Generate Monero address

Monero

Generate Monero address from the root private key using plain old Python, Edwards curve's ed25519 implementation, Keccak-256 hashing and Monero's Base58 encoding.

Overview

Very simple Python code using the original Edwards elliptic curve (https://ed25519.cr.yp.to/python/ed25519.py) Python2 implementation.

  sk = 50150511263649120662242166448273279564834046212138956557558374591624601073410
  sk_hex = '%x' % sk
  print('private spend key: ' + sk_hex)

  import ed25519
  hexdigest = keccak(int_to_bin(sk))
  vk = bytes_to_int(hex_to_bytes(reverse(hexdigest)))
  vk %= ed25519.l
  vk_hex = reverse(bytes_to_hex(int_to_bytes(vk)))
  print('private view key: ' + vk_hex)

  Ps = publickey(sk_hex)
  ps = bin_to_hex(Ps)
  print('public spend key: ' + ps)

  Pv = publickey(vk_hex)
  pv = bin_to_hex(Pv)
  print('public view key: ' + pv)

  network = '12'
  data = network + ps + pv
  hexdigest = keccak(hex_to_bin(data))
  payload = data + hexdigest[0:8]
  address = base58(payload)
  print('address: ' + address)
private spend key: 6ee02ef8647856f4080882a1ec4fabee19ec047ca24d3abb13c0ce589a46f702
private view key: fba03c096736c326b072fe44fc5c2868009986fb7e89e64bfd52f071d7e9b307
public spend key: 287fe37fc3c6b9309cacb2ea3882aed8b01a4e00343b6a0aa7cac956a5ed6011
public view key: 36f877980a7916f5f293b6986d0099dbb46b82b9f8d2ff61fb12422b507260e6
address: 43A8A4fqgD698bedTnjaqBdF9MgHEiiCq2nNXNMtqzNj3t1Fv2VsDc9i8zyFh6srcgdkQs5bhpwrvHPY646xu8ijT3Bdxse

Please read step by step details below.

0. Private key

Just a very big number.

  k = 50150511263649120662242166448273279564834046212138956557558374591624601073410
  print(hex(k))
0x6ee02ef8647856f4080882a1ec4fabee19ec047ca24d3abb13c0ce589a46f702L

1. Private spend key

Spend key is just the root private key in hex.

  sk = k
  sk_hex = '%x' % sk
  print(sk_hex)
6ee02ef8647856f4080882a1ec4fabee19ec047ca24d3abb13c0ce589a46f702

2. Private view key

To calculate private view key we need to introduce a few helper methods to transform from int/hex to bytes and vice-versa. We also need Keccak hashing function.

  def bytes_to_int(bin):
    return reduce(lambda r, n: r * 256 + n, [int(c) for c in bin])
  def int_to_bytes(value):
    return list(reversed([int(value >> (i * 8) & 0xff) for i in range(32)]))
  def int_to_bin(n):
    return ''.join([chr(b)for b in int_to_bytes(n)])

  def hex_to_bytes(hex):
    return map(lambda x: int(x, 16), split(hex))
  def bytes_to_hex(bytes):
    return ''.join(['%02x' % b for b in bytes])
  def bin_to_hex(bin):
    return ''.join(['%02x' % ord(c) for c in bin])
  def hex_to_bin(hex):
    return ''.join(chr(b) for b in hex_to_bytes(hex))

  def reverse(hex):
    return ''.join(reversed(split(hex)))
  def split(hex):
    return [hex[i*2:i*2+2] for i in range(32)]

  def keccak(bin):
    import sha3
    h = sha3.keccak_256()
    h.update(bin);
    return h.hexdigest()

The derivation logic is as follows:

  • hash the private spend key with Keccak hashing function (note that SHA3 != Keccak)

  • transform the hash digest to integer (little endian, mind the reverse method)

  • take modulo operation to reduce

  • and finally the resulting hex (little endian again) is our private view key

  import ed25519
  hexdigest = keccak(int_to_bin(sk))
  vk = bytes_to_int(hex_to_bytes(reverse(hexdigest)))
  vk %= ed25519.l
  vk_hex = reverse(bytes_to_hex(int_to_bytes(vk)))
  print(vk_hex)
fba03c096736c326b072fe44fc5c2868009986fb7e89e64bfd52f071d7e9b307

3. Public spend key

Public key is a point on Edwards25519 elliptic curve and key derivation is best explained here.

What our little publickey method does is as simple as:

  • transform private key hex to binary string

  • decode binary string into integer

  • execute elliptic curve multiplication P = a*B

  • encode result elliptic curve point into binary string

  def publickey(k_hex):
    k_bin = hex_to_bin(k_hex)
    a = ed25519.decodeint(k_bin)
    A = ed25519.scalarmult(ed25519.B, a)
    return ed25519.encodepoint(A)

  Ps = publickey(sk_hex)
  ps = bin_to_hex(Ps)
  print(ps)
287fe37fc3c6b9309cacb2ea3882aed8b01a4e00343b6a0aa7cac956a5ed6011

4. Public view key

Same elliptic curve multiplication here but instead of private spend key (sk_hex) we now use private view key (vk_hex).

  Pv = publickey(vk_hex)
  pv = bin_to_hex(Pv)
  print(pv)
36f877980a7916f5f293b6986d0099dbb46b82b9f8d2ff61fb12422b507260e6

5. Monero address

And finally, time to generate Monero address:

  • concatenate network byte, public spend key and public view key

  • take Keccak hashing

  • append checksum (first 4 bytes of hexdigest) to original data

  • base58 encoding

  def base58(hex):
    import base58
    return base58.encode(hex)

  network = '12'
  data = network + ps + pv
  hexdigest = keccak(hex_to_bin(data))
  payload = data + hexdigest[0:8]
  address = base58(payload)
  print(address)
43A8A4fqgD698bedTnjaqBdF9MgHEiiCq2nNXNMtqzNj3t1Fv2VsDc9i8zyFh6srcgdkQs5bhpwrvHPY646xu8ijT3Bdxse

Verification

You can use the following mnemonic seed and verify the address with https://xmr.llcoins.net/.

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Also mnemonic seed to private key derivation is a subject for another post.

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