compressed/uncompressed public key addresses

[warut]

How can I tell if an address is created with a compressed or uncompressed public key?
Of course, if I know its private key, I can distinguish with the prefix (K/L or 5).

[dserrano5]

How can I tell if an address is created with a compressed or uncompressed public key?
Of course, if I know its private key, I can distinguish with the prefix (K/L or 5).

You can't tell the pubkey knowing only the address, so AFAIK you can't figure this out.

[DannyHamilton]

How can I tell if an address is created with a compressed or uncompressed public key?
Of course, if I know its private key, I can distinguish with the prefix (K/L or 5).

For what purpose would you want to know?

[warut]

How can I tell if an address is created with a compressed or uncompressed public key?
Of course, if I know its private key, I can distinguish with the prefix (K/L or 5).

You can't tell the pubkey knowing only the address, so AFAIK you can't figure this out.

Thanks, dserrano5. That's what I've expected.

[warut]

How can I tell if an address is created with a compressed or uncompressed public key?
Of course, if I know its private key, I can distinguish with the prefix (K/L or 5).

For what purpose would you want to know?

I have both types of addresses in my wallet, but I now prefer to use the compressed ones because of the free faucets.

[dserrano5]

I have both types of addresses in my wallet, but I now prefer to use the compressed ones because of the free faucets.

You should always be using new addresses anyway, and recent software doesn't create uncompressed keys anymore so don't worry about this. The fact that some uncompressed keys lie in your wallet isn't any problem at all. The "problem" (increased blockchain usage) happens only when spending from those keys, but you won't do that again as long as you receive payments on new, compressed ones.

[warut]

OK, thanks again, dserrano5.

[Dabs]

You can tell by analyzing the public key in the block chain after it has spent something. Compressed keys are shorter. Uncompressed keys are longer. Block Explorer might show the public key I think.

[warut]

You can tell by analyzing the public key in the block chain after it has spent something. Compressed keys are shorter. Uncompressed keys are longer. Block Explorer might show the public key I think.

Yea, I realized that too after posting the question.

[jackjack]

Dump your wallet contents, the public keys are inside it

[Dabs]

I think one concern is, you can't tell if you don't own it and it has not yet spent. Since the public key will not be in the blockchain. You can only tell, if it has spent any amount.