Enigma rotor made of PCBs

[David Griffith]

I've been toying with the idea of making a replica of the Enigma
encrypter using as much mechanical components as possible. The most
complicated parts appear to making and wiring the rotors. I suppose the
rotors could be turned by a solenoid instead of levers from the keys.

So, the rotors. How feasable is it to make an Enigma rotor from
multi-layer PCB?

--
David Griffith
davidmy...@acm.org <--- Put my last name where it belongs

[Dave Garland]

On 10/16/2015 8:47 PM, David Griffith wrote:
> I've been toying with the idea of making a replica of the Enigma
> encrypter using as much mechanical components as possible. The most
> complicated parts appear to making and wiring the rotors. I suppose the
> rotors could be turned by a solenoid instead of levers from the keys.
>
> So, the rotors. How feasable is it to make an Enigma rotor from
> multi-layer PCB?
>

The electrical part doesn't seem like it would be difficult, even with
just a 2-sided PCB. All but one of the rotors seem to be basically a
ring of 26 contact pads on each side, with arbitrary (but fixed)
interconnections between the sides. (The reflector would only need a
single-sided PCB, and jumper wires on the non-clad side.) You might
need to bring one side out to a (smaller) ring on the other side and
use jumper wires, I suspect it's not topologically possible without,
though you could probably do that by sandwiching several PCBs
together. Achieving good electrical connections between the rotors
would be interesting. Might need a divider between the rotors to hold
spring-loaded contacts to ride against the rotors, since you wouldn't
have the (presumably) spring-loaded contact pins of the original. Or
look at how (older) rotary switch contacts are made.

I'd think it would be the mechanical stuff (including getting the
contacts to the rotors to work well) that would be most challenging.

[Joe Pfeiffer]

davidmy...@acm.org (David Griffith) writes:

> I've been toying with the idea of making a replica of the Enigma
> encrypter using as much mechanical components as possible. The most
> complicated parts appear to making and wiring the rotors. I suppose the
> rotors could be turned by a solenoid instead of levers from the keys.
>
> So, the rotors. How feasable is it to make an Enigma rotor from
> multi-layer PCB?

Piece of cake; I'd have to refresh my memory, but IIRC a two-layer board
would do it easily. I'd probably do a single board design that had
contacts and would accept jumpers, and then solder on wire jumpers to
create the different rotors required.

oshpark.com is who I use to fab my very-small-quantity boards.

[Scott Lurndal]

This very closely describes various stepper wheels used in
electromechanical pinballs of the 60's and early 70's; complete
with the spring-loaded contacts.

scott

[Jon Elson]

David Griffith wrote:

> I've been toying with the idea of making a replica of the Enigma
> encrypter using as much mechanical components as possible. The most
> complicated parts appear to making and wiring the rotors. I suppose the
> rotors could be turned by a solenoid instead of levers from the keys.
>
> So, the rotors. How feasable is it to make an Enigma rotor from
> multi-layer PCB?
>

You ought to take a look at the work done by Tatjana van Vark in the
Netherlands. She built a crypto machine similar to an Enigma.

http://www.tatjavanvark.nl/tvv1/pht10.html

She also has done some AMAZING other stuff, has a working Litton inertial
measuring unit, the complete electronics suite from a Vulcan bomber is in
her dining room.

Jon

[Greymaus]

The Question: Why was the whole Enigma project kept secret so long

AFAIK, the reason was that Enigmas were produced after the war by a
Swiss company, and used bysecond level countries for what they thouht was secure
communic







--
greymaus
.
.
...

[gareth]

"Greymaus" <ma...@mail.com> wrote in message
news:slrnn2hltd...@dmaus.org...

> The Question: Why was the whole Enigma project kept secret so long
>
> AFAIK, the reason was that Enigmas were produced after the war by a
> Swiss company, and used bysecond level countries for what they thouht was
> secure
> communic

Legend has it that it was foul play by the Brits. Fearing the independence
attempts by
parts of its Empire, Brit handed over the machines to the subjugated
countries with the
assurance that it was foolproof, and, of course, not letting out that they
could read all
the resulting diplomatic traffic.

