What is plaintext?

Plaintext can refer to anything which humans can understand and/or relate to. This may be as simple as English sentences or a script, or Java code. If you can make sense of what is written, then it is in plaintext.

Example: We will encrypt a sentence using Caesar Cipher. The key is 7, that means a becomes h.

Plaintext : This is a plaintext.

Ciphertext : Aopz pz h wshpualea.