How to identify contributors in an ICO in order to send them the tokens manually

[tunali]

Hi guys, I'm in the process of creating an ICO that'll collect donations which will cater for some orphanages in my community. However, I'm trying to find a solution to the token distribution problem. I'll be distributing the tokens to the contributors manually i.e. I'll be sending tokens to the contributors at a certain time every day. My problem is how to identify the contributors correctly. I'm planning to ask every contributor to email me the amount of Ether they sent me along with their transaction id and their ethereum wallet address to receive their custom tokens from me. The problem is; I think anybody could get the information about the amount of ether sent to my address and the transaction id by looking up my address on etherscan.io. So how can I differentiate the genuine contributor from an imposter?

[MadGamer]

That's the whole purpose from creating Ethereum, smart contracts. I'm not much of a developer but you should be able to do easily so the tokens are automatically sent once the ETH are received, start by checking the Ether documentation and APIs etc.

[DarnellL]

Tokens must be sent to the wallet from which you received ETH:

Contributor1 -> ETH -> Your ICO wallet
Your ICO wallet ->Tokens -> Contributor1

Contributor2 -> ETH -> Your ICO wallet
Your ICO wallet ->Tokens -> Contributor2

. . .

ContributorN -> ETH -> Your ICO wallet
Your ICO wallet ->Tokens -> ContributorN

[tunali]

This makes total sense for purchases with ethereum. However, I'm also offering token purchase with bitcoin and litecoin. For instance when someone sends bitcoin, what can I ask them to provide (other than their ethereum address to send my custom tokens) to verify that they are indeed the ones who sent me the bitcoin? I thought of transaction id and their bitcoin wallet address but that is public information. Anyone can look up my bitcoin address and see the details of all the transactions I received, copy the sender's address and transaction id and claim to be the one who sent the bitcoins and ask for their tokens. Am I getting something wrong here? How do I get around this problem?

[Intellecual Romanticist]

Simple Rule1: You will only send the Token to the address you receive donations from.
Simple Rule2: Ask them to send you their address upon signing up.