code: public boolean unprotectDocument(String pwd) {
      	boolean result = false;
      	if (this.protectionHash.equals(RtfProtection.generateHash(pwd))) {
      		this.protectionLevel =  RtfProtection.LEVEL_NONE;
      		this.protectionHash = null;
      		result = true;
      	}
      	return result;
      }
docs: Author: Howard Shank (hgshank@yahoo.com)
  @param pwd Document password - clear text
  @return true if document unprotected, false if protection is not removed.
  @since 2.1.1