Talk:International Data Encryption Algorithm

message: It's late and I'm tired, but this article lacks information on (a) the input/output transformation stage, and (b) the subkey generator. →Raul654 03:19, Mar 21, 2004 (UTC)
: True, but they aren't very interesting... Matt 03:36, 21 Mar 2004 (UTC)
replies: text:  I'll add them to the to-do list anyway. — Matt 23:24, 27 Nov 2004 (UTC)
replies: text:  I have added an image showing the transformation round. danielap48 02:04, 19 Oct 2006 (UTC)
thread_title:  TODO list (now done!) 

message: Can someone please edit the image to make it clear when paths cross over, perhaps with the little bridges seen on wiring diagrams? Pimantony 19:41, 27 March 2006 (UTC)
thread_title: Diagram

message: The key schedule is incorrectly described. The 25 bit left rotate is not applied to the 128 bit key until after the full 128 bits are used in the key. This happens in the middle of the second round (96 bits are used for the first round, the remaining 32 bits are used in the second round.) The rotate left operation is only performed a total of 6 times in the key schedule.  —Preceding unsigned comment added by 216.83.134.34 (talk) 03:35, 21 June 2008 (UTC)
thread_title: Incorrect Key Schedule description

message: The IDEA applet link does not appear too useful, not in English and I saw no way to run a simulation.--Billymac00 (talk) 19:24, 4 January 2009 (UTC)
thread_title:  External Link  

message: Here's an explanation of the US patent expiration for .  I acknowledge this constitutes original research; I offer it not as a source, but rather to explain why we should have confidence that the 2012 expiration date does not apply.  I am a U.S. patent attorney, but why should you believe that?
===Statutes and relevant (and not-so-relevant) dates===
Here's what we're going to look at:
* The front page of the patent, ;
* The following provisions of the U.S. patent code, codified at 35. U.S.C.:
** - the basic statute covering term.  We'll be looking at 154(c) and 154(a) -- specifically 154(a)(2) and 154(a(3).
**, benefit of earlier filing date.
**, benefit of earlier filing date in the United States.
**, divisional applications.
**, PCT applications.
**, definitions relating to PCT applications.
Now, here are the interesting dates to note, from the face of the patent:
* 1990-05-18: Initial Swiss patent application no. 01690/90 is filed.
* 1991-05-16: Patent Cooperation Treaty (PCT) application (pub. no. WO90/12452) is filed.
* 1992-01-07: PCT application enters "national stage" in the United States
* 1993-05-25: U.S. Patent no. 5,214,703 issues.
===Analysis===
The article at present states, incorrectly:
:(According to the PGP FAQ[7], the US patent expired on May 25, 2010. However, US patent law was changed in 1995 such that patents now expire 20 years after filing, not 17 years after issuing. This holds retroactively for all patents that had not yet expired at the time the changed law came into effect,[8] and it thus holds for IDEA. International treaties may or may not cause expiry as early as May 16, 2011.[9])
The italicized portion is a slight oversimplification, although harmless here, since it ends up in the same place.  Section 154(a) is the provision that generally covers patent term, and yes, it was changed in 1995 (actually, it was changed December 8, 1994 with the passage of the Uruguay Round Agreements Act; becoming effective for our purposes six months later, on June 8, 1995).  However, it is not retroactive, as such, to pre-June 8, 1995 patents and applications.  Rather, the term of those patents and applications are governed by § 154(c).  That section says:
:The term of a patent that is in force on or that results from an application filed before the date that is 6 months after the date of the enactment of the Uruguay Round Agreements Act [i.e., June 8, 1995] shall be the greater of the 20-year term as provided in subsection (a), or 17 years from grant, subject to any terminal disclaimers.
In other words, the 20-year-from-filing "new rule" is not applied retroactively as the article states; rather a new hybrid rule applies to these patents: they get either the term under the "old rule" (issue + 17 years) or the "new rule" (filing + 20 years), whichever is longer.  So it's not simple retroactivity.
The term under the old rule would have been May 25, 1993 + 17 years = May 25, 2010.  We'll see later that this is the lesser of the two and won't matter, but let's put that aside for a moment.
Now, all we have to figure out is 20 years from the filing date.  But the question is: which of the three "filing dates" is used?  I'll go to the statute in a moment, but the basic principle (just in case you want to make sense of this) is that the filing date that first asserts rights under U.S. patent law is the one that's used.  This is true even if the prosecution of the application, where the examiner compares the claimed invention to the prior art to determine whether a patent should issue, honors an earlier filing date to determine whether art is "prior art" or not.
Section 154(a)(2) says applications filed under sections 120, 121, and 365(c) count.  Section 154(a)(3) says that applications filed under sections 119, 365(a) and 365(b) do not.  We'll do the 154(a)(2) set first and then the 154(a)(2) set.
Sections 120 and 121 are not at issue here.  These sections cover prior U.S. applications that describe the same invention.  They're essentially the same thing.  Section 120 is directed at a prior application that either resulted in a patent, and then continued to be processed in a second application to get additional claims, or a prior application that did not result in a patent, and was refiled to continue prosecution.  Section 121 is directed at an application that the Patent and Trademark Office (PTO) determined contained two or more distinct inventions, and so required that the application be divided into multiple applications.  In either case, the idea is that the invention was described in an earlier U.S. patent application.  None of the applications at issue here are 120 or 121 applications.
Section 365(c) refers to a PCT application (called an "international application" in the statutory text; that's defined in section 351) that designates the United States.  That's exactly what we have here: the 1991-05-16 PCT application.  We know it designated the U.S., because it ended up as a U.S. patent.  So, for the moment, our working filing date is 1991-05-16.  Again, the principle at work here is that this is a patent application that, if maturing to a patent, would assert U.S. rights.
We can ignore the national stage 1992-01-07 date.  This is the date the PCT application turns into what is effectively a regular U.S. application.  If there was no prior PCT application, just a regular patent application, this is the date that would be used; but due to 365(c), the PCT application date is used instead.
Okay, so based on 154(a)(2), 1992-01-07 is the filing date.  But now let's discuss those the other sections, which 154(a)(3) say do not count: 119, 365(a) and 365(b).
Section 119 covers the case where a non-PCT application is made in a foreign country.  U.S. patent law allows you to file a U.S. patent application, claiming priority from an earlier non-US application.  Rather than filing a PCT application, Ascom could have filed a U.S. application, claiming priority from this Swiss application.  In that case, the Swiss application would have been a § 119 application.  It would have been used to determine what is and is not prior art, but would not have been used to start the patent term clock (because that application, unlike the PCT did not claim any U.S. rights; that would not have occurred until Ascom filed its U.S. application).
So the Swiss patent application is somewhat like, but not quite, a 119 application.  It doesn't qualify as a 119 application, because the U.S. patent is not based on a U.S. application that claims priority to the Swiss application.  Instead, the U.S. patent is based on a national-stage patent application, which derives from the PCT application, which derives from the Swiss application.  In any event, even if it were a 119 application, it doesn't enter into determining the term; § 154(a)(3) says to ignore it.  So, the 1990-05-18 date can be ignored.
Sections 365(a) and 365(b) are essentially the PCT equivalents of 119.  365(a) essentially covers a PCT application that designates a non-US country.  This can be treated effectively like a 119 application: a regular U.S. application can be filed based on it, just as with a 119 application, and the 365(a) application will be used to determine priority date; but it will not start the 20-year term.
365(b) essentially covers a PCT application that does designate the U.S., and that relies on an earlier non-US filing date.  That's what we have here.  The 1991 PCT application claims priority from the 1990 Swiss application.  In this case, the Swiss date will be used as the priority date, but not to compute the patent term.  It's a little odd, because the PCT application comes in under both 365(b) and 365(c).  What this means is that, per 365(b), the Swiss application will be used for priority, but because of 154(a)(3) will not be used to compute patent term; however, per 365(c), the PCT application itself will be used to compute the term, because of 154(a)(2).
===Conclusion===
So the upshot is: the filing date used to compute the term is the PCT filing date, 1991-05-16.  That means the patent expires on the later of the following two dates:
* Filing date (1991-05-16) + 20 years, or 2011-05-16
* Issue date (1993-05-25) + 17 years, or 2010-05-25
The later of these two dates is 2011-05-16; and that's the expiration date: May 16, 2011.
I know this is kind of muddy, but I hope it cuts through some of the confusion in the discussion above, and the 2012 date does not apply.  Although some of the sources say 2010 (erroneously) it's clearly not 2012. TJRC (talk) 00:00, 7 July 2011 (UTC)
replies: text: The overwhelming majority of all people reading this article will do it from a very practical perspective: They want to know after what date IDEA can safely be used without the fear of patent infringement. They don't read it for theoretical purposes about what interactions of what laws might cause exceptions. And from this perspective, the article states (correctly, it may be added) that IDEA is safe to use after January 7, 2012: it is "expiring not later than January 7, 2012". It doesn't deny it may be legal to use it before that date, but this question has not been discussed before except for what has been written above. The article acknowledges that "expiry [may take place] as early as May 16, 2011", but, as you admit yourself, this "constitutes original research". You present a complex and long analysis above to support this claim. Such analyses are sometimes wrong (in less obvious places)—without any bad intent. The world is a complicated thing. Even for a U.S. patent attorney. ;) I hope we can agree that the article presents the situation in a fair manner. Repeating your arguments in the article, in addition to what is said already, would give it undue weight. --rtc (talk) 17:31, 6 August 2011 (UTC)
thread_title: Explanation of U.S. patent expiration

