Metadata

Metadata is structured information about a message or a transaction, for example the time and location it was sent and the kb size of the message as opposed to its content.

Nym nodes

Nym nodes operate the Nym mixnet. They serve as entry and exit points to the network and as mix nodes, adding cover traffic and mixing communications by adding micro timing delays to obscure patterns of communication.

NYM token

The NYM token is the native token of the Nym mixnet. It is a utility token used to access the mixnet, serving as reputation for nodes to assure good quality of service, and rewards for operators and stakers.

Bonding

Means the joining of a Nym node to the mixnet. Nym is permissionless and decentralised, meaning anyone can run a mix node and join the network. In order for the system to know whether a node is part of the network or not, an operator has to “bond” their node by staking NYM tokens on their node via the Nym wallet.

Stake saturation

Nym nodes have a reputation measured in “stake”. Anyone holding Nym tokens can stake on a Nym node and earn a share of their rewards. The higher a Nym node’s reputation, the better the chances of being selected to mix traffic and earn rewards. To prevent centralisation of stake on a few high performing nodes, there is a point of saturation after which an increase in stake does nothing to help a node’s chances of selection. Any additional stake on top of this stake saturation point is effectively wasted. When staking, check a node’s stake saturation. If it is near or over 100%, it is better to stake on a different node to optimise returns.

Sphinx encryption and Outfox

Sphinx encryption is a cryptographic message format used to relay anonymised messages within the mixnet, also used by the Lightning Network. It has five layers of encryption, each layer only revealing only where the packet needs to be sent to next, as it is relayed through two gateways and three mix nodes. This makes it impossible for any part of the infrastructure to know both the sender and the receiver of the message.

Outfox is an optimised version of Sphinx.

Validators

A node type that secures and validates blocks in blockchains by running a consensus algorithm. The Nym mixnet uses the Nyx blockchain to run its token economics. Nyx validators

Zero-knowledge proofs

Cryptographic techniques that make it possible to mathematically prove something to be true without having to reveal the evidence.

zk-nyms

A cryptographic protocol enabling the issuance and verification of anonymous credentials, based on Coconut protocol. The scheme allows users to prove certain attributes or properties about themselves without compromising their identity, achieved through the use of zero-knowledge proofs. It is used in the Nym mixnet in order to enable privacy preserving payments for mixnet usage. Nyx validators issue credentials via the ‘nym-API’, enabling people to spend their NYM tokens on privacy preserving credentials, called bandwidth credentials, using the zk-nym scheme.

The zk-nym scheme has been developed further into a decentralised, anonymous e-cash scheme.

Bandwidth credentials

Anonymous credentials based on zk-nyms that provide an allowance for using the Nym mixnet. Users can swap NYM tokens for bandwidth credentials, ensuring that their mixnet usage is delinked from their wallet. In most other systems, your payment details will “leak” at the point of paying for a service. Using zk-nyms, you can pay and prove your right to use the mixnet without leaking any unnecessary information.

Anonymity set

Entities that are grouped together to make it hard to distinguish one from the other, with each entity therefore contributing to everyone else’s anonymity. In the case of the Nym mixnet, this refers to the mixing of traffic flowing through the network such that it becomes impossible to trace a person’s communication as it is obscured by everyone else’s communications flows.