---
layout: default
title: 'Re: Questions about BitCoin'
date: 2009-04-18 18:16
grand_parent: Emails
parent: Mike Hearn
nav_order: 5
---

# Re: Questions about BitCoin

The email on the Cryptography Mailing List that announced Bitcoin publicly to the world.
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---

```
From: Satoshi Nakamoto <satoshin@gmx.com>
Date: Sat, Apr 18, 2009 at 6:16 PM
To: Mike Hearn <mike@plan99.net>
Subject: Re: Questions about BitCoin
 
I sent back 32.51 and 50.00.
 
I badly wanted to find some way to include a comment with indirect transfers, but there just wasn't a way to do it.  Bitcoin uses EC-DSA, which was essential for making the block chain compact enough to be practical with today's technology because its signatures are an order of magnitude smaller than RSA.  But EC-DSA can't encrypt messages like RSA, it can only be used to verify signatures.
```