Therefore, keepingthesecret was of importance to Brit

[Michael Black]

But a lot of that was kept secret. R.V. Jones wrote "The Secret War" (I
think I have the title right) in the early seventies, he said something
like it was the earliest such details could be revealed.

I thought they honestly did worry about something new happening, and if
the old news got out, it might impact on future work. So they put a 25
year hold on it, enough time that techniques would change.

Forget about technical details, if you see the social work done on all of
those secrets, that might cause others to be more careful.

Michael

[Quadibloc]

On Thursday, October 22, 2015 at 5:38:53 AM UTC-6, Greymaus wrote:

> The Question: Why was the whole Enigma project kept secret so long

Actually, the real reason is not particularly sinister. The stansard rule, in
both the US and UK is that everything crypro is so sensitive that it is only
released after 50 years.

An exception to that was made in the case of the American solution of PURPLE in
order to respond to persistent rumors that FDR deliberately suppressed advance
knowledge of the attack on Pearl Harbor in order to get the US into the war.

John Savard

[Charlie Gibbs]

I recall hearing similar speculation about DES.

However, I suspect the reason is somewhat more prosaic. ISTR reading that
in the absence of explicit instructions, classified material automatically
bumps down one level every 10 years. This means that anything marked
"top secret" would take 50 years to go all the way down to "unclassified".

> Therefore, keepingthesecret was of importance to Brit

Uh-oh, looks like they caught up with him.

--
/~\ cgi...@kltpzyxm.invalid (Charlie Gibbs)
\ / I'm really at ac.dekanfrus if you read it the right way.
X Top-posted messages will probably be ignored. See RFC1855.
/ \ HTML will DEFINITELY be ignored. Join the ASCII ribbon campaign!

[Quadibloc]

On Thursday, October 22, 2015 at 12:22:58 PM UTC-6, Charlie Gibbs wrote:

> I recall hearing similar speculation about DES.

I do recall reading some history that suggested that the initial permutation
and inverse initial permutation, instead of being present in DES to simplify
some initially-envisaged implementation, was present to fool the NSA into
tolerating the existence of the algorithm as a government standard by making them
think that the algorithm would not be disclosed publicly.

John Savard

[78lp]

"gareth" <no....@thank.you.invalid> wrote in message
news:n0aukf$n8q$1...@dont-email.me...

The problem with that line is that before they were
independent, there was no diplomatic traffic to read.

The Mau Mau etc didn’t have diplomatic traffic with anyone.

[78lp]

"Greymaus" <ma...@mail.com> wrote in message
news:slrnn2hltd...@dmaus.org...

> On 2015-10-21, Jon Elson <el...@pico-systems.com> wrote:
>> David Griffith wrote:
>>
>>> I've been toying with the idea of making a replica of the Enigma
>>> encrypter using as much mechanical components as possible. The most
>>> complicated parts appear to making and wiring the rotors. I suppose the
>>> rotors could be turned by a solenoid instead of levers from the keys.
>>>
>>> So, the rotors. How feasable is it to make an Enigma rotor from
>>> multi-layer PCB?
>>>
>> You ought to take a look at the work done by Tatjana van Vark in the
>> Netherlands. She built a crypto machine similar to an Enigma.
>>
>> http://www.tatjavanvark.nl/tvv1/pht10.html
>>
>> She also has done some AMAZING other stuff, has a working Litton inertial
>> measuring unit, the complete electronics suite from a Vulcan bomber is in
>> her dining room.
>
>
> The Question: Why was the whole Enigma project kept secret so long

Basically because they wanted to continue to read the traffic that
others were doing after the war had ended, during the cold war.

If it had been clear what they could read, more secure communication
would have been used so they couldn’t read it.

> AFAIK, the reason was that Enigmas were produced after the war by a
> Swiss company, and used bysecond level countries for what they thouht was
> secure
> communic

Not just the physical machine, the technique used to break
is also applicable to what is used to secure communication.

And not just second level countries either, there was an
immense amount of effort that went into reading the
communications of the USSR and the soviet bloc etc.

