export interface Keypair {
    publicKeyHex: string;
    secretKeyHex: string;
}
export declare function generateKeypair(): Keypair;
export declare function publicKeyToAccountId(publicKeyHex: string): string;
export declare function accountIdToPublicKey(accountId: string): string;
/** @deprecated use accountIdToPublicKey */
export declare const agentIdToPublicKey: typeof accountIdToPublicKey;
export interface CapabilityTokenOptions {
    sub: string;
    iss: string;
    perm: string[];
    exp?: number;
    aud?: string;
}
export declare function sign(data: Buffer, secretKeyHex: string): Buffer;
export declare function signPayload(payload: Record<string, unknown>, secretKeyHex: string): string;
export declare function createCapabilityToken(opts: CapabilityTokenOptions, secretKeyHex: string): string;