secret writing

• 一种将信息编码或隐藏起来的方法，使只有预期接收者才能读取，通常与密码学或隐写术相关。

A method of encoding or concealing information so that only intended recipients can read it, often associated with cryptography or steganography.

1. CryptographyB2formal

   The practice of writing messages in a code or cipher so that only the intended recipient can read them.

   密码学

   • Secret writing was used by spies during the war.
   • The ancient Egyptians used hieroglyphs as a form of secret writing.
   • Modern secret writing relies on complex algorithms.

2. Invisible inkB1informal

   A substance used for writing that is invisible until it is treated with a chemical or heat.

   隐形墨水

   • The children used lemon juice for secret writing.
   • The spy wrote a message in secret writing using invisible ink.
   • Secret writing can be revealed by holding the paper over a flame.