[barry...@yahoo.com]

On Friday, October 16, 2015 at 6:50:05 PM UTC-7, David Griffith wrote:
> I've been toying with the idea of making a replica of the Enigma
> encrypter using as much mechanical components as possible. The most
> complicated parts appear to making and wiring the rotors. I suppose the
> rotors could be turned by a solenoid instead of levers from the keys.
>
> So, the rotors. How feasable is it to make an Enigma rotor from
> multi-layer PCB?

> ...

Have you seen Simon's recent work here?

http://www.asciimation.co.nz/bb/2015/10/04/bombe-completed

Mike B.

[Morten Reistad]

One tidbit here; the Queen of the UK and a score of other
nations keeps her own crypto machines jealously guarded and
the UK is not involved, except as consultants for the
secrecy.

The royals operate the cipher machines themselves, and no
servants are allowed in the room while this happens. This
is very unusual for royals; they usually have servants
doing everything for them.

The rationale is that she needs secure channels to all
her subject nations, none of which should eavesdrop on any
other.

-- mrr

[Greymaus]

On 2015-10-23, Morten Reistad <fi...@last.name.invalid> wrote:
> In article <d8tnd3...@mid.individual.net>, 78lp <78...@nospam.com> wrote:
>>
>>
>>"Greymaus" <ma...@mail.com> wrote in message
>>news:slrnn2hltd...@dmaus.org...
>>> On 2015-10-21, Jon Elson <el...@pico-systems.com> wrote:
>>>> David Griffith wrote:
>>>>
>>> The Question: Why was the whole Enigma project kept secret so long
>>
>

> One tidbit here; the Queen of the UK and a score of other
> nations keeps her own crypto machines jealously guarded and
> the UK is not involved, except as consultants for the
> secrecy.
>
> The royals operate the cipher machines themselves, and no
> servants are allowed in the room while this happens. This
> is very unusual for royals; they usually have servants
> doing everything for them.
>
> The rationale is that she needs secure channels to all
> her subject nations, none of which should eavesdrop on any
> other.

I find all that hard to believe, an 80++year woman, and her
90++ old husband?. She really has no subjects any more, the
`Commonwealth' is a group of (mosty white) countries that have gone their
seperate ways. There is supposadly an onionlke organization of countries
the the US share data, and the inner core is these countries(Canada, Australia,
New Zealand, the UK).

[Osmium]

I think he is only 90+, not 90++ :)

[gareth]

"Osmium" <r124c...@comcast.net> wrote in message
news:d8v0cn...@mid.individual.net...

>
> I think he is only 90+, not 90++ :)

But he is a peculiar object

[Osmium]

I have probably read as much as anyone on Enigma. And I *still* don't know
just how breakable it is. There are a lot of people spouting off who
shouldn't be, and I have difficulty separating what those people said from
the trustworthy people. In my mind, I guess, I think the Enigma is not very
breakable at all. To me, the most interesting question is: "Can the Enigma
be broken without cribs"? My tentative answer is "no", in other words a
workable protocol for usage can be established and the Enigma is virtually
unbreakable. Today.

BTW, my fantasy protocol includes the rule: There must be at least three
misspellings in the clear text given to the crypto guy.

[Greymaus]

In his own mind, likely 19+ :) remember the Prince Philip email hack?

(Amazingly, he was at one of the WWII early sea battles)

[Quadibloc]

On Friday, October 23, 2015 at 9:24:22 AM UTC-6, Osmium wrote:
> In my mind, I guess, I think the Enigma is not very
> breakable at all. To me, the most interesting question is: "Can the Enigma
> be broken without cribs"? My tentative answer is "no", in other words a
> workable protocol for usage can be established and the Enigma is virtually
> unbreakable. Today.

For a few short messages sent with a given set of rotor wirings, and if the
starting position of the rotors is treated as part of the key - taken from a
one-time keybook for every message - it might well be unbreakable today.

That wouldn't make it a useful cipher for practical purposes today - in any
real-world usage scenario, it would be quite breakable indeed.

