[aguahombre]

Sorry, I don't anything in the above post in conflict with what Gnasher stated, or falling into a grey area.

Lavinthal or odd-even (first discard) are knowable to declarer.
A reversal of signalling methods based on the total number of cards we now hold jointly in two suits is knowable to declarer; but playing (say) high-low to show an even number of black cards is a signal GIVING information to partner, not BASED on a key known to partner. You must disclose the same information to declarer.

Whether the methods are legal in a jurisdiction might be a different matter; but using Gnasher's definition to determine if they are encrypted is easy.

[Cthulhu D]

Let's say I always have the agreement that high-low shows an even number of black cards, low-high shows and odd number of black cards even when I don't have count via the auction.

Is that signalling arrangement an encrypted signal? Does that agreement become an encrypted signal if the auction gives us exact count on declarer's hand?

I really have no idea - I thought that an encrypted signal was an agreement based on infomation not availible to declarer (such as 'the number of boards we have played today' or 'the number of boards we have played today since someone asked us what our signalling arrangement was')

[Quartic]

A good example of a variety of ways encryption can be used in bridge can be found here. It includes encrypted bidding as well as encrypted signals.

[32519]

 Quartic, on 2012-January-15, 23:54, said:

A good example of a variety of ways encryption can be used in bridge can be found here. It includes encrypted bidding as well as encrypted signals.

Absolutely brilliant article, just loved it!

[spaderaise]

 aguahombre, on 2012-January-15, 20:02, said:

Sorry, I don't anything in the above post in conflict with what Gnasher stated, or falling into a grey area.

Lavinthal or odd-even (first discard) are knowable to declarer.

In the example I gave, partner knows my exact heart holding, and so knows whether the H6 is high or low. Declarer does not know my holding and does not know whether the H6 is high or low. The meaning of this signal depends completely on the information of my heart holding, which is known to partner and not to declarer. In what way does this not fall under the definition of "encrypted"?

 aguahombre, on 2012-January-15, 20:02, said:

A reversal of signalling methods based on the total number of cards we now hold jointly in two suits is knowable to declarer; but playing (say) high-low to show an even number of black cards is a signal GIVING information to partner, not BASED on a key known to partner. You must disclose the same information to declarer.

[...] using Gnasher's definition to determine if they are encrypted is easy.

OK then, so are methods 2(a) and 2(b) that I described in my post encrypted or not? (In each case the entire agreement is disclosed to declarer, just as written).

[spaderaise]

 Quartic, on 2012-January-15, 23:54, said:

A good example of a variety of ways encryption can be used in bridge can be found here. It includes encrypted bidding as well as encrypted signals.

If you enjoyed this, you should definitely get hold of the book written last year by the same author: Bridge at the Enigma Club. Highly recommended!

By the way, the article above is not representative of Peter Winkler's style of writing - it is an English translation of a Dutch translation of his original article....

[Zelandakh]

 spaderaise, on 2012-January-16, 05:25, said:

In the example I gave, partner knows my exact heart holding, and so knows whether the H6 is high or low. Declarer does not know my holding and does not know whether the H6 is high or low. The meaning of this signal depends completely on the information of my heart holding, which is known to partner and not to declarer. In what way does this not fall under the definition of "encrypted"?


OK then, so are methods 2(a) and 2(b) that I described in my post encrypted or not? (In each case the entire agreement is disclosed to declarer, just as written).

You are misunderstanding I think. Say that you might hold heart spots of 7652 or 762. You could play that if you hold the ♥5 you play normal suit preference, so 7 for diamonds, 2 for clubs, 6 for no preference, but if you do not hold this card you play revolving, 7 for clubs, 2 for no preference, 6 for diamonds. This would be an encrypted signal since the coding is different depending on a key (who holds the 5). But if you play that a middle high card is diamonds and a low card is clubs (always) but make these cards difficult to read that is ok, so 6 for diamonds, 5 for clubs. Declarer may not be able to immediately tell if the card is high or low but (s)he knows what the coding is. The coding is not dependant on something extraneous.

[FrancesHinden]

 spaderaise, on 2012-January-16, 05:25, said:

In the example I gave, partner knows my exact heart holding, and so knows whether the H6 is high or low. Declarer does not know my holding and does not know whether the H6 is high or low. The meaning of this signal depends completely on the information of my heart holding, which is known to partner and not to declarer. In what way does this not fall under the definition of "encrypted"?.

 Zelandakh, on 2012-January-16, 09:49, said:

You are misunderstanding I think. Say that you might hold heart spots of 7652 or 762. You could play that if you hold the ♥5 you play normal suit preference, so 7 for diamonds, 2 for clubs, 6 for no preference, but if you do not hold this card you play revolving, 7 for clubs, 2 for no preference, 6 for diamonds. This would be an encrypted signal since the coding is different depending on a key (who holds the 5). But if you play that a middle high card is diamonds and a low card is clubs (always) but make these cards difficult to read that is ok, so 6 for diamonds, 5 for clubs. Declarer may not be able to immediately tell if the card is high or low but (s)he knows what the coding is. The coding is not dependant on something extraneous.

I agree that the definition is extremely fuzzy.
I think the important part in the definition is that it's encrypted if the key is 'in principle' not available to declarer.

So to take Zelandakh's signalling method, that is not encrypted, because it's quite possible that declarer holds the ♥5 and knows what your suit preference signal means but that your partner doesn't.

To take spaderaise's example above: if I have a general agreement that 'high' means one thing and 'low' means another, then it's possible that declarer may have more information about the suit than the defence; in the case when declarer is void in the suit he doesn't, but that's an attribute of that specific hand, not about the signal as a matter of principle. If you extend this example then any meaning given to 'high' or 'low' when declarer is short in the suit is encrypted and now I can't play normal attitude signals if declarer can't read them!

[EricK]

What about the method given by Cthulhu D where your signal shows the combined count of two suits? eg On partner's opening lead, your initial count signal is high if you have an even number of "that suit plus trumps", low if odd. The signal is always entirely dependant on just the hand you hold, but partner has a much better chance of reading it than declarer - and it is in practice equivalent to an encrypted signal if declarer's exact trump length is known at outset.