React Native

RSA Sign utf-8 Bytes of String to get Base64 RSA Signature

See more Apple Keychain Examples

Demonstrates how RSA sign the utf-8 byte representation of a string to get the signature in base64 format. React Native

import { Cert, Rsa, StringBuilder } from '@chilkat/react-native'

function chilkatExample() {
  // Assuming the smartcard/USB token is installed with the correct drivers from the manufacturer,
  // this code can work on multiple platforms including Windows, MacOS, Linux, and iOS.

  // Chilkat automatically detects and determines the way in which the HSM is used,
  // which can be by PKCS11, Apple Keychain, Microsoft CNG / Crypto API, or ScMinidriver.

  const cert = new Cert();

  // Set the token/smartcard PIN prior to loading.
  cert.smartCardPin = '123456';

  // Specify the certificate by its common name.
  try {
    cert.loadFromSmartcard('cn=chilkat-rsa-2048');
  } catch {
    console.log(cert.lastErrorText);
    return;
  }

  console.log(`Signing with cert: ${cert.subjectCN}`);

  // Create a string to be hashed and signed.
  const sb = new StringBuilder();
  const crlfLineEnding = true;
  for (let i = 0; i <= 10; i++) {
    sb.appendLine('This is a test.', crlfLineEnding);
  }

  const rsa = new Rsa();

  // Use the certificate's private key for signing.
  try {
    rsa.setX509Cert(cert, true);
  } catch {
    console.log(rsa.lastErrorText);
    return;
  }

  // Sign the SHA-256 hash of the utf-8 byte representation of the contents of sb
  // Return the signature in base64 format.
  rsa.encodingMode = 'base64';
  rsa.charset = 'utf-8';
  const stringToSign = sb.getAsString();
  let sigBase64: string;
  try {
    sigBase64 = rsa.signStringENC(stringToSign, 'sha256');
  } catch {
    console.log(rsa.lastErrorText);
    return;
  }

  console.log(`RSA signature as base64: ${sigBase64}`);
}