message: So the upshot is: the filing date used to compute the term is the PCT filing date, 1991-05-16.  That means the patent expires on the later of the following two dates:
* Filing date (1991-05-16) + 20 years, or 2011-05-16
* Issue date (1993-05-25) + 17 years, or 2010-05-25
The later of these two dates is 2011-05-16; and that's the expiration date: May 16, 2011.
I know this is kind of muddy, but I hope it cuts through some of the confusion in the discussion above, and the 2012 date does not apply.  Although some of the sources say 2010 (erroneously) it's clearly not 2012. TJRC (talk) 00:00, 7 July 2011 (UTC)
replies: text: The overwhelming majority of all people reading this article will do it from a very practical perspective: They want to know after what date IDEA can safely be used without the fear of patent infringement. They don't read it for theoretical purposes about what interactions of what laws might cause exceptions. And from this perspective, the article states (correctly, it may be added) that IDEA is safe to use after January 7, 2012: it is "expiring not later than January 7, 2012". It doesn't deny it may be legal to use it before that date, but this question has not been discussed before except for what has been written above. The article acknowledges that "expiry [may take place] as early as May 16, 2011", but, as you admit yourself, this "constitutes original research". You present a complex and long analysis above to support this claim. Such analyses are sometimes wrong (in less obvious places)—without any bad intent. The world is a complicated thing. Even for a U.S. patent attorney. ;) I hope we can agree that the article presents the situation in a fair manner. Repeating your arguments in the article, in addition to what is said already, would give it undue weight. --rtc (talk) 17:31, 6 August 2011 (UTC)
thread_title: Conclusion

message: As others have noted, this article really needs to update the current patent situation. It's quite certain that the US patent has expired, but I hope someone is able to find a good source for the other patents granted.
MMcCallister (talk) 16:30, 23 August 2012 (UTC)
thread_title:  Patent Situation in 2012 

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