/**
 * Bytes {@link seal} adds to a plaintext: version byte, salt, nonce and tag. Attachment records
 * (cloud/journal.ts) are judged by `plaintext + SEAL_OVERHEAD`: a change of the AEAD envelope must
 * also bump the attachment context (`attachment/v1`), so old and new clients never read each
 * other's good records as the wrong size and clear them.
 */
export declare const SEAL_OVERHEAD: number;
export declare class DecryptError extends Error {
    constructor(message?: string);
}
export declare const randomKey: () => Buffer;
/** Derive a named key from a parent key (no salt). Examples: home-stream, verifier. */
export declare function deriveKey(parent: Uint8Array, purpose: string): Buffer;
/** AEAD-encrypt `plaintext` under `key`, bound to `context` (AAD) and `purpose` (HKDF info). */
export declare function seal(key: Uint8Array, plaintext: Uint8Array, purpose: string, context: string): Buffer;
export declare function open(key: Uint8Array, envelope: Uint8Array, purpose: string, context: string): Buffer;
export interface KeyPair {
    publicKey: Buffer;
    privateKey: Buffer;
}
export declare function generateX25519(): KeyPair;
/** Encrypt to a recipient's X25519 public key. Only the holder of the private key can open it. */
export declare function sealTo(recipientPublic: Uint8Array, plaintext: Uint8Array, context: string): Buffer;
export declare function openSealed(recipient: KeyPair, sealed: Uint8Array, context: string): Buffer;
export declare function generateEd25519(): KeyPair;
export declare function signEd25519(kp: KeyPair, message: Uint8Array): Buffer;
export declare function verifyEd25519(publicKey: Uint8Array, message: Uint8Array, signature: Uint8Array): boolean;
export interface KdfParams {
    algorithm: 'argon2id';
    memoryKiB: number;
    iterations: number;
    parallelism: number;
    salt: string;
}
export declare const DEFAULT_KDF: {
    readonly memoryKiB: 65536;
    readonly iterations: 3;
    readonly parallelism: 1;
};
export declare function newKdfParams(): KdfParams;
/**
 * Refuse KDF parameters outside KDF_LIMITS. They come from the server, which must not be able to weaken
 * the passphrase stretch or make the client allocate unbounded memory.
 */
export declare function checkKdfParams(p: KdfParams): void;
export declare function passphraseKey(passphrase: string, p: KdfParams): Promise<Buffer>;
export declare function encodeRecoveryKey(key: Uint8Array): string;
export declare function decodeRecoveryKey(text: string): Buffer;
export declare function constantTimeEqual(a: Uint8Array, b: Uint8Array): boolean;
export declare const sha256Hex: (b: Uint8Array) => string;
export declare const hmacSha256: (key: Uint8Array, message: Uint8Array) => Buffer;
export { uuidv7 } from './uuidv7.js';
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