/**
 * Sign command payload definition.
 */
type Sign = {
    /**
     * Currently the only datasource supported is "clipboard".
     */
    datasource?: 'clipboard';
    /**
     * The text to be signed. Must be properly URL escaped.
     */
    text?: string;
    /**
     * The 8 character KeyID of the private key that you wish to use to sign the data.
     * If the KeyID is not currently in the iPGMail keychain, the operation will fail.
     */
    signkey?: string;
    /**
     * Direct the resulting PGP armor text to a file or the clipboard.
     * If this option is not present, the result is still sent back to the caller in the x-success callback.
     */
    result?: 'clipboard' | string;
};
/**
 * Sign a block of plaintext and either save it to a file or return it to the requesting app in the x-success callback.
 *
 * @param payload Sign command payload.
 * @returns iPGMail sign URL.
 * @example
 * sign({
 *   datasource: 'clipboard',
 *   signkey: '47E3234C',
 *   result: 'clipboard',
 * })
 * // => 'x-ipgmail://x-callback-url/sign?datasource=clipboard&signkey=47E3234C&result=clipboard'
 * @example
 * sign({
 *   text: 'This is a test...',
 * })
 * // => 'x-ipgmail://x-callback-url/sign?text=This%20is%20a%20test...'
 * @example
 * sign({
 *   datasource: 'clipboard',
 *   signkey: '47E3234C',
 *   result: 'savefile.sig',
 * })
 * // => 'x-ipgmail://x-callback-url/sign?datasource=clipboard&signkey=47E3234C&result=savefile.sig'
 * @link https://ipgmail.com/developers/
 */
export declare function sign(payload?: Sign): string;
export {};