answers.py

# tag::exercise1[]
#==== Exercise 1

# Find the uncompressed SEC format for the public key where the private key secrets are:

#* 5,000
#* 2,018^5^
#* 0xdeadbeef12345
# end::exercise1[]
# tag::answer1[]
from ecc import PrivateKey
priv = PrivateKey(5000)
print(priv.point.sec(compressed=False).hex())
#04ffe558e388852f0120e46af2d1b370f85854a8eb0841811ece0e3e03d282d57c315dc72890a4\
#f10a1481c031b03b351b0dc79901ca18a00cf009dbdb157a1d10
priv = PrivateKey(2018**5)
print(priv.point.sec(compressed=False).hex())
#04027f3da1918455e03c46f659266a1bb5204e959db7364d2f473bdf8f0a13cc9dff87647fd023\
#c13b4a4994f17691895806e1b40b57f4fd22581a4f46851f3b06
priv = PrivateKey(0xdeadbeef12345)
print(priv.point.sec(compressed=False).hex())
#04d90cd625ee87dd38656dd95cf79f65f60f7273b67d3096e68bd81e4f5342691f842efa762fd5\
#9961d0e99803c61edba8b3e3f7dc3a341836f97733aebf987121
'''
# end::answer1[]
# tag::exercise2[]
==== Exercise 2

Find the compressed SEC format for the public key where the private key secrets are:

* 5,001
* 2,019^5^
* 0xdeadbeef54321
# end::exercise2[]
# tag::answer2[]
>>> from ecc import PrivateKey
>>> priv = PrivateKey(5001)
>>> print(priv.point.sec(compressed=True).hex())
0357a4f368868a8a6d572991e484e664810ff14c05c0fa023275251151fe0e53d1
>>> priv = PrivateKey(2019**5)
>>> print(priv.point.sec(compressed=True).hex())
02933ec2d2b111b92737ec12f1c5d20f3233a0ad21cd8b36d0bca7a0cfa5cb8701
>>> priv = PrivateKey(0xdeadbeef54321)
>>> print(priv.point.sec(compressed=True).hex())
0296be5b1292f6c856b3c5654e886fc13511462059089cdf9c479623bfcbe77690

# end::answer2[]
# tag::exercise3[]
==== Exercise 3

Find the DER format for a signature whose `r` and `s` values are:

----
r = 0x37206a0610995c58074999cb9767b87af4c4978db68c06e8e6e81d282047a7c6

s = 0x8ca63759c1157ebeaec0d03cecca119fc9a75bf8e6d0fa65c841c8e2738cdaec
----
# end::exercise3[]
# tag::answer3[]
>>> from ecc import Signature
>>> r = 0x37206a0610995c58074999cb9767b87af4c4978db68c06e8e6e81d282047a7c6
>>> s = 0x8ca63759c1157ebeaec0d03cecca119fc9a75bf8e6d0fa65c841c8e2738cdaec
>>> sig = Signature(r,s)
>>> print(sig.der().hex())
3045022037206a0610995c58074999cb9767b87af4c4978db68c06e8e6e81d282047a7c6022100\
8ca63759c1157ebeaec0d03cecca119fc9a75bf8e6d0fa65c841c8e2738cdaec

# end::answer3[]
# tag::exercise4[]
==== Exercise 4

Convert the following hex values to binary and then to Base58:

* `7c076ff316692a3d7eb3c3bb0f8b1488cf72e1afcd929e29307032997a838a3d`
* `eff69ef2b1bd93a66ed5219add4fb51e11a840f404876325a1e8ffe0529a2c`
* `c7207fee197d27c618aea621406f6bf5ef6fca38681d82b2f06fddbdce6feab6`
# end::exercise4[]
# tag::answer4[]
>>> from helper import encode_base58
>>> h = '7c076ff316692a3d7eb3c3bb0f8b1488cf72e1afcd929e29307032997a838a3d'
>>> print(encode_base58(bytes.fromhex(h)))
9MA8fRQrT4u8Zj8ZRd6MAiiyaxb2Y1CMpvVkHQu5hVM6
>>> h = 'eff69ef2b1bd93a66ed5219add4fb51e11a840f404876325a1e8ffe0529a2c'
>>> print(encode_base58(bytes.fromhex(h)))
4fE3H2E6XMp4SsxtwinF7w9a34ooUrwWe4WsW1458Pd
>>> h = 'c7207fee197d27c618aea621406f6bf5ef6fca38681d82b2f06fddbdce6feab6'
>>> print(encode_base58(bytes.fromhex(h)))
EQJsjkd6JaGwxrjEhfeqPenqHwrBmPQZjJGNSCHBkcF7

