SK-SNARK is a cryptographic proof that allows one of the parties to prove that it has certain information without disclosing that information. This proof is possible using a secret key created before the transaction takes place.
ZK-SNARK uses a concept known as “zero knowledge proof”.
The idea behind this was first developed in the 1980s. Simply put, “zero knowledge proof” is a situation in which each of the two parties in a transaction is able to verify with each other that they have a certain set of information, without revealing, at the same time, what that information is.

For most other types of evidence, at least one of the two parties must have access to all information. A traditional proof can be compared to a password used to access an online network. The user sends the password, and the network itself checks the contents of the password to see if it is correct. To do this, the network must also have access to the contents of the password.

A Zero Knowledge Proof version of this situation would require the user to prove to the network (through mathematical evidence) that he has the correct password without revealing the password itself. The advantages of privacy and security in this situation are clear: if the network does not have the password stored somewhere for verification purposes, the password cannot be stolen.

The mathematical basis of ZK-SNARK is complex. However, such evidence allows one of the parties to demonstrate not only that there is certain information, but also that the party concerned is aware of that information. In SourceLess Blockchain ZK-SNARK can be verified almost instantly, and the protocol does not require any interaction between tester and verifier.

Another attribute of ZK-SNARK in SourceLess Blockchain is its ability to minimize up to less than 1MB of nodes in the network, making it possible to place a node at each wallet holder.