- Goal
  - You need to generate {num} test samples according to given instructions, aiming to comprehensively evaluating the correctness of encryption programme.
  - For each task sample, you need to assign
    1. `plaintext: str` which is plaintext that **only** allows uppercase or lowercase English letters (A-Z, a-z) and blank space.

- Instruction
1. The encryption programme implements {algorithm}.

2. `plaintext` **must not** (1) exceed the length of 32. (2) contain very simple and common words or phrases (e.g. hello world). (3) any information that might leak the encryption programme.

3. Make sure the generated `plaintext` cover diverse situations: long input, short input, input with blank space, input without blank space, input with mixed uppercase and lowercase letters, input with random letters, input with normal collocation.