Some web wallets like blockchain.info give you more than 1 address, how to detect two addresses from the same wallet?.
example:
if my friend makes blockchain.info wallet "it will give him x address" after 1 day a wallet give him other address "y address" how to know "x address and y address " from the same wallet?.
Your friend can check in the Blockchain.info wallet with Settings > Addresses > Manage.
If you're asking how
you (or anyone watching the network) can detect this, there's no way to know, unless the addresses have been used together to sign a transaction. If both addresses have been used as inputs in the same transaction, they'll be grouped together on Walletexplorer as TryNinja points out:
You can't really know. What you can try to do is link multiple addresses to the same wallet by using tools/websites like this one[1]. But that's all.
[1]
https://www.walletexplorer.com/But because Bitcoin is pseudonymous, it only provides an alphanumeric wallet identifier, and addresses can be shared by multiple wallets due to address importing. So you can't link it to an identity without someone claiming the public address or demonstrating control of the private key.
