text: #!/usr/bin/python
  from .py2specials import *
  from .py3specials import *
  import binascii
  import hashlib
  import re
  import base64
  import time
  import random
  import hmac
  from .ripemd import *
  
  # Elliptic curve parameters (secp256k1)
  
  P = 2**256 - 2**32 - 977
  #Highest N for prikey = 0xfffffffffffffffffffffffffffffffebaaedce6af48a03bbfd25e8cd0364141
  N = 115792089237316195423570985008687907852837564279074904382605163141518161494337
  A = 0
  B = 7
  Gx = 55066263022277343669578718895168534326250603453777594175500187360389116729240
  Gy = 32670510020758816978083085130507043184471273380659243275938904335757337482424
  G = (Gx, Gy)
  
  
  def change_curve(p, n, a, b, gx, gy):
      global P, N, A, B, Gx, Gy, G
      P, N, A, B, Gx, Gy = p, n, a, b, gx, gy
      G = (Gx, Gy)
  
  
  def getG():
      return G
  
  # Extended Euclidean Algorithm
  
  
  def inv(a, n):
      if a == 0:
          return 0
      lm, hm = 1, 0
      low, high = a % n, n
      while low > 1:
          r = high//low
          nm, new = hm-lm*r, high-low*r
          lm, low, hm, high = nm, new, lm, low
      return lm % n
  
  
  
  # JSON access (for pybtctool convenience)
  
  
  def access(obj, prop):
      if isinstance(obj, dict):
          if prop in obj:
              return obj[prop]
          elif '.' in prop:
              return obj[float(prop)]
          else:
              return obj[int(prop)]
      else:
          return obj[int(prop)]
  
  
  def multiaccess(obj, prop):
      return [access(o, prop) for o in obj]
  
  
  def slice(obj, start=0, end=2**200):
      return obj[int(start):int(end)]
  
  
  def count(obj):
      return len(obj)
  
  _sum = sum
  
  
  def sum(obj):
      return _sum(obj)
  
  
  def isinf(p):
      return p[0] == 0 and p[1] == 0
  
  
  def to_jacobian(p):
      o = (p[0], p[1], 1)
      return o
  
  
  def jacobian_double(p):
      if not p[1]:
          return (0, 0, 0)
      ysq = (p[1] ** 2) % P
      S = (4 * p[0] * ysq) % P
      M = (3 * p[0] ** 2 + A * p[2] ** 4) % P
      nx = (M**2 - 2 * S) % P
      ny = (M * (S - nx) - 8 * ysq ** 2) % P
      nz = (2 * p[1] * p[2]) % P
      return (nx, ny, nz)
  
  
  def jacobian_add(p, q):
      if not p[1]:
          return q
      if not q[1]:
          return p
      U1 = (p[0] * q[2] ** 2) % P
      U2 = (q[0] * p[2] ** 2) % P
      S1 = (p[1] * q[2] ** 3) % P
      S2 = (q[1] * p[2] ** 3) % P
      if U1 == U2:
          if S1 != S2:
              return (0, 0, 1)
          return jacobian_double(p)
      H = U2 - U1
      R = S2 - S1
      H2 = (H * H) % P
      H3 = (H * H2) % P
      U1H2 = (U1 * H2) % P
      nx = (R ** 2 - H3 - 2 * U1H2) % P
      ny = (R * (U1H2 - nx) - S1 * H3) % P
      nz = (H * p[2] * q[2]) % P
      return (nx, ny, nz)
  
  
  def from_jacobian(p):
      z = inv(p[2], P)
      return ((p[0] * z**2) % P, (p[1] * z**3) % P)
  
  
  def jacobian_multiply(a, n):
      if a[1] == 0 or n == 0:
          return (0, 0, 1)
      if n == 1:
          return a
      if n < 0 or n >= N:
          return jacobian_multiply(a, n % N)
      if (n % 2) == 0:
          return jacobian_double(jacobian_multiply(a, n//2))
      if (n % 2) == 1:
          return jacobian_add(jacobian_double(jacobian_multiply(a, n//2)), a)
  
  
  def fast_multiply(a, n):
      return from_jacobian(jacobian_multiply(to_jacobian(a), n))
  
  
  def fast_add(a, b):
      return from_jacobian(jacobian_add(to_jacobian(a), to_jacobian(b)))
  
