Converting binary to string can be useful when you need to represent a number in a recognizable, short package. For this task, Base64 is often used.
Base64 contains characters that can be confused with each other. This can lead to transcription mistakes. It is also harder to copy & paste due to special characters.
Base58 encoding prevents confusion between letters. The resulting expression is also selectable by double clicking the mouse.
Base58Check encoding
Base58Check consists of a version number, a payload, and a double sha256 hash of the payload.
First, pip install base58.
import base58
text = base58.b58encode_check(b'\0'+b'Hello world!')
>> b'19wWTEnNTWna86WmtFsTAr5'
payload = base58.b58decode_check(text)[1:]
>> b'Hello world!'
If the version byte is 0, the result always starts with a 1!
Base58Check size overhead
The Base58Check encoded string is about 37% larger for most payloads.
Generating QR Codes
import base58
import pyqrcode
text = base58.b58encode_check(b'0'+b'Hello world!')
qr = pyqrcode.create(text)
qr.png('{0}.png'.format(text), scale=8)
Encrypted payloads
Here is the code to encode ciphertext in base58:
import base58
from Crypto.Cipher import AES
from Crypto import Random
def pad(s,bs=32):
return s+(bs-len(s)%bs)*chr(bs-len(s)%bs)
def unpad(s):
return s[:-ord(s[len(s)-1:])]
def encrypt(key,payload):
key = pad(key)
payload = pad(payload)
iv = Random.new().read(AES.block_size)
cipher = AES.new(key, AES.MODE_CBC, iv)
ciphertext = base58.b58encode_check(b'\0'+iv+cipher.encrypt(payload))
return ciphertext
def decrypt(key,ciphertext):
key = pad(key)
ciphertext = base58.b58decode_check(ciphertext)
iv = ciphertext[1:AES.block_size+1]
cipher = AES.new(key, AES.MODE_CBC, iv)
payload = unpad(cipher.decrypt(ciphertext[AES.block_size+1:]))
return payload
Now let’s run it!
key = 'password'
payload = 'Hello world!'
ciphertext = encrypt(key,payload)
>> "1R7wpD8bnXx9KnhyuKT3kVb9XY6Pd3mHtDk2gwsaiP6mFbQe3btnTHTgpErwtvnAYMY6gnHb"
payload = decrypt(key,ciphertext)
>> "Hello world!"
Each time this function is run results in different cyphertext. This is because of the initalization vector used in AES.
