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End-to-End Encryption

Narrowlink relies on selected transport protocols for data encryption by default. If you use the Wss protocol (WebSocket with TLS) or peer to peer mode, your data will be encrypted, which is enabled by default. However, if you use Ws (WebSocket without TLS), your data will be sent in plain text. Additionally, these protocols serve as transport methods, so if you choose a secure transport protocol, your communication is only encrypted between the client and the gateway, as well as between the agent and the gateway. As a result, the gateway retains the capability to access your packets. To add an extra layer of security to your data, you can utilize end-to-end encryption.

Narrowlink employs the Xchacha20-Poly1305 algorithm for end-to-end encryption, and passphrase-based key derivation based on SHA3-256. It also uses HMAC-SHA256 for signing tunnel destinations. Both the encryption and signing processes take place on both the client and agent sides, necessitating manual key transfer.

Enabling End-to-End Encryption

Setting up end-to-end encryption is a straightforward process. You need to establish a shared key between the client and the agent. This key will be used for both encryption and decryption of data.

  1. Agent Configuration Setup:

In the agent configuration file, you must insert the following line:

- !PassPhrase # Enabling end to end encryption (optional)
phrase: "your_key" # key for end to end encryption
policy: Lax # Lax or Strict (default: Lax) Lax allows clients to connect without a key, while Strict requires a key

Replace "your_key" with the actual key you want to use for encryption.

  1. Client Command Setup:

You need to use the same key to the client command arguments by adding -k or --key flag to your command, for example:

narrowlink forward -k your_key ...
narrowlink proxy -k your_key ...
narrowlink connect -k your_key ...

End-to-End Encryption Policy Enforcement

Narrowlink enables you to enforce an end-to-end encryption policy on the agent side. There are two ways to implement this policy:

  • Lax: The agent will accept both encrypted and unencrypted connections. (Default)
  • Strict: The agent will only accept encrypted connections.

To enforce the policy, add the following line to the agent configuration file:

    policy: Strict # Strict or Lax