Spanish Embassy's cipher machine break by Czechoslovakian Secret Service and KGB
How the Czechoslovak secret service ŠtB breaks the encryption machine Gretag TC 803 at the Spanish embassy in Prague: https://www.info.cz/zpravodajstvi/cesko/akce-sumperk?odemknout=YAYLEWR8KH Detailed description of the encryption machine Gretag TC 803 : https://www.cryptomuseum.com/crypto/gretag/803/index.htm Picture of the cipher machine's daily key block "...Another break-in at the embassy took place on June 27, 1980. In this case, the State Security encountered a problem that it could not deal with. The Spanish started using the Gretag TC 803 encryption machine. ... Daily slips of paper with an encryption key were inserted into it. These were stored in a safe and bound with bookbinding cloth on three sides and in the middle. The canvas thus formed a kind of letter E with four arms. Between the canvas arms were perforated slips of metal foil that were inserted into the encryption machine. One part was designated for each day. Used and unused keys were shredded the...