<p>An address has 1 + 20 + 4 bytes, which has a total of 200 bits. Each of the Base58 characters contain log_2 58 bits of information, which is approximately 5.858. If one created an address that has the public key hash 0000...00, the result would be a 5-6 character address, due to the checksum. To prevent this, Satoshi decided to add "1"s for each 0x00 byte in front of the address. Those "1"s each contain 8 bits of information instead of 5.85... As they carry more information, it's harder to find an address starting with those 1s.</p>

CC BY-SA 3.0
2018-04-03T07:50:42.803Z
2018-04-03T07:50:42.803Z
MCCCS
<blockquote>
  <p><img src="https://i.sstatic.net/b3xXn.png" alt=""></p>
</blockquote>

<p>Here's a table I got from <a href="https://en.bitcoin.it/wiki/Vanitygen" rel="nofollow noreferrer">bitcoin wiki</a>.</p>

<p>They say:</p>

<blockquote>
  <p>A special case, leading numbers 1 (one) is especially difficult.</p>
</blockquote>

<p>But why?</p>

CC BY-SA 3.0
2016-08-28T15:35:18.517Z
Take a look at this answer. http://bitcoin.stackexchange.com/questions/10828/vanitygen-why-is-it-easier-to-generate-an-address-that-starts-with-a-capital-le
m1xolyd1an
CC BY-SA 3.0
2016-10-25T19:25:10.807Z
See this question's answer [here](http://bitcoin.stackexchange.com/questions/10828/vanitygen-why-is-it-easier-to-generate-an-address-that-starts-with-a-capital-le)
user2716556
<address><ecdsa><vanity-address><vanitygen>
Why is it harder to generate addresses starting with 1s?
MCCCS
# Why is it harder to generate addresses starting with 1s?

(Asked by: username_0 on 2016-08-28)

> ![](https://i.sstatic.net/b3xXn.png)

Here's a table I got from [bitcoin wiki](https://en.bitcoin.it/wiki/Vanitygen).

They say:

> A special case, leading numbers 1 (one) is especially difficult.

But why?

**Tags:** address, ecdsa, vanity-address, vanitygen

> **Comments:**
> **username_1**: Take a look at this answer. http://bitcoin.stackexchange.com/questions/10828/vanitygen-why-is-it-easier-to-generate-an-address-that-starts-with-a-capital-le  
> **username_2**: See this question's answer [here](http://bitcoin.stackexchange.com/questions/10828/vanitygen-why-is-it-easier-to-generate-an-address-that-starts-with-a-capital-le)  

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## 1 answers

### Answer by username_0 on 2018-04-03. Score: 0 | Accepted answer

An address has 1 + 20 + 4 bytes, which has a total of 200 bits. Each of the Base58 characters contain log\_2 58 bits of information, which is approximately 5.858. If one created an address that has the public key hash 0000...00, the result would be a 5-6 character address, due to the checksum. To prevent this, Satoshi decided to add "1"s for each 0x00 byte in front of the address. Those "1"s each contain 8 bits of information instead of 5.85... As they carry more information, it's harder to find an address starting with those 1s.


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