  # Functions for handling pubkey and privkey formats
  
  
  def get_pubkey_format(pub):
      if is_python2:
          two = '\x02'
          three = '\x03'
          four = '\x04'
      else:
          two = 2
          three = 3
          four = 4
  
      if isinstance(pub, (tuple, list)): return 'decimal'
      elif len(pub) == 65 and pub[0] == four: return 'bin'
      elif len(pub) == 130 and pub[0:2] == '04': return 'hex'
      elif len(pub) == 33 and pub[0] in [two, three]: return 'bin_compressed'
      elif len(pub) == 66 and pub[0:2] in ['02', '03']: return 'hex_compressed'
      elif len(pub) == 64: return 'bin_electrum'
      elif len(pub) == 128: return 'hex_electrum'
      else: raise Exception("Pubkey not in recognized format")
  
  
  def encode_pubkey(pub, formt):
      if not isinstance(pub, (tuple, list)):
          pub = decode_pubkey(pub)
      if formt == 'decimal': return pub
      elif formt == 'bin': return b'\x04' + encode(pub[0], 256, 32) + encode(pub[1], 256, 32)
      elif formt == 'bin_compressed':
          return from_int_to_byte(2+(pub[1] % 2)) + encode(pub[0], 256, 32)
      elif formt == 'hex': return '04' + encode(pub[0], 16, 64) + encode(pub[1], 16, 64)
      elif formt == 'hex_compressed':
          return '0'+str(2+(pub[1] % 2)) + encode(pub[0], 16, 64)
      elif formt == 'bin_electrum': return encode(pub[0], 256, 32) + encode(pub[1], 256, 32)
      elif formt == 'hex_electrum': return encode(pub[0], 16, 64) + encode(pub[1], 16, 64)
      else: raise Exception("Invalid format!")
  
  
  def decode_pubkey(pub, formt=None):
      if not formt: formt = get_pubkey_format(pub)
      if formt == 'decimal': return pub
      elif formt == 'bin': return (decode(pub[1:33], 256), decode(pub[33:65], 256))
      elif formt == 'bin_compressed':
          x = decode(pub[1:33], 256)
          beta = pow(int(x*x*x+A*x+B), int((P+1)//4), int(P))
          y = (P-beta) if ((beta + from_byte_to_int(pub[0])) % 2) else beta
          return (x, y)
      elif formt == 'hex': return (decode(pub[2:66], 16), decode(pub[66:130], 16))
      elif formt == 'hex_compressed':
          return decode_pubkey(safe_from_hex(pub), 'bin_compressed')
      elif formt == 'bin_electrum':
          return (decode(pub[:32], 256), decode(pub[32:64], 256))
      elif formt == 'hex_electrum':
          return (decode(pub[:64], 16), decode(pub[64:128], 16))
      else: raise Exception("Invalid format!")
  
  def get_privkey_format(priv):
      if isinstance(priv, int_types): return 'decimal'
      elif len(priv) == 32: return 'bin'
      elif len(priv) == 33: return 'bin_compressed'
      elif len(priv) == 64: return 'hex'
      elif len(priv) == 66: return 'hex_compressed'
      else:
          bin_p = b58check_to_bin(priv)
          if len(bin_p) == 32: return 'wif'
          elif len(bin_p) == 33: return 'wif_compressed'
          else: raise Exception("WIF does not represent privkey")
  
  def encode_privkey(priv, formt, vbyte=128):
      if not isinstance(priv, int_types):
          return encode_privkey(decode_privkey(priv), formt, vbyte)
      if formt == 'decimal': return priv
      elif formt == 'bin': return encode(priv, 256, 32)
      elif formt == 'bin_compressed': return encode(priv, 256, 32)+b'\x01'
      elif formt == 'hex': return encode(priv, 16, 64)
      elif formt == 'hex_compressed': return encode(priv, 16, 64)+'01'
      elif formt == 'wif':
          return bin_to_b58check(encode(priv, 256, 32), int(vbyte))
      elif formt == 'wif_compressed':
          return bin_to_b58check(encode(priv, 256, 32) + b'\x01', int(vbyte))
      else: raise Exception("Invalid format!")
  
  def decode_privkey(priv,formt=None):
      if not formt: formt = get_privkey_format(priv)
      if formt == 'decimal': return priv
      elif formt == 'bin': return decode(priv, 256)
      elif formt == 'bin_compressed': return decode(priv[:32], 256)
      elif formt == 'hex': return decode(priv, 16)
      elif formt == 'hex_compressed': return decode(priv[:64], 16)
      elif formt == 'wif': return decode(b58check_to_bin(priv),256)
      elif formt == 'wif_compressed':
          return decode(b58check_to_bin(priv)[:32],256)
      else: raise Exception("WIF does not represent privkey")
  
