def decrypt(encrypted_privkey, passphrase):
# 1. Collect encrypted private key and passphrase from user.
# passed as parameters
data = enc.b58decode(encrypted_privkey)
flagbyte = data[2:3]
check = data[-4:]
if check != hashlib.sha256(hashlib.sha256(data[:-4]).digest()).digest()[:4]:
return False, 'checksum'
addresshash = data[3:7]
encryptedhalf1 = data[7:23]
encryptedhalf2 = data[23:39]
#3. Derive decryption key for seedb using scrypt with passpoint, addresshash, and ownersalt
key = scrypt.hash(passphrase, addresshash, 16384, 8, 8)
derivedhalf1 = key[0:32]
derivedhalf2 = key[32:64]
#4. Decrypt encryptedpart2 using AES256Decrypt to yield the last 8 bytes of seedb and the last 8 bytes of encryptedpart1.
Aes = aes.Aes(derivedhalf2)
decryptedhalf2 = Aes.dec(encryptedhalf2)
#5. Decrypt encryptedpart1 to yield the remainder of seedb.
decryptedhalf1 = Aes.dec(encryptedhalf1)
priv = decryptedhalf1 + decryptedhalf2
priv = binascii.unhexlify('%064x' % (long(binascii.hexlify(priv), 16) ^ long(binascii.hexlify(derivedhalf1), 16)))
return priv, addresshash
def encrypt(seed, passphrase): """ Encrypt the Electrum seed """ #1. Decode the seed value to the original number seed = mn_decode(seed.split()) #2. Take a hash of the decoded seed to act as a scrypt salt salt = hashlib.sha256(hashlib.sha256(seed).digest()).digest()[:4] #3. Derive a key from the passphrase using scrypt key = scrypt.hash(passphrase, salt, 16384, 8, 8) #4. Split the key into half 1 and half 2 derivedhalf1 = key[0:32] derivedhalf2 = key[32:64] #5. Do AES256Encrypt(seedhalf1 xor derivedhalf1[0...15], derivedhalf2), call the 16-byte result encryptedhalf1 # (Electrum may change the number of words in a seed so we should future proof by just using the halfs rather than hardcoded lengths) Aes = aes.Aes(derivedhalf2) encryptedhalf1 = Aes.enc(enc.sxor(seed[:int(math.floor(len(seed)/2))], derivedhalf1[:16])) #6. Do AES256Encrypt(seedhalf2 xor derivedhalf1[16...31], derivedhalf2), call the 16-byte result encryptedhalf2 encryptedhalf2 = Aes.enc(enc.sxor(seed[int(math.floor(len(seed)/2)):len(seed)], derivedhalf1[16:32])) #7. The encrypted private key is the Base58Check-encoded concatenation of the following # \x4E\xE3\x13\x35 + salt + encryptedhalf1 + encryptedhalf2 # (\x4E\xE3\x13\x35) gives the 'SeedE' prefix) encSeed = '\x4E\xE3\x13\x35' + salt + encryptedhalf1 + encryptedhalf2 check = hashlib.sha256(hashlib.sha256(encSeed).digest()).digest()[:4] return enc.b58encode(encSeed + check)
def encrypt(privK, Baddress, Saddress, passphrase):
"""
BIP0038 private key encryption, Non-EC
"""
# 1. take the first four bytes of SHA256(SHA256(address)) of it. Let's call this "addresshash".
addresshash = hashlib.sha256(hashlib.sha256(Baddress + Saddress).digest()).digest()[:4]
#2. Derive a key from the passphrase using scrypt
# a. Parameters: passphrase is the passphrase itself encoded in UTF-8.
# addresshash came from the earlier step, n=16384, r=8, p=8, length=64
# (n, r, p are provisional and subject to consensus)
key = scrypt.hash(passphrase, addresshash, 16384, 8, 8)
#Let's split the resulting 64 bytes in half, and call them derivedhalf1 and derivedhalf2.
