code: public void delete(String name) throws IOException {
          if (name.equalsIgnoreCase(DIGITAL_SIGNATURE)) {
              set(0,false);
          } else if (name.equalsIgnoreCase(NON_REPUDIATION)) {
              set(1,false);
          } else if (name.equalsIgnoreCase(KEY_ENCIPHERMENT)) {
              set(2,false);
          } else if (name.equalsIgnoreCase(DATA_ENCIPHERMENT)) {
              set(3,false);
          } else if (name.equalsIgnoreCase(KEY_AGREEMENT)) {
              set(4,false);
          } else if (name.equalsIgnoreCase(KEY_CERTSIGN)) {
              set(5,false);
          } else if (name.equalsIgnoreCase(CRL_SIGN)) {
              set(6,false);
          } else if (name.equalsIgnoreCase(ENCIPHER_ONLY)) {
              set(7,false);
          } else if (name.equalsIgnoreCase(DECIPHER_ONLY)) {
              set(8,false);
          } else {
            throw new IOException("Attribute name not recognized by"
                                  + " CertAttrSet:KeyUsage.");
          }
          encodeThis();
      }
docs: Delete the attribute value.