user6024: Like the question states, is it currently possible in the Bitcoin blockchain to send coins to an address, but have the transaction written into a block or validated only after two parties sign messages into the blockchain that the funds should be released?
If it does exist, how does this technically work? 
A comment describing or linking to something similar to this or on the off-chain level would be appreciated too.

user6454: It's a built-in blockchain feature called a multisig transaction. 
https://en.bitcoin.it/wiki/BIP_0010

6024: <p>Like the question states, is it currently possible in the Bitcoin blockchain to send coins to an address, but have the transaction written into a block or validated only after two parties sign messages into the blockchain that the funds should be released?</p>

<p>If it does exist, how does this technically work? </p>

<p>A comment describing or linking to something similar to this or on the off-chain level would be appreciated too.</p>
 6454: <p>It's a built-in blockchain feature called a multisig transaction. </p>

<p><a href="https://en.bitcoin.it/wiki/BIP_0010" rel="nofollow">https://en.bitcoin.it/wiki/BIP_0010</a></p>
