第三方应用怎么获取应用签名证书的hash值

import bundleManager from '@ohos.bundle.bundleManager'; 
import { BusinessError } from '@ohos.base'; 
import hilog from '@ohos.hilog'; 
let bundleFlags = bundleManager.BundleFlag.GET_BUNDLE_INFO_DEFAULT; 
try { 
    bundleManager.getBundleInfoForSelf(bundleFlags).then((data) => { 
        hilog.info(0x0000, 'testTag', 'getBundleInfoForSelf successfully. Data: %{public}s', JSON.stringify(data)); 
    //data里可以获取到signatureInfo，即应用的签名证书信息 
    }).catch((err: BusinessError) => { 
        hilog.error(0x0000, 'testTag', 'getBundleInfoForSelf failed. Cause: %{public}s', err.message); 
    }); 
} catch (err) { 
    let message = (err as BusinessError).message; 
    hilog.error(0x0000, 'testTag', 'getBundleInfoForSelf failed: %{public}s', message); 
}

let filePath = pathDir + "/test.txt"; 
Hash.hash(filePath, "sha256").then((str: string) => { 
  console.info("calculate file hash succeed:" + str); 
}).catch((err: BusinessError) => { 
  console.info("calculate file hash failed with error message: " + err.message + ", error code: " + err.code); 
});