# basex
Encoding/decoding of any given alphabet with any base using bitcoin style leading zero compression
This is a port of js base-x package from [`cryptocoinjs/base-x`](https://github.com/cryptocoinjs/base-x).
**WARNING:** This module is **NOT RFC3548** compliant, it cannot be used for base16 (hex), base32, or base64 encoding in a standards compliant manner.
## Example
Base58
``` python
from basex import basex
BASE58 = '123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz'
bs58 = basex(BASE58)
decoded = bs58.decode('5Kd3NBUAdUnhyzenEwVLy9pBKxSwXvE9FMPyR4UKZvpe6E3AgLr')
print(decoded)
# => bytearray(b'\x80\xed\xdb\xdc\x11h\xf1\xda\xea\xdb\xd3\xe4L\x1e?\x8fZ(L )\xf7\x8a\xd2j\xf9\x85\x83\xa4\x99\xde[\x19\x13\xa4\xf8c')
print(bs58.encode(decoded))
# => 5Kd3NBUAdUnhyzenEwVLy9pBKxSwXvE9FMPyR4UKZvpe6E3AgLr
```
### Alphabets
See below for a list of commonly recognized alphabets, and their respective base.
Base | Alphabet
------------- | -------------
2 | `01`
8 | `01234567`
11 | `0123456789a`
16 | `0123456789abcdef`
32 | `0123456789ABCDEFGHJKMNPQRSTVWXYZ`
32 | `ybndrfg8ejkmcpqxot1uwisza345h769` (z-base-32)
36 | `0123456789abcdefghijklmnopqrstuvwxyz`
58 | `123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz`
62 | `0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ`
64 | `ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/`
67 | `ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_.!~`
## How it works
It encodes octet arrays by doing long divisions on all significant digits in the
array, creating a representation of that number in the new base. Then for every
leading zero in the input (not significant as a number) it will encode as a
single leader character. This is the first in the alphabet and will decode as 8
bits. The other characters depend upon the base. For example, a base58 alphabet
packs roughly 5.858 bits per character.
This means the encoded string 000f (using a base16, 0-f alphabet) will actually decode
to 4 bytes unlike a canonical hex encoding which uniformly packs 4 bits into each
character.
While unusual, this does mean that no padding is required and it works for bases
like 43.
## LICENSE [MIT](LICENSE)
A direct derivation of the base58 implementation from [`bitcoin/bitcoin`](https://github.com/bitcoin/bitcoin/blob/f1e2f2a85962c1664e4e55471061af0eaa798d40/src/base58.cpp), generalized for variable length alphabets.