derivedhalf1 = key[0:32]
derivedhalf2 = key[32:64]
#3. Do AES256Encrypt(bitcoinprivkey[0...15] xor derivedhalf1[0...15], derivedhalf2), call the 16-byte result encryptedhalf1
Aes = aes.Aes(derivedhalf2)
encryptedhalf1 = Aes.enc(enc.sxor(privK[:16], derivedhalf1[:16]))
#4. Do AES256Encrypt(bitcoinprivkey[16...31] xor derivedhalf1[16...31], derivedhalf2), call the 16-byte result encryptedhalf2
encryptedhalf2 = Aes.enc(enc.sxor(privK[16:32], derivedhalf1[16:32]))
#5. The encrypted private key is the Base58Check-encoded concatenation of the following, which totals 39 bytes without Base58 checksum:
# 0x01 0x42 + flagbyte + salt + encryptedhalf1 + encryptedhalf2
flagbyte = chr(0b11100000) # 11 no-ec 1 compressed-pub 00 future 0 ec only 00 future
privkey = ('\x01\x42' + flagbyte + addresshash + encryptedhalf1 + encryptedhalf2)
check = hashlib.sha256(hashlib.sha256(privkey).digest()).digest()[:4]
return enc.b58encode(privkey + check)
def confirmationcode(flagbyte, addresshash, ownerentropy, factorb,
derivedhalf1, derivedhalf2):
"""
The party generating the Bitcoin address has the option to return a confirmation code back to owner which allows owner
to independently verify that he has been given a Bitcoin address that actually depends on his passphrase,
and to confirm the lot and sequence numbers (if applicable).
This protects owner from being given a Bitcoin address by the second party that is unrelated to the key derivation and possibly spendable by the second party.
If a Bitcoin address given to owner can be successfully regenerated through the confirmation process,
owner can be reasonably assured that any spending without the passphrase is infeasible.
This confirmation code is 75 characters starting with "cfrm38".
To generate it, we need flagbyte, addresshash, ownerentropy, factorb, derivedhalf1 and derivedhalf2 from the original encryption operation.
"""
#1. ECMultiply factorb by G, call the result pointb. The result is 33 bytes (compressed key format).
pub = elip.base10_multiply(elip.G, enc.decode(factorb, 256))
pointb = ('0' + str(2 + (pub[1] % 2)) + enc.encode(pub[0], 16, 64))[:33]
#2. The first byte is 0x02 or 0x03. XOR it by (derivedhalf2[31] & 0x01), call the resulting byte pointbprefix.
pointbprefix = enc.sxor(pointb[:1], str(derivedhalf2[31]) + '\x01')
#3. Do AES256Encrypt(pointb[1...16] xor derivedhalf1[0...15], derivedhalf2) and call the result pointbx1.
Aes = aes.Aes(derivedhalf2)
pointbx1 = Aes.enc(enc.sxor(pointb[1:17], derivedhalf1[0:16]))
#4. Do AES256Encrypt(pointb[17...32] xor derivedhalf1[16...31], derivedhalf2) and call the result pointbx2.
pointbx2 = Aes.enc(enc.sxor(pointb[17:33], derivedhalf1[16:32]))
#5. Concatenate pointbprefix + pointbx1 + pointbx2 (total 33 bytes) and call the result encryptedpointb.
encryptedpointb = pointbprefix + pointbx1 + pointbx2
#6. The result is a Base58Check-encoded concatenation of the following:
#0x64 0x3B 0xF6 0xA8 0x9A + flagbyte + addresshash + ownerentropy + encryptedpointb
inp_fmtd = '\x64\x3B\xF6\xA8\x9A' + flagbyte + addresshash + ownerentropy + encryptedpointb
check = hashlib.sha256(hashlib.sha256(inp_fmtd).digest()).digest()[:4]
return enc.b58encode(inp_fmtd + check)
def decrypt(encrypted_privkey, passphrase, p):
#1. Collect encrypted private key and passphrase from user.
