NIX 2-Way Ghosting

Sender and receiver privacy in one address-less transaction

One way privacy overview

NIX Ghost Vault feature is a technology that provides privacy to either the sender or the receiver. NIX are not directly stored into the vault, as they are first converted to Sigma mints by the implementation of the optional privacy Ghost Protocol. User’s Sigma mints are combined into an accumulator, thus eliminating the possibility of identifying which coins belong to each user.

The procedure of sending coins to the Ghost Vault is called “ghosting”, which provides the receiver with full privacy, as the destination is a hidden place and the sending address is public. Coins kept in the vault remain private. On the other hand, sending coins from the Ghost Vault to an address, is called “unghosting”; here the sending address, being represented by the vault, is private, giving sender privacy, yet the receiving address is a public and identifiable location.

Although this feature is first NIX’s privacy implementation, it does not offer sender and receiver privacy at once.

NIX Platform Explains it's Ghost Vault

2 Way Privacy: Commitment Key Packs

As the focus is to provide sender/receiver full privacy in one transaction, NIX team introduces the very first concept of 2 way privacy by implementing Pedersen Anonymous Deposit scheme called Commitment Key Packs, which enables full Zero-Knowledge proof transaction privacy between sender and receiver: 2 Way Ghosting mechanisn.

2 Way Ghosting

This never-done-before technology enables the ability to launch powerful private smart contracts on chain while allowing ZK-proof transaction edged privacy.

Although the technical procedure for achieving sender/receiver privacy in one transaction is complex in the backstage, it can be summarized as simple as sending coins from one Ghost Vault to another in the diagram below:

NIX Platform Explains 2-Way Ghosting

Every time NIX coins are ghosted, they go through the Ghost Protocol before entering the Ghost Vault, so they get destroyed and converted into Sigma mints; which, in turn, are stored into the vault. Once in there, NIX are no longer existent, instead, users own mixed-Sigma mints that are impossible to trace.

Originally before leaving the Ghost Vault, Sigma mints needed to be converted back to NIX through a process called un-ghosting.

If those re-created NIX coins leave the vault by being sent to a NIX address, they become public, and privacy is no-longer available as they can be traced throughout the blockchain.

To avoid that from happening, NIX Platform has created a Key list containing customized one-time-keys (Ghost Keys) which can be found in NIX core wallet. These receivers’ one-time-keys are used to unlock Sigma mints. The receiver must provide the sender with one Ghost Key.

Now, instead of unghosting NIX to a public address, the sender inputs receiver’s one-time key so that previously ghosted NIX get converted into new ghosted NIX and get deposited directly into receiver’s Ghost Vault without compromising any security. Once a Ghost Key gets used it gets burnt.

Conclusion

2 Way Ghosting feature offers full sender and receiver privacy in one transaction without the need of NIX addresses. This mechanism is so powerful that there is no way for user history to be compromised as address-less transactions are performed.

Commitment Key Packs technical paper here, demonstration video here.