Function hdk::x_salsa20_poly1305::x_salsa20_poly1305_encrypt

source · 
pub fn x_salsa20_poly1305_encrypt(
    key_ref: XSalsa20Poly1305KeyRef,
    data: XSalsa20Poly1305Data
) -> ExternResult<XSalsa20Poly1305EncryptedData>
Expand description

Libsodium secret-key authenticated encryption: secretbox.

Libsodium symmetric encryption (a shared key to encrypt/decrypt) is called secretbox. Secretbox can be used directly to hide data and is part of cryptographic systems such as saltpack.

Important information about secretbox:

  • Wasm memory is NOT secure, a compromised host can steal the key.
  • The key is SECRET, anyone with the key and nonce can read the encrypted message.
  • The nonce is PUBLIC and UNIQUE, it must NEVER be re-used (so we don’t allow it to be set).
  • Secretbox is designed for ‘small’ data, break large data into chunks with unique nonces.
  • Secretbox is NOT quantum resistant.

@todo shift all the secret handling into lair so that we only work with opaque key references.

If you want to hide data:

  • Consider using capability tokens and/or dedicated DHT networks to control access.
  • Consider how the shared key is being distributed, e.g. maybe use a key exchange protocol.
  • Consider that a hybrid approach between network access + encryption might be best.
  • Consider that encrypted data cannot be validated effectively by the public DHT.

The main use-case is to control access to data that may be broadcast across a semi-trusted or untrusted context, where the intended recipients have all negotiated or shared a key outside that context.

If you want to encrypt content so that a specific recipient (i.e. public key) can decrypt it then see the libsodium box algorithm or similar.

See https://doc.libsodium.org/secret-key_cryptography/secretbox See https://nacl.cr.yp.to/secretbox.html