# passed as parameters
#2. Derive passfactor using scrypt with ownersalt and the user's passphrase and use it to recompute passpoint
d = enc.b58decode(encrypted_privkey)
d = d[2:]
flagbyte = d[0:1]
d = d[1:]
addresshash = d[0:4]
d = d[4:-4]
#3. Derive decryption key for seedb using scrypt with passpoint, addresshash, and ownersalt
key = scrypt.hash(passphrase, addresshash, 16384, 8, p)
derivedhalf1 = key[0:32]
derivedhalf2 = key[32:64]
encryptedhalf1 = d[0:16]
encryptedhalf2 = d[16:32]
#4. Decrypt encryptedpart2 using AES256Decrypt to yield the last 8 bytes of seedb and the last 8 bytes of encryptedpart1.
Aes = aes.Aes(derivedhalf2)
decryptedhalf2 = Aes.dec(encryptedhalf2)
#5. Decrypt encryptedpart1 to yield the remainder of seedb.
decryptedhalf1 = Aes.dec(encryptedhalf1)
priv = decryptedhalf1 + decryptedhalf2
priv = binascii.unhexlify('%064x' %
(long(binascii.hexlify(priv), 16)
^ long(binascii.hexlify(derivedhalf1), 16)))
return priv, addresshash
def encrypt(pub_address, passphrase):
"""
Encrypt the public address
"""
#1 base 58 decode the public address
address = enc.b58decode(pub_address)
#2. Take a hash of the decoded address to act as a scrypt salt
salt = hashlib.sha256(hashlib.sha256(address).digest()).digest()[:4]
#2. Derive a key from the passphrase using scrypt
key = scrypt.hash(passphrase, salt, 16384, 8, 8)
#3. Split the key into half 1 and half 2
derivedhalf1 = key[0:32]
derivedhalf2 = key[32:64]
#4 AES encrypt address halves as per bip38
halflength = int(math.floor(len(address) / 2))
Aes = aes.Aes(derivedhalf2)
#for Aes encryption, string needs to have length = 16
xorhalf1 = enc.sxor(address[:halflength], derivedhalf1[:16]).ljust(16, '0')
xorhalf2 = enc.sxor(address[halflength:],
derivedhalf1[16:32]).ljust(16, '0')
encryptedhalf1 = Aes.enc(xorhalf1)
encryptedhalf2 = Aes.enc(xorhalf2)
#5. The encrypted private key is the Base58Check-encoded concatenation of the following
# \x78\x8e\xa3\x69\xb6 + address_length + salt + encryptedhalf1 + encryptedhalf2
encAddress = '\x78\x8e\xa3\x69\xb6' + chr(
len(address)) + salt + encryptedhalf1 + encryptedhalf2
check = hashlib.sha256(hashlib.sha256(encAddress).digest()).digest()[:4]
return enc.b58encode(encAddress + check)
def confirmcode(confirmationcode, passphrase):
"""
A confirmation tool, given a passphrase and a confirmation code, can recalculate the address, verify the address hash, and then assert the following:
"It is confirmed that Bitcoin address address depends on this passphrase".
To recalculate the address:
"""
#decode the confirmationcode to give addresshash, ownerentropy and encryptedpointb
data = enc.b58decode(confirmationcode)
checksum = data[-4:]
hash = hashlib.sha256(hashlib.sha256(data[:-4]).digest()).digest()[:4]
assert hash == checksum
addresshash = data[6:10]
ownerentropy = data[10:18]
encryptedpointb = data[18:51]
pointbx1 = encryptedpointb[1:17]
pointbx2 = encryptedpointb[17:33]
#1. Derive passfactor using scrypt with ownerentropy and the user's passphrase and use it to recompute passpoint
passfactor = scrypt.hash(passphrase, ownerentropy, 16384, 8, 8, 32)
pub = elip.base10_multiply(elip.G, enc.decode(passfactor, 256))
passpoint = ('0' + str(2 + (pub[1] % 2)) +
enc.encode(pub[0], 16, 64)).decode('hex')
#2. Derive decryption key for pointb using scrypt with passpoint, addresshash, and ownerentropy
key = scrypt.hash(passpoint, addresshash + ownerentropy, 1024, 1, 1, 64)
derivedhalf1 = key[0:32]
derivedhalf2 = key[32:64]
#3. Decrypt encryptedpointb to yield pointb
Aes = aes.Aes(derivedhalf2)
decryptedhalf1 = Aes.dec(pointbx1)
decryptedhalf2 = Aes.dec(pointbx2)
pointb = '0' + decryptedhalf1 + decryptedhalf2
pointb = binascii.unhexlify('%064x' %
(long(binascii.hexlify(pointb), 16)
^ long(binascii.hexlify(derivedhalf1), 16)))
#4. ECMultiply pointb by passfactor. Use the resulting EC point as a public key and hash it into address using either compressed or uncompressed public key
