import { EncryptedBrainFile } from '../types.js';
export declare class BrainEncryption {
    /** Derive a 32-byte key from a passphrase + salt (scrypt). */
    static deriveKey(passphrase: string, salt: Buffer): Buffer;
    /** Encrypt plaintext bytes with a passphrase. Returns a JSON-friendly structure. */
    static encrypt(plaintext: string | Buffer, passphrase: string): EncryptedBrainFile;
    /** Decrypt an encrypted file. Throws if passphrase is wrong or data tampered. */
    static decrypt(encrypted: EncryptedBrainFile, passphrase: string): Buffer;
    /** Encrypt a file path in-place (atomic). */
    static encryptFile(filePath: string, passphrase: string): Promise<void>;
    /** Decrypt a .enc file back to plaintext. */
    static decryptFile(encPath: string, passphrase: string, outPath?: string): Promise<string>;
}
//# sourceMappingURL=brain-encryption.d.ts.map