Under normal circumstances it should be impossible to generate the private key that corresponds to public key. This is because a public key is mathematically de

Under normal circumstances it should be impossible to generate the private key that corresponds to public key. This is because a public key is mathematically derived from it's private key in a way that both forces a brute force test of the entire key domain as the only attack and requires that the each individual test is expensive. In general sharing public keys should be safe. There are be exceptions: If the key generator is somehow flawed the brute force search can be narrowed. Also, the rate you can test is constantly increasing so in 1995 512 bit RSA keys were "safe" but I wouldn't trust them now. A realistic attacker probably isn't going to attack the public key but if the key was generated by "rob@example.com" he may try attacks against publicly visible machines in example.com to obtain the correct private key. That's probably the worst case scenario and it also may not bear fruit. Don't forget that you can put a pass phrase on your private key to enhance your own security.