# methodology as specified in flagbyte.
pub = elip.base10_multiply(pointb, enc.decode(passfactor, 256))
print('pub[0] = ' + str(pub[0]))
print('pub[1] = ' + str(pub[1]))
publicKey = ('0' + str(2 + (pub[1] % 2)) + enc.encode(pub[0], 16, 64))
print('pubKey = ' + publicKey)
generatedaddress = address.publicKey2Address(publicKey)
print('generatedaddress = ' + generatedaddress)
#print(hashlib.sha256(hashlib.sha256(generatedaddress).digest()).digest()[:4])
#print(addresshash)
#assert hashlib.sha256(hashlib.sha256(generatedaddress).digest()).digest()[:4] == addresshash
return
def confirmcode(confirmationcode, passphrase):
"""
A confirmation tool, given a passphrase and a confirmation code, can recalculate the address, verify the address hash, and then assert the following:
"It is confirmed that Bitcoin address address depends on this passphrase".
If applicable: "The lot number is lotnumber and the sequence number is sequencenumber."
To recalculate the address:
"""
#decode the confirmationcode to give addresshash, ownerentropy and encryptedpointb
data = enc.encode(enc.decode(confirmationcode, 58), 256)
assert hashlib.sha256(hashlib.sha256(
data[:-4]).digest()).digest()[:4] == data[-4:]
addresshash = data[6:10]
ownerentropy = data[10:18]
encryptedpointb = data[18:51]
pointbprefix = encryptedpointb[:1]
pointbx1 = encryptedpointb[1:17]
pointbx2 = encryptedpointb[17:]
#1. Derive passfactor using scrypt with ownerentropy and the user's passphrase and use it to recompute passpoint
prefactor = scrypt.hash(passphrase, ownerentropy[:4], 16384, 8, 8, 32)
passfactor = hashlib.sha256(
hashlib.sha256(prefactor + ownerentropy).digest()).digest()
pub = elip.base10_multiply(elip.G, enc.decode(passfactor, 256))
passpoint = ('0' + str(2 + (pub[1] % 2)) +
enc.encode(pub[0], 16, 64)).decode('hex')
#2. Derive decryption key for pointb using scrypt with passpoint, addresshash, and ownerentropy
key = scrypt.hash(passpoint, addresshash + ownerentropy, 1024, 1, 1, 64)
derivedhalf1 = key[0:32]
derivedhalf2 = key[32:64]
#3. Decrypt encryptedpointb to yield pointb
Aes = aes.Aes(derivedhalf2)
pointb = pointbprefix + Aes.dec(pointbx1) + Aes.dec(pointbx2)
print('pointb = ' + pointb.encode('hex'))
#4. ECMultiply pointb by passfactor. Use the resulting EC point as a public key and hash it into address using either compressed or uncompressed public key
