React Native

Get an S/MIME Signing Time

Demonstrates the Chilkat Mime.GetSignatureSigningTimeStr method, which returns the CMS signingTime attribute for the signer at a zero-based index, as an RFC 822-style date string in GMT. The only argument is the signer index.

Note: The file paths are relative to the application's current working directory. Absolute paths may also be used. Supply the paths appropriate to your own environment.

Background: This is the timestamp the signer asserted at signing — useful for "when was this signed" audit trails and for evaluating whether the signing certificate was valid at that moment. Because it is a signed attribute, it is tamper-evident. Guard the call with HasSignatureSigningTime, since the attribute is optional. Note it is the signer's claim, not a trusted third-party timestamp.

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React Native

import { Mime } from '@chilkat/react-native'

function chilkatExample() {
  const mime = new Mime();
  try {
    mime.loadMimeFile('qa_data/signed.eml');
  } catch {
    console.log(mime.lastErrorText);
    return;
  }

  // After verifying, get the CMS signingTime for each signer that has one, as an RFC 822 date string
  // in GMT.  The only argument is the zero-based signer index.
  try {
    mime.verify();
  } catch {
    console.log(mime.lastErrorText);
    return;
  }

  const n = mime.numSignerCerts;
  for (let i = 0; i < n; i++) {
    // Only signers that included a signing time have one to retrieve.
    if (mime.hasSignatureSigningTime(i)) {
      let signingTime: string;
      try {
        signingTime = mime.getSignatureSigningTimeStr(i);
      } catch {
        console.log(mime.lastErrorText);
        return;
      }

      console.log(`Signer ${i} signing time: ${signingTime}`);
    }
  }
}