Lotus 123 ("fortunately" for you - unfortunately for those of us who have been wanting Lotus Corp to plug this loophole) has a longstanding BUG which effectively "opens the backdoor" to practically all 123 protected spreadsheets. This is accomplished by using the FILE COMBINE COMMAND. First, create a NEW file and create ample sheets (try 50) - to accommodate the sheets which you will then FILE COMBINE from the protected file. (If you happen to know the number of sheets in the protected file, you could simply create that same number of sheets in your new file). Formatting does NOT get FILE COMBINED. However, the file-combined data will often contain the PASSWORD in the macro code, in which case you can then gain access to the entire ORIGINAL file. ...hope this helps.
Footnote:
If Lotus Corp is "listening", it would be nice to see them finally address this "backdoor" issue. And, it would be great if they would recognize the extreme power of their "MACRO&