# methodology as specifid in flagbyte.
pub = elip.base10_multiply(enc.decode(passfactor, 256),
enc.decode(pointb, 256))
privK = ('0' + str(2 + (pub[1] % 2)) + enc.encode(pub[0], 16, 64))
generatedaddress = address.publicKey2Address(privK)
#print(generatedaddress)
#print(hashlib.sha256(hashlib.sha256(generatedaddress).digest()).digest()[:4])
#print(addresshash)
#assert hashlib.sha256(hashlib.sha256(generatedaddress).digest()).digest()[:4] == addresshash
return
def decrypt(encSeed, passphrase):
"""
Decrypt an Electrum seed encrypted with the above method
"""
#1. Base 58 decrypt the encrypted key
# get the two encrypted halves, the check and the salt
decSeed = enc.b58decode(encSeed)
check = decSeed[-4:]
#check that it's not been tampered with
if check != hashlib.sha256(hashlib.sha256(
decSeed[:-4]).digest()).digest()[:4]:
return False, 'checksum'
salt = decSeed[4:8]
encryptedhalfs = decSeed[8:len(decSeed) - 4]
encryptedhalf1 = encryptedhalfs[0:int(math.floor(len(encryptedhalfs) / 2))]
encryptedhalf2 = encryptedhalfs[int(math.floor(len(encryptedhalfs) / 2)):]
#2. Derive the decryption key using scrypt
key = scrypt.hash(passphrase, salt, 16384, 8, 8)
derivedhalf1 = key[0:32]
derivedhalf2 = key[32:64]
#3. Decrypt the encrypted halves
Aes = aes.Aes(derivedhalf2)
decryptedhalf1 = Aes.dec(encryptedhalf1)
decryptedhalf2 = Aes.dec(encryptedhalf2)
#4 . xor them with the two halves of derivedhalf1 to get the original values
half1 = enc.sxor(decryptedhalf1, derivedhalf1[:16])
half2 = enc.sxor(decryptedhalf2, derivedhalf1[16:32])
#5. build the seed and check it against the check hash
seed = half1 + half2
if salt != hashlib.sha256(hashlib.sha256(seed).digest()).digest()[:4]:
return False, 'salt'
#6. encode the seed as an Electrum Mnemonic list
mn = mn_encode(str(seed))
#6 . return the mnemonic as a single string
seed = ''
for word in mn:
seed += word + ' '
return True, seed
def decrypt(enc_address, passphrase):
"""
Decrypt an Public Address encrypted with the above method
"""
#1. Base 58 decrypt the encrypted key
# get the two encrypted halves, the check and the salt
dec_address = enc.b58decode(enc_address)
check = dec_address[-4:]
#check that it's not been tampered with
if check != hashlib.sha256(hashlib.sha256(
dec_address[:-4]).digest()).digest()[:4]:
return False, 'checksum'
length = ord(dec_address[5:6])
halflength = int(math.floor(length / 2))
salt = dec_address[6:10]
encryptedhalfs = dec_address[10:len(dec_address) - 4]
encryptedhalf1 = encryptedhalfs[:16]
encryptedhalf2 = encryptedhalfs[16:]
#2. Derive the decryption key using scrypt
key = scrypt.hash(passphrase, salt, 16384, 8, 8)
derivedhalf1 = key[0:32]
derivedhalf2 = key[32:64]
#3. Aes decrypt the encrypted halves
Aes = aes.Aes(derivedhalf2)
xorhalf1 = Aes.dec(encryptedhalf1)
xorhalf2 = Aes.dec(encryptedhalf2)
#4 . xor them with the two halves of derivedhalf1 to get the original values
half1 = enc.sxor(xorhalf1[:halflength], derivedhalf1[:16])
half2 = enc.sxor(xorhalf2[:(length - halflength)], derivedhalf1[16:32])
#5. build the address and check it against the check hash
pub_address = half1 + half2
if salt != hashlib.sha256(
hashlib.sha256(pub_address).digest()).digest()[:4]:
return False, 'salt'
#6. return the address as a single string
return True, enc.b58encode(pub_address)
def intermediate2privK(intermediate_passphrase_string):
"""
Steps to create new encrypted private keys given intermediate_passphrase_string from owner
(so we have ownerentropy, and passpoint, but we do not have passfactor or the passphrase):
"""
#get ownerentropy and passpoint from the intermediate key
#check the checksum en route
decstring = enc.b58decode(intermediate_passphrase_string)
checksum = decstring[-4:]
if checksum != hashlib.sha256(hashlib.sha256(
decstring[:-4]).digest()).digest()[:4]:
return False, 'checksum'
decodedstring = decstring[:-4]
ownerentropy = decodedstring[8:16]
passpoint = decodedstring[-33:]
print(passpoint)
#1. Set flagbyte.
