Generating a Bitcoin Private Key and Address

Ken Shirriff’s blog post here has an excellent introduction to Bitcoin. One of his code snippets shows a sample python code to generate a private key in WIF format and an address. I tweaked it just a bit to replace usage of python’s random module with os.urandom and stripped it down to just what’s needed to show the exponent, private key and address. Here’s the effort in a gist:

	import ecdsa
	import ecdsa.der
	import ecdsa.util
	import hashlib
	import os
	import re
	import struct
	b58 = '123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz'
	def base58encode(n):
	result = ''
	while n > 0:
	result = b58[n%58] + result
	n /= 58
	return result
	def base256decode(s):
	result = 0
	for c in s:
	result = result * 256 + ord(c)
	return result
	def countLeadingChars(s, ch):
	count = 0
	for c in s:
	if c == ch:
	count += 1
	else:
	break
	return count
	# https://en.bitcoin.it/wiki/Base58Check_encoding
	def base58CheckEncode(version, payload):
	s = chr(version) + payload
	checksum = hashlib.sha256(hashlib.sha256(s).digest()).digest()[0:4]
	result = s + checksum
	leadingZeros = countLeadingChars(result, '\0')
	return '1' * leadingZeros + base58encode(base256decode(result))
	def privateKeyToWif(key_hex):
	return base58CheckEncode(0x80, key_hex.decode('hex'))
	def privateKeyToPublicKey(s):
	sk = ecdsa.SigningKey.from_string(s.decode('hex'), curve=ecdsa.SECP256k1)
	vk = sk.verifying_key
	return ('\04' + sk.verifying_key.to_string()).encode('hex')
	def pubKeyToAddr(s):
	ripemd160 = hashlib.new('ripemd160')
	ripemd160.update(hashlib.sha256(s.decode('hex')).digest())
	return base58CheckEncode(0, ripemd160.digest())
	def keyToAddr(s):
	return pubKeyToAddr(privateKeyToPublicKey(s))
	# Generate a random private key
	private_key = os.urandom(32).encode('hex')
	# You can verify the values on http://brainwallet.org/
	print "Secret Exponent (Uncompressed) : %s " % private_key
	print "Private Key : %s " % privateKeyToWif(private_key)
	print "Address : %s " % keyToAddr(private_key)

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keyUtils.py

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