!!! Overview
[{$pagename}] is an [identifier] of 26-35 alphanumeric characters, beginning with the number 1 or 3, that represents a possible destination for a [bitcoin] payment. 

[{$pagename}] can be generated at no cost by any user of [Bitcoin]. 

For [example], using Bitcoin Core, one can click "New Address" and be assigned an address. It is also possible to get a [{$pagename}] using an account at an exchange or online [cryptocurrency wallet] service.

There are currently two address formats in common use:
* Common [P2PKH] which begin with the number 1, eg: 1BvBMSEYstWetqTFn5Au4m4GFg7xJaNVN2.
* Newer [P2SH] type starting with the number 3, eg: 3J98t1WpEZ73CNmQviecrnyiWrnqRhWNLy.

!! [RIPEMD-160] and [SHA256] used for [{$pagename}]
[RIPEMD-160] was used because it produces a shorter hash output. This permits bitcoin addresses to be as short as possible without compromising security. The exact reason why [SHA256] was used in combination with [RIPEMD-160] is not known. The two leading theories are:

* There was concern that [RIPEMD] might have some defect. [SHA256] was believed to be more secure. The hope was that the two combined would be stronger than [RIPEMD] alone.
* There was a concern about possible weaknesses in the [MD] structure itself, such as a length extension attack. Two hashes combined result in a composite hash that does not have a [Merkle-Damgard construction] and so is not vulnerable to these attacks.


!! More Information
There might be more information for this subject on one of the following:
[{ReferringPagesPlugin before='*' after='\n' }]