). In regenerating keys and replacing the public keys on various sites, I noticed that the public keys were identical. I did use the same key size, algorithms, and passphrases as the older set, but I thought that there was supposed to be randomness involved in key generation. Should I be concerned about the state of my computer's rng?
I'm concerned that this question may be getting too personal, but I did not find any information on stackexchange or via search engines so I thought this information might be useful for another individual's later searches. I've often found useful answers lurking on stackexchange and hope this may provide the same to someone down the line.
I used the Seahorse GUI frontend. File > New > GPG > entered passphrase, selected RSA and 4096 > generated keys. I then exported the new key from the 'my keys' tab (recounting this from memory) and double-checked it was a public key. Then I opened properties of the new key, did the complete export, and double-checked that it exported a private key.
I could not reproduce this (generate another key with identical public key), but the old public key did work with the new private key. I do not know the old key id (it was only in use for a week or so). I generated a new key; did not find old key file. The only settings I changed in Seahorse was to increase key size; I did not opt for any deterministic key generation. I don't see how my entropy could be identical.