Class X25519Session

X25519 key agreement using ephemeral key pairs.

Note that unless this key agreement is combined with an authentication method, such as public key signatures, it's vulnerable to man-in-the-middle attacks.

Implements

Constructors

constructor

Properties

acceptMessageLength offerMessageLength savedStateLength sharedKeyLength

Methods

accept clean finish getSessionKeys getSharedKey offer restoreState saveState

Constructors

constructor

Properties

ReadonlyacceptMessageLength

acceptMessageLength: 32 = ACCEPT_MESSAGE_LENGTH

Accept message length in bytes

ReadonlyofferMessageLength

offerMessageLength: 32 = OFFER_MESSAGE_LENGTH

Offer message length in bytes

ReadonlysavedStateLength

savedStateLength: 32 = SAVED_STATE_LENGTH

Saved state length in bytes *

ReadonlysharedKeyLength

sharedKeyLength: 32 = SHARED_KEY_LENGTH

Shared key length in bytes *

Methods

accept

  • accept(offerMsg): Uint8Array

  • Accept offer message and return new accept message, which should be sent back to the offering party.

    Also derives shared key, so the accepting party can call getSharedKey() right after calling accept.

    Parameters

    • offerMsg: Uint8Array

    Returns Uint8Array

clean

finish

  • finish(acceptMsg): this

  • Offering party finishes key agreement by receiving accept message and passing it to finish(). After calling finish(), offering party can call sharedKey() to get shared key.

    Parameters

    • acceptMsg: Uint8Array

    Returns this

getSessionKeys

getSharedKey

  • getSharedKey(): Uint8Array

  • Returns the agreed shared key.

    • Offering party should call this after finish().
    • Accepting party should call this after accept().

    Returns Uint8Array

offer

  • offer(): Uint8Array

  • Offer returns a new offer message, which should be send to the accepting party.

    Returns Uint8Array

restoreState

saveState

  • saveState(): Uint8Array

  • Serializes secret offering party state into byte array.

    This function should be called after offer() if the offering party cannot keep KeyAgreement instance in memory. When it receives accept message, it can create a new instance and call restoreState() on it with the serialized state to recover to continue the agreement.

    Returns Uint8Array

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