  def add_pubkeys(p1, p2):
      f1, f2 = get_pubkey_format(p1), get_pubkey_format(p2)
      return encode_pubkey(fast_add(decode_pubkey(p1, f1), decode_pubkey(p2, f2)), f1)
  
  def add_privkeys(p1, p2):
      f1, f2 = get_privkey_format(p1), get_privkey_format(p2)
      return encode_privkey((decode_privkey(p1, f1) + decode_privkey(p2, f2)) % N, f1)
  
  
  def mul_privkeys(p1, p2):
      f1, f2 = get_privkey_format(p1), get_privkey_format(p2)
      return encode_privkey((decode_privkey(p1, f1) * decode_privkey(p2, f2)) % N, f1)
  
  def multiply(pubkey, privkey):
      f1, f2 = get_pubkey_format(pubkey), get_privkey_format(privkey)
      pubkey, privkey = decode_pubkey(pubkey, f1), decode_privkey(privkey, f2)
      # http://safecurves.cr.yp.to/twist.html
      if not isinf(pubkey) and (pubkey[0]**3+B-pubkey[1]*pubkey[1]) % P != 0:
          raise Exception("Point not on curve")
      return encode_pubkey(fast_multiply(pubkey, privkey), f1)
  
  
  def divide(pubkey, privkey):
      factor = inv(decode_privkey(privkey), N)
      return multiply(pubkey, factor)
  
  
  def compress(pubkey):
      f = get_pubkey_format(pubkey)
      if 'compressed' in f: return pubkey
      elif f == 'bin': return encode_pubkey(decode_pubkey(pubkey, f), 'bin_compressed')
      elif f == 'hex' or f == 'decimal':
          return encode_pubkey(decode_pubkey(pubkey, f), 'hex_compressed')
  
  
  def decompress(pubkey):
      f = get_pubkey_format(pubkey)
      if 'compressed' not in f: return pubkey
      elif f == 'bin_compressed': return encode_pubkey(decode_pubkey(pubkey, f), 'bin')
      elif f == 'hex_compressed' or f == 'decimal':
          return encode_pubkey(decode_pubkey(pubkey, f), 'hex')
  
  
  def privkey_to_pubkey(privkey):
      f = get_privkey_format(privkey)
      privkey = decode_privkey(privkey, f)
      if privkey >= N:
          raise Exception("Invalid privkey")
      if f in ['bin', 'bin_compressed', 'hex', 'hex_compressed', 'decimal']:
          return encode_pubkey(fast_multiply(G, privkey), f)
      else:
          return encode_pubkey(fast_multiply(G, privkey), f.replace('wif', 'hex'))
  
  privtopub = privkey_to_pubkey
  
  
  def privkey_to_address(priv, magicbyte=0):
      return pubkey_to_address(privkey_to_pubkey(priv), magicbyte)
  privtoaddr = privkey_to_address
  
  
  def neg_pubkey(pubkey):
      f = get_pubkey_format(pubkey)
      pubkey = decode_pubkey(pubkey, f)
      return encode_pubkey((pubkey[0], (P-pubkey[1]) % P), f)
  
  
  def neg_privkey(privkey):
      f = get_privkey_format(privkey)
      privkey = decode_privkey(privkey, f)
      return encode_privkey((N - privkey) % N, f)
  
  def subtract_pubkeys(p1, p2):
      f1, f2 = get_pubkey_format(p1), get_pubkey_format(p2)
      k2 = decode_pubkey(p2, f2)
      return encode_pubkey(fast_add(decode_pubkey(p1, f1), (k2[0], (P - k2[1]) % P)), f1)
  
  
  def subtract_privkeys(p1, p2):
      f1, f2 = get_privkey_format(p1), get_privkey_format(p2)
      k2 = decode_privkey(p2, f2)
      return encode_privkey((decode_privkey(p1, f1) - k2) % N, f1)
  
  
  
  # Hashes
  
  
  def bin_hash160(string):
      intermed = hashlib.sha256(string).digest()
      digest = ''
      try:
          digest = hashlib.new('ripemd160', intermed).digest()
      except:
          digest = RIPEMD160(intermed).digest()
      return digest
  
  def hash160(string):
      return safe_hexlify(bin_hash160(string))
  
  def hex_to_hash160(s_hex):
      return hash160(binascii.unhexlify(s_hex))
  
  def bin_sha256(string):
      binary_data = string if isinstance(string, bytes) else bytes(string, 'utf-8')
      return hashlib.sha256(binary_data).digest()
  
  def sha256(string):
      return bytes_to_hex_string(bin_sha256(string))
  
