With secret key cryptography, a single key is used for both encryption and decryption. As shown in Figure the sender uses the key (or some set of rules) to encrypt the plain text and sends the ciphertext to the receiver. The receiver applies the same key (or ruleset) to decrypt the message and recover the plain text.
Proofreading means examining your text carefully to find and correct typographical errors and mistakes in grammar, style, and spelling. Usually, for those who do not have time, they hire a professional proofreaders to help them do it. Before You Proofread: Set your text aside for a while (15 minutes, a day, a week) between writing and proofing. Some distance from the text will help you see mistakes more easily.
In general, effective editing and proofreading require that you reread your writing carefully, that you play the role of reader rather than writer, and that you use strategies to help you slow down and examine your writing. This handout presents strategies for both editing and proofreading.