The commit ab5ae32bae is the last commit
for the second edition, so all changes since then are dropped except for
several commits for the third edition authored by Andreas Antonopoulos.
No attempt is made to remove CC-BY-SA or other licensed content present
in the already-published first or second editions.
This revert may itself be reverted for versions of the book published
under CC-BY-SA.
The 'pybitcointools' library is deprecated. Vitalik mentions using the
fork from 'primal100'. This updates the code sample which is currently
broken, to use the Python package for that fork.
Runs all good now.
When testing with a `private_key = '0000000000000000000000000000000000000000000000000000000000000001'` instead of `private_key = bitcoin.random_key()`,
the generated Private Key (WIF-Compressed) is wrong `5HpHagT65TZzG1PH3CSu63k8DbpvD8s5ip4nEB3kEsrefhvB5QZ`, it should be `KwDiBf89QgGbjEhKnhXJuH7LrciVrZi3qYjgd9M7rFU73sVHnoWn`. As it turns out, the proper way to get the correct compressed WIF is to pass `'wif_compressed'` and not `'wif'` to the `bitcoin.encode_privkey` function, as pointed out in the Main.py from the bitcoin python package.
```
def encode_privkey(priv, formt, vbyte=0):
if not isinstance(priv, int_types):
return encode_privkey(decode_privkey(priv), formt, vbyte)
if formt == 'decimal': return priv
elif formt == 'bin': return encode(priv, 256, 32)
elif formt == 'bin_compressed': return encode(priv, 256, 32)+b'\x01'
elif formt == 'hex': return encode(priv, 16, 64)
elif formt == 'hex_compressed': return encode(priv, 16, 64)+'01'
elif formt == 'wif':
return bin_to_b58check(encode(priv, 256, 32), 128+int(vbyte))
elif formt == 'wif_compressed':
return bin_to_b58check(encode(priv, 256, 32)+b'\x01', 128+int(vbyte))
else: raise Exception("Invalid format!")
```
The fix can be done in a couple ways:
`bitcoin.encode_privkey(bitcoin.decode_privkey(compressed_private_key, 'hex'), 'wif')` -> 5HpHagT65TZzG1PH3CSu63k8DbpvD8s5ip4nEB3kEsrefhvB5QZ (WRONG)
`bitcoin.encode_privkey(bitcoin.decode_privkey(compressed_private_key, 'hex'), 'wif_compressed')` -> KwDiBf89QgGbjEhKnhXJuH7LrciVrZi3qYjgd9M7rFU9FMLM39zT (WRONG)
`bitcoin.encode_privkey(bitcoin.decode_privkey(compressed_private_key, 'hex_compressed'), 'wif_compressed')` -> KwDiBf89QgGbjEhKnhXJuH7LrciVrZi3qYjgd9M7rFU73sVHnoWn (CORRECT)
`bitcoin.encode_privkey(bitcoin.decode_privkey(private_key, 'hex'), 'wif_compressed')` -> KwDiBf89QgGbjEhKnhXJuH7LrciVrZi3qYjgd9M7rFU73sVHnoWn (CORRECT)
If line#24 use 'wif_compressed', it will produce a wrong Key (WIF-Compressed) started with 2.
So there should be 'wif', unless :
wif_compressed_private_key = bitcoin.encode_privkey(
bitcoin.decode_privkey(private_key, 'hex'), 'wif_compressed')
This is also right.
However, use the 'compressed_private_key' and 'wif_compressed' is wrong.
The bug is that `x % 255` is not quite the same thing as `x % 256`;
but `x & 255` is.
The stylistic issue is that `numeric_limits<uint8_t>::max()` is a
very verbose way of spelling `255`.
The code is very possible to miss a leading '0'.
E.g:
Private Key (hex) is: 57c003d31cca32f79a22e70334fff37875617e89c04d2746b5efc22067ccb8fd
Before: Compressed Public Key (hex) is: 03 8f0de2360796ae0fe17f1a2b0be30af6fb45eccc4a1c7afb5ebea21d041b6e0
After: Compressed Public Key (hex) is: 03 08f0de2360796ae0fe17f1a2b0be30af6fb45eccc4a1c7afb5ebea21d041b6e0
The bug is in the pybitcointools, but it is not updated, we can only repair it ourselves.
As input and hash are inbuilt functions, so I'd suggest using other names for variables.
here is output from python interpreter.
>>> hash
<built-in function hash>
>>> input
<built-in function input>
`from __future__ import print_function` to bring the print function from Python 3 into Python 2.6 and 2.7.
Properly deals with comma separated values in print() function.
