import { PrivateKey, PublicKey } from "../crypto.js";
/**
 * Encrypts a binary memo payload with Hive memo key agreement.
 *
 * @param private_key - Sender memo private key.
 * @param public_key - Recipient memo public key.
 * @param message - Serialized plaintext memo bytes.
 * @param nonce - Optional nonce string for deterministic tests.
 * @returns Nonce, ciphertext, and checksum for an encrypted memo envelope.
 *
 * @remarks
 * The AES key is derived from the secp256k1 shared secret and nonce, matching
 * Hive's encrypted memo convention. Application code should normally use
 * `Memo.encode`, which handles string framing and base58 packaging.
 *
 * @example
 * ```ts
 * const encrypted = encrypt(senderMemoKey, recipientMemoPublicKey, memoBytes)
 * ```
 */
export declare const encrypt: (private_key: PrivateKey, public_key: PublicKey, message: Uint8Array, nonce?: string | bigint) => {
    nonce: bigint;
    message: Uint8Array;
    checksum: number;
};
/**
 * Decrypts a binary memo payload with Hive memo key agreement.
 *
 * @param private_key - Recipient or sender memo private key.
 * @param public_key - Counterparty memo public key.
 * @param nonce - Memo nonce from the encrypted envelope.
 * @param message - Ciphertext bytes.
 * @param checksum - Shared-secret checksum from the encrypted envelope.
 * @returns Decrypted memo bytes.
 *
 * @throws Error
 * Thrown when the checksum does not match the derived shared secret.
 *
 * @example
 * ```ts
 * const plaintext = decrypt(memoKey, otherMemoPublicKey, nonce, encrypted, check)
 * ```
 */
export declare const decrypt: (private_key: PrivateKey, public_key: PublicKey, nonce: string | bigint, message: Uint8Array, checksum: number) => Uint8Array;