John Savard

[Michael Black]

I've read some, and the impression I got was that having the machine, from
the Poles, didn't in itself solve the problem. They really did rely on
blunder, the sequence not changed the way it should have been, and
information sent in the clear that helped to value the information
encoded, and a lot of brute strength repetitive attempts.

It's not that different from today, when we read about the "evil hackers"
and then it turns out not technical skill but social skill or blunder has
gotten them secret information.

If they knew something might be important, from where it was coming from,
they would allocate resources to figure it out. And they were lucky that
the users of enigma got sloppy, just like people today use easy to
remember passwords.

Michael

[Michael Black]

On Fri, 23 Oct 2015, Osmium wrote:

She isn't yet 90 either. I was thinking of suggesting to my mother, who
turned 92 in August, that she send a birthday card to the Queen next year
on her 90th. Kind of a reverse, the queen will send cards for certain
epic dates in people's lives, though the standards are high enough that it
eliminates most people.

Prince Philip is 94. I was thinking he might be younger, that happens
sometimes, but apparently not.

I hear the Queen won't take in any more corgis now, she's worried about
tripping over them.

Michael

[Osmium]

I guess we disagree. However, I think we are discussing gradations of
infinity. Since my Enigma protocol is mostly imaginary, but a necessary
part of a resolution, we can't resolve it.

I assume that, because of speed constraints, only keys are exchanged by
Diffie-Hellman techniques and real messages, such as bank transfers, use
something more mundane like DES. I Would expect new keys to be exchanged
infrequently, say monthly or yearly. The DH password is for life, the life
of a person or an organization.

A perfect technique would allow any message as a possible decrypt. If I
saw *an* Enigma decrypt I would most likely think it was an actual message
decrypt tether than a chance result. OTOH if I saw such from a
Diffie-Hellamn message with a sizeable key it seems, somehow, a more
credible claim. But either of those *could be* freak instances, neither
system is perfect. After all, it doesn't take a very long message to
transfer a hundred billion Euros from one account to another.

[Jon Elson]

Osmium wrote:


> I have probably read as much as anyone on Enigma. And I *still* don't
> know just how breakable it is. There are a lot of people spouting off who
> shouldn't be, and I have difficulty separating what those people said from
> the trustworthy people. In my mind, I guess, I think the Enigma is not
> very
> breakable at all. To me, the most interesting question is: "Can the
> Enigma
> be broken without cribs"?

Apparently, it can, but that slows down the process quite a bit. You can
have programs that look for typical character strings to guess which
settings might be producing a clear text result.

> My tentative answer is "no", in other words a
> workable protocol for usage can be established and the Enigma is virtually
> unbreakable. Today.
>

There are programs you can download on the web that do essentially what the
Bombes did, and scans the results for likely results.

So, with a small farm of desktop computers, I think you can crack enigma
messages in fairly short order. See :

http://www.enigma.hoerenberg.com/index.php?cat=Breaking%20the%20M4
http://www.cnet.com/news/distributed-computing-cracks-enigma-code/

I think a lot more interesting problem would be cracking the SZ26 cipher,
which was a lot more sophisticated. The Bletchely Park group had to invent
a digital device to crack that (Colossus), and needed cribs to make much
progress.

Jon

[Jon Elson]

Michael Black wrote:


>>
> I've read some, and the impression I got was that having the machine, from
> the Poles, didn't in itself solve the problem. They really did rely on
> blunder, the sequence not changed the way it should have been, and
> information sent in the clear that helped to value the information
> encoded, and a lot of brute strength repetitive attempts.
>

Without knowing the wiring of the rotors, you are REALLY in the dark, and it
would take a HUGE number of messages to get any entry into the cipher.

The Germans DID change out the rotors on all Enigmas in, I think, 1940, and
Bletchley Park took 21 months to figure it out. Then, the Germans went to a
4-rotor enigma in 1942.

There were some VERY revealing blunders, like a guy who sent a message where
the cleartext was all letter "L". Due to the way Enigma works, the
ciphertext would have ZERO letter L's in it, a dead giveaway to
cryptanalysts working on it.

Also, if two different messages were sent with the same key, that could
reveal some info about the key.

