JN-25 served as which type of code?

JN-25 served as which type of code?

• A. Army cipher
• B. Navy general-purpose code
• C. Air Force code
• D. Allied code

Answer: (B)

JN-25 is the Imperial Japanese Navy’s general-purpose code, used to send a wide range of naval messages. It’s classified as a code because it relies on codebooks that substitute coded phrases or words for their plaintext meanings, rather than applying a letter-by-letter substitution with a key (which would be a cipher). It was specifically a Navy system, not an Army or Air Force one, and it wasn’t an Allied code. Its broad, versatile nature made it the go-to method for routine naval communications, and its eventual cryptanalysis by Allied teams had a major impact on the Pacific war.

JN-25 is the Imperial Japanese Navy’s general-purpose code, used to send a wide range of naval messages. It’s classified as a code because it relies on codebooks that substitute coded phrases or words for their plaintext meanings, rather than applying a letter-by-letter substitution with a key (which would be a cipher). It was specifically a Navy system, not an Army or Air Force one, and it wasn’t an Allied code. Its broad, versatile nature made it the go-to method for routine naval communications, and its eventual cryptanalysis by Allied teams had a major impact on the Pacific war.