private WSSecBase doEncryption(
      TokenWrapper recToken,
      SecurityToken encrTok,
      boolean attached,
      List<WSEncryptionPart> encrParts,
      boolean atEnd) {
    // Do encryption
    if (recToken != null && recToken.getToken() != null && encrParts.size() > 0) {
      Token encrToken = recToken.getToken();
      policyAsserted(recToken);
      policyAsserted(encrToken);
      AlgorithmSuite algorithmSuite = sbinding.getAlgorithmSuite();
      if (encrToken.isDerivedKeys()) {
        return doEncryptionDerived(recToken, encrTok, encrToken, attached, encrParts, atEnd);
      } else {
        try {
          WSSecEncrypt encr = new WSSecEncrypt(wssConfig);
          String encrTokId = encrTok.getId();
          if (attached) {
            encrTokId = encrTok.getWsuId();
            if (encrTokId == null
                && (encrToken instanceof SecureConversationToken
                    || encrToken instanceof SecurityContextToken)) {
              encr.setEncKeyIdDirectId(true);
              encrTokId = encrTok.getId();
            } else if (encrTokId == null) {
              encrTokId = encrTok.getId();
            }
            if (encrTokId.startsWith("#")) {
              encrTokId = encrTokId.substring(1);
            }
          } else {
            encr.setEncKeyIdDirectId(true);
          }
          if (encrTok.getTokenType() != null) {
            encr.setCustomReferenceValue(encrTok.getTokenType());
          }
          encr.setEncKeyId(encrTokId);
          encr.setEphemeralKey(encrTok.getSecret());
          Crypto crypto = getEncryptionCrypto(recToken);
          if (crypto != null) {
            this.message.getExchange().put(SecurityConstants.ENCRYPT_CRYPTO, crypto);
            setEncryptionUser(encr, recToken, false, crypto);
          }

          encr.setDocument(saaj.getSOAPPart());
          encr.setEncryptSymmKey(false);
          encr.setSymmetricEncAlgorithm(algorithmSuite.getEncryption());

          if (encrToken instanceof IssuedToken || encrToken instanceof SpnegoContextToken) {
            // Setting the AttachedReference or the UnattachedReference according to the flag
            Element ref;
            if (attached) {
              ref = encrTok.getAttachedReference();
            } else {
              ref = encrTok.getUnattachedReference();
            }

            String tokenType = encrTok.getTokenType();
            if (ref != null) {
              SecurityTokenReference secRef = new SecurityTokenReference(cloneElement(ref), false);
              encr.setSecurityTokenReference(secRef);
            } else if (WSConstants.WSS_SAML_TOKEN_TYPE.equals(tokenType)
                || WSConstants.SAML_NS.equals(tokenType)) {
              encr.setCustomReferenceValue(WSConstants.WSS_SAML_KI_VALUE_TYPE);
              encr.setKeyIdentifierType(WSConstants.CUSTOM_KEY_IDENTIFIER);
            } else if (WSConstants.WSS_SAML2_TOKEN_TYPE.equals(tokenType)
                || WSConstants.SAML2_NS.equals(tokenType)) {
              encr.setCustomReferenceValue(WSConstants.WSS_SAML2_KI_VALUE_TYPE);
              encr.setKeyIdentifierType(WSConstants.CUSTOM_KEY_IDENTIFIER);
            } else {
              encr.setCustomReferenceValue(tokenType);
              encr.setKeyIdentifierType(WSConstants.CUSTOM_KEY_IDENTIFIER);
            }
          } else if (encrToken instanceof UsernameToken) {
            encr.setCustomReferenceValue(WSConstants.WSS_USERNAME_TOKEN_VALUE_TYPE);
          } else if (!isRequestor()) {
            if (encrTok.getSHA1() != null) {
              encr.setCustomReferenceValue(encrTok.getSHA1());
              encr.setKeyIdentifierType(WSConstants.ENCRYPTED_KEY_SHA1_IDENTIFIER);
            } else {
              encr.setKeyIdentifierType(WSConstants.EMBED_SECURITY_TOKEN_REF);
            }
          }

          encr.prepare(saaj.getSOAPPart(), crypto);

          if (encr.getBSTTokenId() != null) {
            encr.prependBSTElementToHeader(secHeader);
          }

          Element refList = encr.encryptForRef(null, encrParts);
          if (atEnd) {
            this.insertBeforeBottomUp(refList);
          } else {
            this.addDerivedKeyElement(refList);
          }
          return encr;
        } catch (WSSecurityException e) {
          policyNotAsserted(recToken, e);
        }
      }
    }
    return null;
  }