Jon

[danny burstein]

In <TpWdnfeJpulPCbfL...@giganews.com> Jon Elson <el...@pico-systems.com> writes:

>Michael Black wrote:

>Also, if two different messages were sent with the same key, that could
>reveal some info about the key.

and, natch, if the memos would always end
with the phrase "Heil Hitler!" that would
give you (the decrypter) a head start..

--
_____________________________________________________
Knowledge may be power, but communications is the key
dan...@panix.com
[to foil spammers, my address has been double rot-13 encoded]

[Osmium]

Thanks, I found the second one especially helpful. As you might know I am
hung up on the cribs aspect of this, so I treed to harvest cribs from the
message they extracted. It was a goldmine (for submarine use): forced,
submerge, attack, depth, charges, knots, following, visibility. This
afternoon it seems more crackable than it was this morning. Perhaps it
actually supports my belief that they *had* to use cribs; but something I
wasn't sufficiently aware of, crib words are inevitable.

[Osmium]

"danny burstein" wrote:


>>Michael Black wrote:
>
>>Also, if two different messages were sent with the same key, that could
>>reveal some info about the key.
>
> and, natch, if the memos would always end
> with the phrase "Heil Hitler!" that would
> give you (the decrypter) a head start..

There was some bozo in Africa who kept ending "nothing to report".

I think there is a message here: do not give sharp tools to someone with no
training.

[Osmium]

Sending, not ending.

[Gene Wirchenko]

On Fri, 23 Oct 2015 13:36:43 -0400, Michael Black <et...@ncf.ca>
wrote:

[snip]

>I've read some, and the impression I got was that having the machine, from
>the Poles, didn't in itself solve the problem. They really did rely on
>blunder, the sequence not changed the way it should have been, and
>information sent in the clear that helped to value the information
>encoded, and a lot of brute strength repetitive attempts.

As I understand it, the Nazis started each message about the same
way, and that gave an in. (Whom it was addressed to, etc.)

[snip]

Sincerely,

Gene Wirchenko

[Bob Eager]

They started with the rotor settings (twice) and that weakened it
considerably. Then, as you say, certain users always used the same format
for messages (e.g. weather reports).

It was also known for the British to send the RAF out to depth charge
somewhere (Bay of Biscay comes to mind) to trigger a known-form message
if other traffic was absent.


--
Using UNIX since v6 (1975)...

Use the BIG mirror service in the UK:
http://www.mirrorservice.org

[JimP]

On Fri, 23 Oct 2015 14:14:12 -0700, Gene Wirchenko <ge...@telus.net>
wrote:

That matches what I've seen in several documentaries on WW2 and
Enigma.
--
JimP.

[Dave Garland]

Plus, occasionally a message needed to be resent. Probably detected
because it had the same number of characters as a previous message.

I gather that sports scores were another popular bit of content.

[78lp]

"Morten Reistad" <fi...@last.name.invalid> wrote in message
news:bi8pfc-...@sambook.reistad.name...

Liz has no subject nations. Her dad didn’t have any either.

> none of which should eavesdrop on any other.

They do it all the time, as Snowdon exposed.

[78lp]

"Greymaus" <ma...@mail.com> wrote in message

news:slrnn2k8c8...@dmaus.org...

> On 2015-10-23, Morten Reistad <fi...@last.name.invalid> wrote:
>> In article <d8tnd3...@mid.individual.net>, 78lp <78...@nospam.com>
>> wrote:
>>>
>>>
>>>"Greymaus" <ma...@mail.com> wrote in message
>>>news:slrnn2hltd...@dmaus.org...
>>>> On 2015-10-21, Jon Elson <el...@pico-systems.com> wrote:
>>>>> David Griffith wrote:
>>>>>
>>>> The Question: Why was the whole Enigma project kept secret so long
>>>
>>
>> One tidbit here; the Queen of the UK and a score of other
>> nations keeps her own crypto machines jealously guarded and
>> the UK is not involved, except as consultants for the
>> secrecy.
>>
>> The royals operate the cipher machines themselves, and no
>> servants are allowed in the room while this happens. This
>> is very unusual for royals; they usually have servants
>> doing everything for them.
>>
>> The rationale is that she needs secure channels to all
>> her subject nations, none of which should eavesdrop on any
>> other.
>
>
> I find all that hard to believe, an 80++year woman, and her
> 90++ old husband?.