#Turn on bit 0x20 if the Bitcoin address will be formed by hashing the compressed public key (optional, saves space, but many Bitcoin implementations aren't compatible with it)
#Turn on bit 0x04 if ownerentropy contains a value for lotsequence.
#(While it has no effect on the keypair generation process, the decryption process needs this flag to know how to process ownerentropy)
flagbyte = chr(
0b00100000
) # 00 EC 1 compressed 00 future 0 has no lotsequence 00 future
#2. Generate 24 random bytes, call this seedb. Take SHA256(SHA256(seedb)) to yield 32 bytes, call this factorb.
seedb = os.urandom(24)
seedb = b'ABCDEFGHIJKLMNOPQRSTUVWX'
#seedb = bytearray(b'ABCDEFGHIJKLMNOPQRSTUVWX')
#for c in seedb: print(c)
factorb = hashlib.sha256(hashlib.sha256(seedb).digest()).digest()
#3. ECMultiply passpoint by factorb.
pub = elip.base10_multiply(enc.decode(passpoint, 256),
enc.decode(factorb, 256))
#4. Use the resulting EC point as a public key and hash it into a Bitcoin address using either compressed or uncompressed public key methodology
# (specify which methodology is used inside flagbyte).
# This is the generated Bitcoin address, call it generatedaddress.
publicKey = ('0' + str(2 + (pub[1] % 2)) + enc.encode(pub[0], 16, 64))
generatedaddress = address.publicKey2Address(
publicKey) ## TODO Remember to add in the currency details here
#5. Take the first four bytes of SHA256(SHA256(generatedaddress)) and call it addresshash.
addresshash = hashlib.sha256(
hashlib.sha256(generatedaddress).digest()).digest()[:4]
#6. Now we will encrypt seedb. Derive a second key from passpoint using scrypt
#Parameters: passphrase is passpoint provided from the first party (expressed in binary as 33 bytes).
# salt is addresshash + ownerentropy, n=1024, r=1, p=1, length=64. The "+" operator is concatenation.
encseedb = scrypt.hash(passpoint, addresshash + ownerentropy, 1024, 1, 1,
64)
#7. Split the result into two 32-byte halves and call them derivedhalf1 and derivedhalf2.
derivedhalf1 = encseedb[0:32]
derivedhalf2 = encseedb[32:64]
#8. Do AES256Encrypt(seedb[0...15] xor derivedhalf1[0...15], derivedhalf2), call the 16-byte result encryptedpart1
Aes = aes.Aes(derivedhalf2)
encryptedpart1 = Aes.enc(enc.sxor(seedb[:16], derivedhalf1[:16]))
#9. Do AES256Encrypt((encryptedpart1[8...15] + seedb[16...23]) xor derivedhalf1[16...31], derivedhalf2), call the 16-byte result encryptedpart2.
# The "+" operator is concatenation.
encryptedpart2 = Aes.enc(
enc.sxor(encryptedpart1[8:16] + seedb[16:24], derivedhalf1[16:32]))
#10. The encrypted private key is the Base58Check-encoded concatenation of the following, which totals 39 bytes without Base58 checksum:
#0x01 0x43 + flagbyte + addresshash + ownerentropy + encryptedpart1[0...7] + encryptedpart2
input = '\x01\x43' + flagbyte + addresshash + ownerentropy + encryptedpart1[
0:8] + encryptedpart2
checksum = hashlib.sha256(hashlib.sha256(input).digest()).digest()[:4]
BIPKey = enc.b58encode(input + checksum)
cnfrmcode = confirmationcode(flagbyte, addresshash, ownerentropy, factorb,
derivedhalf1, derivedhalf2)
return BIPKey, generatedaddress, cnfrmcode
