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.
With a proofreader who charges by the hour, you will not discover how much proofreading will cost until the job has been finished, which gives you no chance to choose the best value. Individuals offering freelance proofreading services, who vary widely in skill level and background, may charge by the hour. Generally, their prices range from $10 to $45 per hour. Professional services that offer by-the-hour proofreading can charge up to $95 per hour. How Much Does Proofreading Cost If You Pay by the Word? It is much easier to know ahead of time how much proofreading will cost if you choose a proofreader that charges by the word or by the page. Among professional companies, charges range from two cents to seven cents per word for a 1,000-word document, depending on the factors discussed above.