Yeah, me too. She may well have done at one time, but I bet
she doesn’t anymore.

> She really has no subjects any more, the
> `Commonwealth' is a group of (mosty white) countries that have gone their
> seperate ways.

Yep, and even her dad didn’t have any either.

> There is supposadly an onionlke organization of countries
> the the US share data, and the inner core is these countries
> (Canada, Australia, New Zealand, the UK).

Yep, the 5 eyes group.
https://en.wikipedia.org/wiki/Five_Eyes

The only reason NZ is included is because it would otherwise be the
4 eyes group and it was felt that that name would be a tad down market.

[Stan Barr]

On Fri, 23 Oct 2015 13:40:24 -0400, Michael Black <et...@ncf.ca> wrote:
>>
> She isn't yet 90 either. I was thinking of suggesting to my mother, who
> turned 92 in August, that she send a birthday card to the Queen next year
> on her 90th. Kind of a reverse, the queen will send cards for certain
> epic dates in people's lives, though the standards are high enough that it
> eliminates most people.
>

The Palace sends cards for the 100th birthday and each year thereafter.
My mother is expecting her first next March...

--
Stan Barr pla...@bluesomatic.org

[Greymaus]

There was a thing that certain messages would start with "Heil Hitler",
which was a good start.

[Greymaus]

On 2015-10-23, Michael Black <et...@ncf.ca> wrote:
> This message is in MIME format. The first part should be readable text,
> while the remaining parts are likely unreadable without MIME-aware tools.
>
> --8323328-1748672732-1445621803=:21502
> Content-Type: TEXT/PLAIN; charset=Windows-1252; format=flowed
> Content-Transfer-Encoding: QUOTED-PRINTABLE

>
> On Fri, 23 Oct 2015, Osmium wrote:
>
>>
>> "78lp" wrote:
>>

>>> "Greymaus" <ma...@mail.com> wrote in message=20
> information sent in the clear that helped to value the information=20

> encoded, and a lot of brute strength repetitive attempts.
>

> It's not that different from today, when we read about the "evil hackers"=
>=20
> and then it turns out not technical skill but social skill or blunder has=
>=20
> gotten them secret information.
>
> If they knew something might be important, from where it was coming from,=
>=20
> they would allocate resources to figure it out. And they were lucky that=
>=20
> the users of enigma got sloppy, just like people today use easy to=20
> remember passwords.
>
> Michael
>
> --8323328-1748672732-1445621803=:21502--

Who seems to know something aabout all that, Mr. Schnier(sp?) makes the
point that secure passwords are a balaance between ease-of-remembering
and security.

In reference to the Prince Philip hack years ago, mentioned elsewhere,
I think it turned out laater that the `hacker' worked in the next office to
the email server that the account was on.

I think that a lot of hacking incidences are systems that are insufficently
tested before being opened to public access. In one instance here, system was
opened to public access, crashed, the fat heads in charge blamed `hackers',
then actual professionals were brought in to run it.

[Greymaus]

On 2015-10-23, Michael Black <et...@ncf.ca> wrote:

> On Fri, 23 Oct 2015, Osmium wrote:
>
>> "Greymaus" wrote:
>>
>>> On 2015-10-23, Morten Reistad <fi...@last.name.invalid> wrote:
>>>> In article <d8tnd3...@mid.individual.net>, 78lp <78...@nospam.com>
>>>> wrote:
>>>>>
>>>>>
>>>>> "Greymaus" <ma...@mail.com> wrote in message
>>>>> news:slrnn2hltd...@dmaus.org...
>>

> She isn't yet 90 either. I was thinking of suggesting to my mother, who
> turned 92 in August, that she send a birthday card to the Queen next year

Don't forget the cheque: I once sent a cheque to a famous man, in the course of
business, unfortunatly (It was many years ago), I forgot to keep the returned
cashed. Now when I tell people of it, they will not believe it.

