type Base64URLString = string;
export declare function encrypt(secret: string, plaintext: string): Promise<string>;
/**
 * Decrypts base64 ciphertext with a symmetric key derived from a hex shared secret.
 * @param secret Hex-encoded shared secret.
 * @param ciphertext Base64 ciphertext to decrypt.
 * @returns Decrypted UTF-8 plaintext.
 */
export declare function decrypt(secret: string, ciphertext: Base64URLString | string): Promise<string>;
/**
 * Computes an X448 shared secret from local and peer key material.
 * @param ownPrivateKey Local private key in raw/base64/base64url or PKCS#8-wrapped form.
 * @param ownPublicKey Local public key in raw/base64/base64url or SPKI-wrapped form.
 * @param otherPublicKey Peer public key in raw/base64/base64url or SPKI-wrapped form.
 * @returns Hex-encoded shared secret, or a failure message when key material is missing/invalid.
 */
export declare function getSharedSecret(ownPrivateKey: string, ownPublicKey: string, otherPublicKey: string): Promise<string>;
export {};