docs: public boolean checkIfSignerAlreadyExistsInTrustStore(X509Certificate signer, KeyStore trustStore) {
          if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled())
              Tr.entry(tc, "checkIfSignerAlreadyExistsInTrustStore");
  
          try {
              String signerMD5Digest = generateDigest("MD5", signer);
              if (signerMD5Digest == null) {
                  if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled())
                      Tr.exit(tc, "checkIfSignerAlreadyExistsInTrustStore -> false (could not generate digest)");
                  return false;
              }
  
              Enumeration<String> aliases = trustStore.aliases();
  
              while (aliases.hasMoreElements()) {
                  String alias = aliases.nextElement();
  
                  if (trustStore.containsAlias(alias)) {
                      X509Certificate cert = (X509Certificate) trustStore.getCertificate(alias);
  
                      String certMD5Digest = generateDigest("MD5", cert);
  
                      if (signerMD5Digest.equals(certMD5Digest)) {
                          if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled())
                              Tr.exit(tc, "checkIfSignerAlreadyExistsInTrustStore -> true (digest matches)");
                          return true;
                      }
                  }
              }
          } catch (Exception e) {
              FFDCFilter.processException(e, getClass().getName(), "checkIfSignerAlreadyExistsInTrustStore", this);
              if (TraceComponent.isAnyTracingEnabled() && tc.isDebugEnabled())
                  Tr.debug(tc, "Exception checking if signer already exists; " + e);
          }
  
          if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled())
              Tr.exit(tc, "checkIfSignerAlreadyExistsInTrustStore -> false (no digest matches)");
          return false;
      }