Lesson plan
Trench code
Trench codes (a form of cryptography) were codes used for secrecy by field armies in World War I. Messages by field telephone, radio and carrier pigeons could be intercepted, hence the need for tactical World War I cryptography. Originally, the most commonly used codes were simple substitution codes, but due to the relative vulnerability of the classical cipher, trench codes came into existence. (Important messages generally used alternative encryption techniques for greater security.) The use of these codes required the distribution of codebooks to military personnel, which proved to be a security liability since these books could be stolen by enemy forces. By the middle of World War I the conflict had settled down into a static battle of attrition, with the two sides sitting in huge lines of fixed earthwork fortifications. With armies generally immobile, distributing codebooks and protecting them was easier than it would have been for armies on the move. However, armies were still in danger of trench-raiding parties who would sneak into enemy lines and try to snatch codebooks. When this happened, an alarm could be raised and a code quickly changed. Trench codes were changed on a regular basis in an attempt to prevent code breakers from deciphering messages.
Article summary
Trench codes (a form of cryptography) were codes used for secrecy by field armies in World War I. Messages by field telephone, radio and carrier pigeons could be intercepted, hence the need for tactical World War I cryptography. Originally, the most commonly used codes were simple substitution codes, but due to the relative vulnerability of the classical cipher, trench codes came into existence. (Important messages generally used alternative encryption techniques for greater security.) The use of these codes required the distribution of codebooks to military personnel, which proved to be a security liability since these books could be stolen by enemy forces. By the middle of World War I the conflict had settled down into a static battle of attrition, with the two sides sitting in huge lines of fixed earthwork fortifications. With armies generally immobile, distributing codebooks and protecting them was easier than it would have been for armies on the move. However, armies were still in danger of trench-raiding parties who would sneak into enemy lines and try to snatch codebooks. When this happened, an alarm could be raised and a code quickly changed. Trench codes were changed on a regular basis in an attempt to prevent code breakers from deciphering messages.
Key claims
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Discussion questions
- Summarise the article in your own words. Which single claim would you verify first, and why?
- Which claim in this article is most likely to be revised as the sources update? How would you check its current status?
- If two sources disagreed about one of these facts, what would you need in order to trust one over the other?
Bibliography
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Key claims and bibliography are generated from the same tracked claims and sources as the article page.