Base32 encoding and decoding
Base 32 is between hexadecimal notation and Base 64 encoding. It's intended to be a human-friendly -- you don't have to worry about punctuation, capitalization, or letters/numbers that are easy to confuse, making it easier to transmit in handwriting or over the phone.
One of the primary purposes is to have aesthetically pleasing SHA1 hashes. Compare:
Try giving out the Base 64 hash over the phone! "lowercase 'x', capital 'E', underscore, lowercase 'p', ..." Base 32 will work the same with upper- or lowercase, you can mistake a number for a similar-looking letter, and it will still decode to the same data.
In your shell, install with npm:
npm install base32
In your code:
var base32 = require'base32'// simple apivar encoded = base32encode'some data to encode'var decoded = base32decodeencoded// streaming apithisencoder =thisemitthisencoderchunkthisemitthisfinish // flush any remaining bits// easy sha1 hashvar hash = base32sha1some_data_to_hash // DONE.
On the command-line (to install system-wide, use
npm install -g base32):
base32 -h#> Usage: base32 [input_file] [-o output_file] [-d|--decode] [-s|--sha]echo "Hello World" | base32#> 91jprv3f41bpywkccg50echo 'axqqeb10d5u20wk5c5p6ry90exqq4uvk44' | base32 -d#> Wow, it really works!base32 -s test/*#> ky2t1raumjn9cghne773petngx3zz3q7 test/base32-test.coffee#> 6b4bkjaveddmg5jh7hnyw132yht20g6e test/compare.coffee
There are about (128 choose 32) different specifications of something called "Base 32" - see Wikipedia for some of them.
This is just one that should be simple, less error-prone, and streamable (for Node).
The encoding alphabet consists of the numerals 0-9 and the letters a-z, excluding a few letters that might look like numbers, which we simply interpret as follows:
- I -> 1
- L -> 1
- O -> 0
- S -> 5
When decoding, capital letters are converted to lowercase and the "ambiguous" letters mentioned above converted to their numeric counterparts.
Each character corresponds to 5 bits of input.
Lexicographic order of strings is preserved through Base 32 encoding.
Under MIT License.
Fork as much as you like, I'm more than amenable to pull requests. I'm trying to keep it reasonably node-ish, so bear that in mind.