code: @Beta
    public final X509Certificate verifySignature() throws GeneralSecurityException {
      X509TrustManager trustManager = getDefaultX509TrustManager();
      if (trustManager == null) {
        return null;
      }
      return verifySignature(trustManager);
    }
docs: {@link Beta} <br>
  Verifies the signature of the content using the certificate chain embedded in the signature.
  
  <p>Currently only {@code "RS256"} algorithm is verified, but others may be added in the future.
  For any other algorithm it returns {@code null}.
  
  <p>The certificate chain is verified using the system default trust manager.
  
  <p>The leaf certificate of the certificate chain must be an SSL server certificate.
  
  @return The signature certificate if the signature could be verified, null otherwise.
  @throws GeneralSecurityException
  @since 1.19.1.