import type { Envelope } from './types.js';
/**
 * Raw key material. String keys are interpreted as UTF-8 bytes; callers with
 * base64 input must decode it before constructing EnvelopeSigningKey.
 */
export type EnvelopeKeyMaterial = Buffer | Uint8Array | string;
export interface EnvelopeSigningKey {
    key_id: string;
    key_version: number;
    key: EnvelopeKeyMaterial;
}
export type EnvelopeKeyLookup = (keyId: string, keyVersion: number) => EnvelopeKeyMaterial | undefined;
export declare function signEnvelope(envelope: Envelope, signingKey: EnvelopeSigningKey): Envelope;
export declare function verifyEnvelope(envelope: Envelope, lookupKey: EnvelopeKeyLookup): boolean;
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