  
  def bin_ripemd160(string):
      try:
          digest = hashlib.new('ripemd160', string).digest()
      except:
          digest = RIPEMD160(string).digest()
      return digest
  
  
  def ripemd160(string):
      return safe_hexlify(bin_ripemd160(string))
  
  
  def bin_dbl_sha256(s):
      bytes_to_hash = from_string_to_bytes(s)
      return hashlib.sha256(hashlib.sha256(bytes_to_hash).digest()).digest()
  
  
  def dbl_sha256(string):
      return safe_hexlify(bin_dbl_sha256(string))
  
  
  def bin_slowsha(string):
      string = from_string_to_bytes(string)
      orig_input = string
      for i in range(100000):
          string = hashlib.sha256(string + orig_input).digest()
      return string
  
  
  def slowsha(string):
      return safe_hexlify(bin_slowsha(string))
  
  
  def hash_to_int(x):
      if len(x) in [40, 64]:
          return decode(x, 16)
      return decode(x, 256)
  
  
  def num_to_var_int(x):
      x = int(x)
      if x < 253: return from_int_to_byte(x)
      elif x < 65536: return from_int_to_byte(253)+encode(x, 256, 2)[::-1]
      elif x < 4294967296: return from_int_to_byte(254) + encode(x, 256, 4)[::-1]
      else: return from_int_to_byte(255) + encode(x, 256, 8)[::-1]
  
  
  # WTF, Electrum?
  def electrum_sig_hash(message):
      padded = b"\x18Bitcoin Signed Message:\n" + num_to_var_int(len(message)) + from_string_to_bytes(message)
      return bin_dbl_sha256(padded)
  
  
  def random_key():
      # Gotta be secure after that java.SecureRandom fiasco...
      entropy = random_string(32) \
          + str(random.randrange(2**256)) \
          + str(int(time.time() * 1000000))
      return sha256(entropy)
  
  
  def random_electrum_seed():
      #entropy = os.urandom(32) \ # fails in Python 3, hence copied from random_key()
      entropy = random_string(32) \
          + str(random.randrange(2**256)) \
          + str(int(time.time() * 1000000))
      return sha256(entropy)[:32]
  
  # Encodings
  
  def b58check_to_bin(inp):
      leadingzbytes = len(re.match('^1*', inp).group(0))
      data = b'\x00' * leadingzbytes + changebase(inp, 58, 256)
      assert bin_dbl_sha256(data[:-4])[:4] == data[-4:]
      return data[1:-4]
  
  
  def get_version_byte(inp):
      leadingzbytes = len(re.match('^1*', inp).group(0))
      data = b'\x00' * leadingzbytes + changebase(inp, 58, 256)
      assert bin_dbl_sha256(data[:-4])[:4] == data[-4:]
      return ord(data[0])
  
  
  def hex_to_b58check(inp, magicbyte=0):
      return bin_to_b58check(binascii.unhexlify(inp), magicbyte)
  
  
  def b58check_to_hex(inp):
      return safe_hexlify(b58check_to_bin(inp))
  
  def pubkey_to_hash(pubkey):
      if isinstance(pubkey, (list, tuple)):
          pubkey = encode_pubkey(pubkey, 'bin')
      if len(pubkey) in [66, 130]:
          return bin_hash160(binascii.unhexlify(pubkey))
      return bin_hash160(pubkey)
  
  def pubkey_to_hash_hex(pubkey):
      return safe_hexlify(pubkey_to_hash(pubkey))
  
  def pubkey_to_address(pubkey, magicbyte=0):
      pubkey_hash = pubkey_to_hash(pubkey)
      return bin_to_b58check(pubkey_hash, magicbyte)
  
  pubtoaddr = pubkey_to_address
  
  
  def is_privkey(priv):
      try:
          get_privkey_format(priv)
          return True
      except:
          return False
  
  def is_pubkey(pubkey):
      try:
          get_pubkey_format(pubkey)
          return True
      except:
          return False
  
  
  # EDCSA
  
  
  def encode_sig(v, r, s):
      vb, rb, sb = from_int_to_byte(v), encode(r, 256), encode(s, 256)
      
      result = base64.b64encode(vb+b'\x00'*(32-len(rb))+rb+b'\x00'*(32-len(sb))+sb)
      return result if is_python2 else str(result, 'utf-8')
  
  
  def decode_sig(sig):
      bytez = base64.b64decode(sig)
      return from_byte_to_int(bytez[0]), decode(bytez[1:33], 256), decode(bytez[33:], 256)
  