I believe that for many years, Dr. Knuth would pay for any reports of errors in
TeX, cost him nothing because ppeople do not cash his cheques, but keep them
on display.

> on her 90th. Kind of a reverse, the queen will send cards for certain
> epic dates in people's lives, though the standards are high enough that it
> eliminates most people.
>
> Prince Philip is 94. I was thinking he might be younger, that happens
> sometimes, but apparently not.
>
> I hear the Queen won't take in any more corgis now, she's worried about
> tripping over them.
>
> Michael
>

(The Queen used to send a cheque to 100th birthday people)

[Michael Black]

And a computer from today would certainly help. Do the analytics on each
message, save someone from having to do it by hand. Since the old
messages would be on the hard drive, that makes it so much easier to check
previous messages or compare.

It's not unlike any intelligence work. Look at data, make a hypothesis,
then set out to prove it. Sometimes it matches, other times you're proved
wrong.

MIchael

[David Wade]

On 23/10/2015 21:25, danny burstein wrote:
> In <TpWdnfeJpulPCbfL...@giganews.com> Jon Elson <el...@pico-systems.com> writes:
>
>> Michael Black wrote:
>
>> Also, if two different messages were sent with the same key, that could
>> reveal some info about the key.
>
> and, natch, if the memos would always end
> with the phrase "Heil Hitler!" that would
> give you (the decrypter) a head start..
>

I seem to remember that one station in the dessert always sent the same
message, something like "sunny, nothing has happened". Then one day the
message changed and the Code Breakers spent a lot of time decoding it
only to find it read..

"A Camel Walked Past, Still Sunny"

but generally German blind ahdherence to procedures made the code easier
to crack..

Dave

[Morten Reistad]

In article <d8vphqF...@mid.individual.net>,

There were also incidents of large propaganda rants which were
sent in both clear and encrypted.

These were identifiable because of the length, and gave a long
clear text to the codebreakers.

-- mrr

[Charles Richmond]

"Greymaus" <ma...@mail.com> wrote in message

news:slrnn2ms88...@dmaus.org...
>
> [snip...] [snip...]
> [snip...]

>
> Don't forget the cheque: I once sent a cheque to a famous man, in the
> course of
> business, unfortunatly (It was many years ago), I forgot to keep the
> returned
> cashed. Now when I tell people of it, they will not believe it.
>
> I believe that for many years, Dr. Knuth would pay for any reports of
> errors in
> TeX, cost him nothing because ppeople do not cash his cheques, but keep
> them
> on display.
>

https://en.wikipedia.org/wiki/Knuth_reward_check

--

numerist at aquaporin4 dot com

[Walter Bushell]

In article <n0e537$37l$1...@reader1.panix.com>,

danny burstein <dan...@panix.com> wrote:

> In <TpWdnfeJpulPCbfL...@giganews.com> Jon Elson
> <el...@pico-systems.com> writes:
>
> >Michael Black wrote:
>
> >Also, if two different messages were sent with the same key, that could
> >reveal some info about the key.
>
> and, natch, if the memos would always end
> with the phrase "Heil Hitler!" that would
> give you (the decrypter) a head start..

Wouldn't that be a tail start?

--
Never attribute to stupidity that which can be explained by greed. Me.

[Jon Elson]

Walter Bushell wrote:

> In article <n0e537$37l$1...@reader1.panix.com>,
> danny burstein <dan...@panix.com> wrote:
>
>> In <TpWdnfeJpulPCbfL...@giganews.com> Jon Elson
>> <el...@pico-systems.com> writes:
>>
>> >Michael Black wrote:
>>
>> >Also, if two different messages were sent with the same key, that could
>> >reveal some info about the key.
>>
>> and, natch, if the memos would always end
>> with the phrase "Heil Hitler!" that would
>> give you (the decrypter) a head start..
>
> Wouldn't that be a tail start?
>

Yup, and the bombes were actually built so they could work back from the end
of the messages, not just forwards from the beginning, as they knew a number
of the cribs would occur at the closing of the messages!

Jon