Policies
Policies
In Hyperledger Fabric, policies are the mechanism for infrastructure management. Fabric policies represent how members come to an agreement on accepting or rejecting changes to the network, a channel, or a smart contract.
Policies are agreed to by the channel members when the channel is originally configured, but they can also be modified as the channel evolves.
For example, they describe the criteria for adding or removing members from a channel, change how blocks are formed, or specify the number of organizations required to endorse a smart contract. All of these actions are described by a policy which defines who can perform the action. Simply put, everything you want to do on a Fabric network is controlled by a policy. Once they are written, policies evaluate the collection of signatures attached to transactions and proposals and validate if the signatures fulfill the governance agreed to by the network. Policies can be used in Channel Policies, Channel Modification Policies, Access Control Lists, Chaincode Lifecycle Policies, and Chaincode Endorsement Policies.
Peers
Peers are a fundamental element of the network because they host ledgers and smart contracts. Peers have an identity of their own and are managed by an administrator of an organization.
Ordering service nodes
Ordering service nodes order transactions into blocks and then distribute blocks to connected peers for validation and commitment. Ordering service nodes have an identity of their own, and are managed by an administrator of an organization.
Transport Layer Security (TLS)
Fabric supports secure communication between nodes using Transport Layer Security (TLS). TLS communication can use both one-way (server only) and two-way (server and client) authentication.