New circulating commemorative:
"75th Anniversary of Breaking Enigma Codes"
Enigma machines:

In the history of cryptography,
Enigma was a cipher machine used to encrypt and decrypt secret messages. More precisely, Enigma was a family of related electro-mechanical rotor machines comprising a variety of different models.
The Enigma was used commercially from the early 1920s on, and was also adopted by the military and governmental services of a number of nations, most famously by
Nazi Germany before and during World War II.
The German military model, the
Wehrmacht Enigma, is the version most commonly discussed. The machine has gained notoriety because
Allied cryptologists were able to decrypt a large number of messages that had been enciphered on the machine.
The works on the Enigma were carried out by three young mathematicians engaged by the
Polish counter-intelligence, graduates from
Poznan University:
Marian Rejewski,
Henryk Zygalski and
Jerzy Rózycki, who specialised in the encryption theory.
In the 1930s, they developed the mathematical basis of the Enigma and the apparatus for the deduction of the current settings of the machine's rotors and plugs.
In mid-1939 reconstruction and decryption methods were delivered to
Britain and France. The intelligence gained through this source was a significant aid to the Allied war effort.
LINK:
National Bank of PolandLINK:
Polish State MintLINK:
Enigma in WikipediaLINK:
Enigma models and imagesLINK:
Modern Enigma machinesSPECIFICATIONS
Composition: Nordic gold, CuAl5Zn5Sn1
Weight: 8.15 g
Diameter: 27.00 mm
Mintage: 900,000