# end::answer4[]
# tag::exercise5[]
==== Exercise 5

Find the addresses corresponding to the public keys whose private key secrets are:

* 5002 (use uncompressed SEC on testnet)
* 2020^5^ (use compressed SEC on testnet)
* 0x12345deadbeef (use compressed SEC on mainnet)
# end::exercise5[]
# tag::answer5[]
>>> from ecc import PrivateKey
>>> priv = PrivateKey(5002)
>>> print(priv.point.address(compressed=False, testnet=True))
mmTPbXQFxboEtNRkwfh6K51jvdtHLxGeMA
>>> priv = PrivateKey(2020**5)
>>> print(priv.point.address(compressed=True, testnet=True))
mopVkxp8UhXqRYbCYJsbeE1h1fiF64jcoH
>>> priv = PrivateKey(0x12345deadbeef)
>>> print(priv.point.address(compressed=True, testnet=False))
1F1Pn2y6pDb68E5nYJJeba4TLg2U7B6KF1

# end::answer5[]
# tag::exercise6[]
==== Exercise 6

Find the WIF for the private key whose secrets are:

* 5003 (compressed, testnet)
* 2021^5^ (uncompressed, testnet)
* 0x54321deadbeef (compressed, mainnet)
# end::exercise6[]
# tag::answer6[]
>>> from ecc import PrivateKey
>>> priv = PrivateKey(5003)
>>> print(priv.wif(compressed=True, testnet=True))
cMahea7zqjxrtgAbB7LSGbcQUr1uX1ojuat9jZodMN8rFTv2sfUK
>>> priv = PrivateKey(2021**5)
>>> print(priv.wif(compressed=False, testnet=True))
91avARGdfge8E4tZfYLoxeJ5sGBdNJQH4kvjpWAxgzczjbCwxic
>>> priv = PrivateKey(0x54321deadbeef)
>>> print(priv.wif(compressed=True, testnet=False))
KwDiBf89QgGbjEhKnhXJuH7LrciVrZi3qYjgiuQJv1h8Ytr2S53a

# end::answer6[]
# tag::exercise9[]
==== Exercise 9

Create a testnet address for yourself using a long secret that only you know. This is important as there are bots on testnet trying to steal testnet coins. Make sure you write this secret down somewhere! You will be using it later to sign transactions.
# end::exercise9[]
# tag::answer9[]
>>> from ecc import PrivateKey
>>> from helper import hash256, little_endian_to_int
>>> passphrase = b'jimmy@programmingblockchain.com my secret'
>>> secret = little_endian_to_int(hash256(passphrase))
>>> priv = PrivateKey(secret)
>>> print(priv.point.address(testnet=True))
mft9LRNtaBNtpkknB8xgm17UvPedZ4ecYL

# end::answer9[]
'''


from unittest import TestCase

import helper


'''
# tag::exercise7[]
==== Exercise 7

Write a function `little_endian_to_int` that takes Python bytes, interprets those bytes in little-endian, and returns the number.
# end::exercise7[]
'''


# tag::answer7[]
def little_endian_to_int(b):
    '''little_endian_to_int takes byte sequence as a little-endian number.
    Returns an integer'''
    return int.from_bytes(b, 'little')
# end::answer7[]


'''
# tag::exercise8[]
==== Exercise 8

Write a function `int_to_little_endian` that does the reverse of the last exercise.
# end::exercise8[]
'''


# tag::answer8[]
def int_to_little_endian(n, length):
    '''endian_to_little_endian takes an integer and returns the little-endian
    byte sequence of length'''
    return n.to_bytes(length, 'little')
# end::answer8[]


class ChapterTest(TestCase):

    def test_apply(self):
        helper.little_endian_to_int = little_endian_to_int
        helper.int_to_little_endian = int_to_little_endian