!!! 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.!! Encoding a Bitcoin address
There are currently two address formats in common use and both are implemented using the [Base58Check] [encoding] of the [hash] of either:

Pay-to-script-hash ([P2SH]) (Newer [{$pagename}])
payload is: 
{{{
 [RIPEMD160] ( [SHA256|https://en.bitcoin.it/wiki/SHA256] (redeemScript))
}}}
where redeemScript is a script the wallet knows how to spend; version {{{0x05}}} (these addresses begin with the digit '3') 
(eg: 3J98t1WpEZ73CNmQviecrnyiWrnqRhWNLy)

Pay-to-pubkey-hash (P2PKH): 
payload is 
{{{
 [RIPEMD160] ( [SHA256] (ECDSA_publicKey))
}}}
where [ECDSA]_publicKey is a [Public Key] the wallet knows the [Private Key] for; version {{{0x00}}} (these addresses begin with the digit '1') \\
(eg: {{{1BvBMSEYstWetqTFn5Au4m4GFg7xJaNVN2}}})

!! [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 [MD5] 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' }]