code: public void set(String name, Object obj) throws IOException {
          if (name.equalsIgnoreCase(KEY_ID)) {
              if (!(obj instanceof KeyIdentifier)) {
                throw new IOException("Attribute value should be of" +
                                      " type KeyIdentifier.");
              }
              id = (KeyIdentifier)obj;
          } else {
            throw new IOException("Attribute name not recognized by " +
                  "CertAttrSet:SubjectKeyIdentifierExtension.");
          }
          encodeThis();
      }
docs: Set the attribute value.