```python

from beem.steem import Steem
from beemgraphenebase.account import PrivateKey

def validate_private_key(steem_instance, account, private_key):
    try:
        public_key = str(PrivateKey(private_key).pubkey)
    except ValueError as e:
        if 'Base58' in e.args[0]:
                raise ValueError("Invalid private key")
        raise

    accounts = steem_instance.wallet.getAccountsFromPublicKey(str(public_key))
    if not account in accounts:
        raise ValueError("Invalid private key")

if __name__ == '__main__':
    s = Steem(node=["https://api.steemit.com"])
    validate_private_key(s, '<steem_username>', '<private_key>')
```
***

This example uses Beem library but it's possible with every client/library. You need to utilize the ```get_key_references``` [call](http://steem.readthedocs.io/en/latest/steem.html#steem.steemd.Steemd.get_key_references) on steem nodes.