README.md in paperback-0.0.3 vs README.md in paperback-0.0.4
- old
+ new
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# Paperback
[](https://rubygems.org/gems/paperback)
-[](https://travis-ci.org/ab/paperback)
-[](https://codeclimate.com/github/ab/paperback)
[](http://www.rubydoc.info/github/ab/paperback/master)
*Paperback* is a library that facilitates the creation of paper offline backups
of small amounts of important data, such as encryption keys.
It is designed to be used for long-term paper storage. Arbitrary data to be
-backed up is encoded using QR codes and
-[sixword](https://github.com/ab/sixword) English text.
+backed up is encoded using QR codes,
+[sixword](https://github.com/ab/sixword) English text, and Base64.
+Nothing else approaches the durability and inexpensiveness of paper. This
+library is designed to facilitate the restoration process, which would be
+tedious and error-prone when using human typists or even OCR.
+
+The QR code is easily machine readible, the sixword text is easiest to
+transcribe for humans, and the Base64 serves as a fallback for broadest
+compatibility.
+
By default, the backup data is GPG-encrypted with a symmetric passphrase to
avoid exposing data to the printer (or scanner, assuming you cover the
passphrase when scanning).
+The printed document does contain the SHA256 digest of the original content for
+error correction, which is not a problem for random data like keys. But if you
+are backing up low-entropy secrets and want to preserve the printer-blindness
+property, pad the content with a random salt or encrypt it before using
+paperback.
+
## Usage
-Typical usage will be through the `paperback` executable.
+Typical usage will be through the `paperback` executable. Use the `--help`
+option for a usage menu.
```sh
# Back up the content in data.key
paperback data.key out.pdf
```
+
+### Sample output
+
+See [sample directory](./sample)
+
### More complex patterns
See the [YARD documentation](http://www.rubydoc.info/github/ab/paperback/master).