thelper functions for bip32 derivations - electrum - Electrum Bitcoin wallet
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---
DIR commit 9fccf9c2871a423e7b46d9a5d021a1f165707504
DIR parent 5288f6a933172a5b3c2fe58f60eccb5de2a9fc6f
HTML Author: ThomasV <thomasv@gitorious>
Date: Tue, 1 Apr 2014 19:10:13 +0200
helper functions for bip32 derivations
Diffstat:
M lib/bitcoin.py | 24 +++++++++++++-----------
1 file changed, 13 insertions(+), 11 deletions(-)
---
DIR diff --git a/lib/bitcoin.py b/lib/bitcoin.py
t@@ -540,18 +540,17 @@ def get_pubkeys_from_secret(secret):
# However, if n is positive, the resulting private key's corresponding
# public key can be determined without the master private key.
def CKD_priv(k, c, n):
+ is_prime = n & BIP32_PRIME
+ return _CKD_priv(k, c, rev_hex(int_to_hex(n,4)).decode('hex'), is_prime)
+
+def _CKD_priv(k, c, s, is_prime):
import hmac
from ecdsa.util import string_to_number, number_to_string
order = generator_secp256k1.order()
keypair = EC_KEY(k)
- K = GetPubKey(keypair.pubkey,True)
-
- if n & BIP32_PRIME: # We want to make a "secret" address that can't be determined from K
- data = chr(0) + k + rev_hex(int_to_hex(n,4)).decode('hex')
- I = hmac.new(c, data, hashlib.sha512).digest()
- else: # We want a "non-secret" address that can be determined from K
- I = hmac.new(c, K + rev_hex(int_to_hex(n,4)).decode('hex'), hashlib.sha512).digest()
-
+ cK = GetPubKey(keypair.pubkey,True)
+ data = chr(0) + k + s if is_prime else cK + s
+ I = hmac.new(c, data, hashlib.sha512).digest()
k_n = number_to_string( (string_to_number(I[0:32]) + string_to_number(k)) % order , order )
c_n = I[32:]
return k_n, c_n
t@@ -563,17 +562,20 @@ def CKD_priv(k, c, n):
# This function allows us to find the nth public key, as long as n is
# non-negative. If n is negative, we need the master private key to find it.
def CKD_pub(cK, c, n):
+ if n & BIP32_PRIME: raise
+ return _CKD_pub(cK, c, rev_hex(int_to_hex(n,4)).decode('hex'))
+
+# helper function, callable with arbitrary string
+def _CKD_pub(cK, c, s):
import hmac
from ecdsa.util import string_to_number, number_to_string
order = generator_secp256k1.order()
- if n & BIP32_PRIME: raise
- I = hmac.new(c, cK + rev_hex(int_to_hex(n,4)).decode('hex'), hashlib.sha512).digest()
+ I = hmac.new(c, cK + s, hashlib.sha512).digest()
curve = SECP256k1
pubkey_point = string_to_number(I[0:32])*curve.generator + ser_to_point(cK)
public_key = ecdsa.VerifyingKey.from_public_point( pubkey_point, curve = SECP256k1 )
c_n = I[32:]
cK_n = GetPubKey(public_key.pubkey,True)
-
return cK_n, c_n