The concept of Multisig can be implemented in different ways in different cryptocurrencies:

Bitcoin/Litecoin: As Bitcoin(BTC) and Litecoin(LTC) are from the same family, the implementation of Multisig can be done in the same way. P2SH-P2WSH is the protocol that Coinome has used for implementing mMultisig. A P2SH address can support arbitrary sets of N keys, any M of which are required to transact — this is commonly referred to as “M-of-N.” M out of N cosigners should sign the transaction for it to get processed. M is always less than N. Here, Three public keys together derive the address.

Ethereum: There is no protocol followed for Ethereum. An exclusive code needs to be written to implement Multisig for Ethereum in the language Solidity. The address is then generated where the rules are governed using a smart contract.

Ripple: Ripple has the same M(N) keys concept applied while implementation but in the form of weightage.

NEM: NEM’s current implementation of multisig is “M-of-N”, meaning M can be any number equal to or less than N, i.e., 1-of-4, 2-of-3, 3-of-5 and so on. NEM also allows “N-of-N” accounts, i.e., 1-of-1, 2-of-2, 5-of-5 and so on. With N-of-N accounts, the transaction have to have all N cosignatories sign the account, but to edit the signers on the account it is “N-1.” For example, if you create an account with 3 cosignatories only 2 signers are necessary to delete or change the third signature – hence N-1 (3 being “N” in the above example).