Can A PRNG Be Used To Generate Multiple Private Keys for ECDSA? Suppose Alice seeds a cryptographically strong Pseudo Random Number Generator with a truly random number, and keeps it secret. Alice then uses the output of the PRNG to generate several 256-bit numbers in sequence. Each of those 256-bit numbers is then used as an ECDSA private key, public keys are generated from them, and those public keys are sent out in the open. The private keys are either kept secret, or destroyed.

An attacker, Mallory, collects a bunch of public keys, some of which belong to Alice. Two questions:


If not told explicitly, can Mallory figure out which keys belong to Alice?
If Mallory does know which keys belong to Alice, can he figure out any of the private keys (or the initial seed)?


My concern is that, since the private keys are mathematically related, information about their relation may be leaked through the ECDSA public key generation (Q = kG). Most implementations of ECDSA I have seen use a PRNG that is frequently re-seeded, like OpenSSL. Presumably, though, one could generate multiple keys sequentially without a re-seed occurring. That being the case, I assume the above is safe. I am, however, having a hard time coming up with a proof for it.
The most important property of cryptographic PRNGs is that it's indistinguishable from true random numbers, unless you know the seed, or you have huge computational resources. Two important consequences of this requirement are:


You can't find the seed from observing the output
You can't predict more outputs from observing some of them.


An attacker who can do either of those, either has broken the cryptography used in the PRNG, or he has computational resources exceeding the security level of the PRNG. For typical security levels of at least 128 bits, nobody on earth has the required resources.