Can you find the hidden six-letter word?
Below are, in chronological order, six extracts from written works, both fiction and non-fiction, with a bearing on cryptography or intelligence. Five of these are taken from the beginning of the work in question, and one is from the beginning of a chapter.
You will need to decode all six extracts and identify the works. Once you have all the answers, you need to find the hidden six-letter word.