Final answer:
Ciphertext is the scrambled text produced by an encryption algorithm. The Zimmerman Telegram used a Transposition Cipher, which rearranges plaintext letters in blocks based on a keyword.
Step-by-step explanation:
Text that has been scrambled by an encryption algorithm is known as ciphertext. When encrypting a message, plain text is converted into ciphertext to prevent unauthorized parties from reading the content. The Zimmerman Telegram, for example, utilized a Transposition Cipher, a method of encryption where the letters in the plaintext are rearranged according to a rule. A common technique involves dividing the plaintext into blocks and then changing the order of the letters in each block. The size of the blocks and the specific changes made to the letters' order can be determined by a keyword. This process obscures the original message, making it unreadable without the proper decryption key or method.