import { PublicKey } from "@solana/web3.js";
import type { SerializedUTXO } from "./model.js";
/**
 * Encrypted UTXO note — can be broadcast alongside a transaction so the
 * recipient can recover their note without a server.
 */
export type EncryptedNote = {
    /** 24-byte NaCl box nonce */
    nonce: Uint8Array;
    /** Ciphertext containing amount + blinding + privateKey */
    ciphertext: Uint8Array;
    /** Sender's ephemeral 32-byte X25519 public key */
    senderEphemeralPubkey: Uint8Array;
};
/**
 * Derive a NaCl X25519 encryption keypair from a UTXO private key.
 * The keypair is deterministic: same privateKey always yields the same pair.
 */
export declare function deriveEncryptionKeypair(privateKey: bigint): {
    publicKey: Uint8Array;
    secretKey: Uint8Array;
};
/**
 * Encrypt a UTXO so the recipient can recover it from on-chain events.
 *
 * Plaintext layout (72 bytes):
 *   [0..8]   amount  — 8-byte little-endian u64
 *   [8..40]  blinding — 32-byte big-endian field element
 *   [40..72] privateKey — 32-byte big-endian field element
 *
 * Uses ephemeral-key NaCl box so the sender key is single-use.
 */
export declare function encryptUTXONote(utxo: SerializedUTXO & {
    privateKey: bigint;
}, recipientEncPubkey: Uint8Array): EncryptedNote;
/**
 * Try to decrypt an encrypted UTXO note using the recipient's private key.
 * Returns the SerializedUTXO if decryption succeeds and the commitment
 * matches, or `null` if the note was not intended for this key.
 */
export declare function decryptUTXONote(note: EncryptedNote, recipientPrivateKey: bigint, commitment: Uint8Array, mintAddress: PublicKey): SerializedUTXO | null;