  # https://tools.ietf.org/html/rfc6979#section-3.2
  
  
  def deterministic_generate_k(msghash, priv):
      v = b'\x01' * 32
      k = b'\x00' * 32
      priv = encode_privkey(priv, 'bin')
      msghash = encode(hash_to_int(msghash), 256, 32)
      k = hmac.new(k, v+b'\x00'+priv+msghash, hashlib.sha256).digest()
      v = hmac.new(k, v, hashlib.sha256).digest()
      k = hmac.new(k, v+b'\x01'+priv+msghash, hashlib.sha256).digest()
      v = hmac.new(k, v, hashlib.sha256).digest()
      return decode(hmac.new(k, v, hashlib.sha256).digest(), 256)
  
  
  def ecdsa_raw_sign(msghash, priv):
  
      z = hash_to_int(msghash)
      k = deterministic_generate_k(msghash, priv)
  
      r, y = fast_multiply(G, k)
      s = inv(k, N) * (z + r*decode_privkey(priv)) % N
  
      v, r, s = 27+((y % 2) ^ (0 if s * 2 < N else 1)), r, s if s * 2 < N else N - s
      if 'compressed' in get_privkey_format(priv):
          v += 4
      return v, r, s
  
  
  def ecdsa_sign(msg, priv, coin):
      v, r, s = ecdsa_raw_sign(electrum_sig_hash(msg), priv)
      sig = encode_sig(v, r, s)
      assert ecdsa_verify(msg, sig, 
          privtopub(priv), coin), "Bad Sig!\t %s\nv = %d\n,r = %d\ns = %d" % (sig, v, r, s)
      return sig
  
  
  def ecdsa_raw_verify(msghash, vrs, pub):
      v, r, s = vrs
  
      w = inv(s, N)
      z = hash_to_int(msghash)
  
      u1, u2 = z*w % N, r*w % N
      x, y = fast_add(fast_multiply(G, u1), fast_multiply(decode_pubkey(pub), u2))
      return bool(r == x and (r % N) and (s % N))
  
  
  # For BitcoinCore, (msg = addr or msg = "") be default
  def ecdsa_verify_addr(msg, sig, addr, coin):
      assert coin.is_address(addr)
      Q = ecdsa_recover(msg, sig)
      magic = get_version_byte(addr)
      return (addr == coin.pubtoaddr(Q, int(magic))) or (addr == coin.pubtoaddr(compress(Q), int(magic)))
  
  
  def ecdsa_verify(msg, sig, pub, coin):
      if coin.is_address(pub):
          return ecdsa_verify_addr(msg, sig, pub, coin)
      return ecdsa_raw_verify(electrum_sig_hash(msg), decode_sig(sig), pub)
  
  
  def ecdsa_raw_recover(msghash, vrs):
      v, r, s = vrs
      x = r
      xcubedaxb = (x*x*x+A*x+B) % P
      beta = pow(xcubedaxb, (P+1)//4, P)
      y = beta if v % 2 ^ beta % 2 else (P - beta)
      # If xcubedaxb is not a quadratic residue, then r cannot be the x coord
      # for a point on the curve, and so the sig is invalid
      if (xcubedaxb - y*y) % P != 0 or not (r % N) or not (s % N):
          return False
      z = hash_to_int(msghash)
      Gz = jacobian_multiply((Gx, Gy, 1), (N - z) % N)
      XY = jacobian_multiply((x, y, 1), s)
      Qr = jacobian_add(Gz, XY)
      Q = jacobian_multiply(Qr, inv(r, N))
      Q = from_jacobian(Q)
  
      # if ecdsa_raw_verify(msghash, vrs, Q):
      return Q
      # return False
  
  
  def ecdsa_recover(msg, sig):
      v,r,s = decode_sig(sig)
      Q = ecdsa_raw_recover(electrum_sig_hash(msg), (v,r,s))
      return encode_pubkey(Q, 'hex_compressed') if v >= 31 else encode_pubkey(Q, 'hex')
  
  
  
  # add/subtract 
  def add(p1,p2):
      if is_privkey(p1):
          return add_privkeys(p1, p2)
      else:
          return add_pubkeys(p1, p2)
  
  def subtract(p1,p2):
      if is_privkey(p1):
          return subtract_privkeys(p1, p2)
      else:
          return subtract_pubkeys(p1, p2)
  
  hash160Low = b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00'
  hash160High = b'\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff'
  
  def magicbyte_to_prefix(magicbyte):
      first = bin_to_b58check(hash160Low, magicbyte=magicbyte)[0]
      last = bin_to_b58check(hash160High, magicbyte=magicbyte)[0]
      if first == last:
          return (first,)
      return (first, last)
  