What is “Key Splitting”? When would I use it?

Question

Here is some github code to create split keys.

• Is Key Splitting the same as Multi Sig?

• What are the benefits of Key Splitting, what's it used for?

• How does it relate to P2SH or any other relevant BIP?

• How are split keys used in a transaction?

Answer 1

• No. Multisignature transactions involve multiple keys/signatures, whereas this involves splitting up one key.
• As far as I know, it's not used at all in production. There are a whole host of issues.
• P2SH was created to make multisignature transactions easier to implement for e-wallet providers and merchants, and to move the burden of multisignature transactions from the sender to the reciever.

• Like so:

  1. Generate a key
  2. Split the key up, store the pieces in different places
  3. Put the key back together
  4. Sign transactions

  The major problem with split-key transactions is that you need a trusted third party. When they generate the key, they could secretly store it. When they put the key back together, they could secretly sign a transaction that stole all of your bitcoins.