EncryptedDirectMessage class

A special event with kind 4, meaning "encrypted direct message".

content MUST be equal to the base64-encoded, aes-256-cbc encrypted string of anything a user wants to write, encrypted using a shared nip4cipher generated by combining the recipient's public-key with the sender's private-key; this appended by the base64-encoded initialization vector as if it was a querystring parameter named "iv". The format is the following: "content": "<encrypted_text>?iv=<initialization_vector>".

tags MUST contain an entry identifying the receiver of the message (such that relays may naturally forward this event to them), in the form "p", "pubkey, as a hex string".

tags MAY contain an entry identifying the previous message in a conversation or a message we are explicitly replying to (such that contextual, more organized conversations may happen), in the form "e", "event_id".

Note: By default in the libsecp256k1 ECDH implementation, the secret is the SHA256 hash of the shared point (both X and Y coordinates). In Nostr, only the X coordinate of the shared point is used as the secret and it is NOT hashed. If using libsecp256k1, a custom function that copies the X coordinate must be passed as the hashfp argument in secp256k1_ecdh.

NIP-04 considered harmful, READ: https://github.com/ethicnology/dart-nostr/issues/15 and https://github.com/nostr-protocol/nips/issues/107

Inheritance
Annotations
  • @Deprecated(""" NIP-04 a.k.a EncryptedDirectMessage is controversial, please READ: - https://github.com/ethicnology/dart-nostr/issues/15 - https://github.com/nostr-protocol/nips/issues/107 """)

Constructors

EncryptedDirectMessage(Event event, {dynamic verify = true})
Default constructor
EncryptedDirectMessage.receive(Event event, {dynamic verify = true})
receive an EncryptedDirectMessage
EncryptedDirectMessage.redact(String senderPrivkey, String receiverPubkey, String message)
prepare a EncryptedDirectMessage to send quickly with the minimal needed params
factory

Properties

content ↔ String
arbitrary string
getter/setter pairinherited
createdAt ↔ int
unix timestamp in seconds
getter/setter pairinherited
hashCode → int
The hash code for this object.
no setterinherited
id ↔ String
32-bytes hex-encoded sha256 of the the serialized event data (hex)
getter/setter pairinherited
kind ↔ int
  • 0: set_metadata: the content is set to a stringified JSON object {name:
  • 1: text_note: the content is set to the text content of a note (anything the user wants to say). Non-plaintext notes should instead use kind 1000-10000 as described in NIP-16.
  • 2: recommend_server: the content is set to the URL (e.g., wss://somerelay.com) of a relay the event creator wants to recommend to its followers.
    • getter/setter pairinherited
    nonce → String
    get nonce/IV
    no setter
    previous → String?
    get previous event id –> MAY contain an entry identifying the previous message in a conversation or a message we are explicitly replying to.
    no setter
    pubkey ↔ String
    32-bytes hex-encoded public key of the event creator (hex)
    getter/setter pairinherited
    receiver → String?
    get receiver public key
    no setter
    runtimeType → Type
    A representation of the runtime type of the object.
    no setterinherited
    sender → String?
    get sender public key
    no setter
    sig ↔ String
    64-bytes signature of the sha256 hash of the serialized event data, which is the same as the "id" field
    getter/setter pairinherited
    subscriptionId ↔ String?
    subscription_id is a random string that should be used to represent a subscription.
    getter/setter pairinherited
    tags ↔ List<List<String>>
    The tags array can store a tag identifier as the first element of each subarray, plus arbitrary information afterward (always as strings).
    getter/setter pairinherited

    Methods

    getEventId() → String
    To obtain the event.id, we sha256 the serialized event. The serialization is done over the UTF-8 JSON-serialized string (with no white space or line breaks) of the following structure:
    inherited
    getPlaintext(String privkey) → String
    get the deciphered message a.k.a. plaintext
    getSignature(String privateKey) → String
    Each user has a keypair. Signatures, public key, and encodings are done according to the Schnorr signatures standard for the curve secp256k1 64-bytes signature of the sha256 hash of the serialized event data, which is the same as the "id" field
    inherited
    isValid() → bool
    Verify if event checks such as id, signature, non-futuristic are valid Performances could be a reason to disable event checks
    inherited
    noSuchMethod(Invocation invocation) → dynamic
    Invoked when a nonexistent method or property is accessed.
    inherited
    serialize() → String
    Serialize to nostr event message
    inherited
    toJson() → Map<String, dynamic>
    Serialize an event in JSON
    inherited
    toString() → String
    A string representation of this object.
    inherited

    Operators

    operator ==(Object other) → bool
    The equality operator.
    inherited