Interface X25519

ReadonlyPRIVATE_KEY_SIZE

ReadonlyPUBLIC_KEY_SIZE

generatePrivateKey

• generatePrivateKey(options?: RngOptions): Uint8Array<ArrayBuffer>

  32 random bytes from options.rng (default secure), unvalidated; the reference's x25519_new_private_key_using (random_data). A generator's own error, including rand's InvalidGenerator, propagates unwrapped.

  Parameters

  • Optionaloptions: RngOptions

  Returns Uint8Array<ArrayBuffer>

  Throws

  InvalidParameter unless options is an object or absent.

publicKey

• publicKey(privateKey: Uint8Array): Uint8Array<ArrayBuffer>

  The X25519 public key of privateKey (clamped per RFC 7748).

  Parameters

  • privateKey: Uint8Array

  Returns Uint8Array<ArrayBuffer>

  Throws

  InvalidParameter on a non-Uint8Array; InvalidSize on a wrong-length key.

sharedKey

• sharedKey(
      privateKey: Uint8Array,
      publicKey: Uint8Array,
  ): Uint8Array<ArrayBuffer>

  X25519 Diffie-Hellman, then HKDF-SHA-256 with salt "agreement" → 32 bytes (the reference's x25519_shared_key). A low-order publicKey (RFC 7748 §6.1) gives the all-zero shared secret and so one fixed key, whatever the private key: the reference calls x25519-dalek's diffie_hellman without checking was_contributory, and neither does this. Reject such peers yourself before deriving from an untrusted key.

  Parameters

  • privateKey: Uint8Array
  • publicKey: Uint8Array

  Returns Uint8Array<ArrayBuffer>

  Throws

  InvalidParameter on a non-Uint8Array; InvalidSize on a wrong length.