You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
122 lines
4.5 KiB
122 lines
4.5 KiB
# Copyright (c) 2017 Pieter Wuille
|
|
#
|
|
# Permission is hereby granted, free of charge, to any person obtaining a copy
|
|
# of this software and associated documentation files (the "Software"), to deal
|
|
# in the Software without restriction, including without limitation the rights
|
|
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
|
|
# copies of the Software, and to permit persons to whom the Software is
|
|
# furnished to do so, subject to the following conditions:
|
|
#
|
|
# The above copyright notice and this permission notice shall be included in
|
|
# all copies or substantial portions of the Software.
|
|
#
|
|
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
|
|
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
|
|
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
|
|
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
|
|
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
|
|
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
|
|
# THE SOFTWARE.
|
|
"""Reference implementation for Bech32 and segwit addresses."""
|
|
|
|
CHARSET = "qpzry9x8gf2tvdw0s3jn54khce6mua7l"
|
|
|
|
|
|
def bech32_polymod( values ):
|
|
"""Internal function that computes the Bech32 checksum."""
|
|
generator = [ 0x3B6A57B2, 0x26508E6D, 0x1EA119FA, 0x3D4233DD, 0x2A1462B3 ]
|
|
chk = 1
|
|
for value in values:
|
|
top = chk >> 25
|
|
chk = ( chk & 0x1FFFFFF ) << 5 ^ value
|
|
for i in range( 5 ):
|
|
chk ^= generator[ i ] if ( ( top >> i ) & 1 ) else 0
|
|
return chk
|
|
|
|
|
|
def bech32_hrp_expand( hrp ):
|
|
"""Expand the HRP into values for checksum computation."""
|
|
return [ ord( x ) >> 5 for x in hrp ] + [ 0
|
|
] + [ ord( x ) & 31 for x in hrp ]
|
|
|
|
|
|
def bech32_verify_checksum( hrp, data ):
|
|
"""Verify a checksum given HRP and converted data characters."""
|
|
return bech32_polymod( bech32_hrp_expand( hrp ) + data ) == 1
|
|
|
|
|
|
def bech32_create_checksum( hrp, data ):
|
|
"""Compute the checksum values given HRP and data."""
|
|
values = bech32_hrp_expand( hrp ) + data
|
|
polymod = bech32_polymod( values + [ 0, 0, 0, 0, 0, 0 ] ) ^ 1
|
|
return [ ( polymod >> 5 * ( 5 - i ) ) & 31 for i in range( 6 ) ]
|
|
|
|
|
|
def bech32_encode( hrp, data ):
|
|
"""Compute a Bech32 string given HRP and data values."""
|
|
combined = data + bech32_create_checksum( hrp, data )
|
|
return hrp + "1" + "".join( [ CHARSET[ d ] for d in combined ] )
|
|
|
|
|
|
def bech32_decode( bech ):
|
|
"""Validate a Bech32 string, and determine HRP and data."""
|
|
if ( any( ord( x ) < 33 or ord( x ) > 126 for x in bech
|
|
) ) or ( bech.lower() != bech and bech.upper() != bech ):
|
|
return ( None, None )
|
|
bech = bech.lower()
|
|
pos = bech.rfind( "1" )
|
|
if pos < 1 or pos + 7 > len( bech ) or len( bech ) > 90:
|
|
return ( None, None )
|
|
if not all( x in CHARSET for x in bech[ pos + 1 : ] ):
|
|
return ( None, None )
|
|
hrp = bech[ : pos ]
|
|
data = [ CHARSET.find( x ) for x in bech[ pos + 1 : ] ]
|
|
if not bech32_verify_checksum( hrp, data ):
|
|
return ( None, None )
|
|
return ( hrp, data[ :-6 ] )
|
|
|
|
|
|
def convertbits( data, frombits, tobits, pad = True ):
|
|
"""General power-of-2 base conversion."""
|
|
acc = 0
|
|
bits = 0
|
|
ret = []
|
|
maxv = ( 1 << tobits ) - 1
|
|
max_acc = ( 1 << ( frombits + tobits - 1 ) ) - 1
|
|
for value in data:
|
|
if value < 0 or ( value >> frombits ):
|
|
return None
|
|
acc = ( ( acc << frombits ) | value ) & max_acc
|
|
bits += frombits
|
|
while bits >= tobits:
|
|
bits -= tobits
|
|
ret.append( ( acc >> bits ) & maxv )
|
|
if pad:
|
|
if bits:
|
|
ret.append( ( acc << ( tobits - bits ) ) & maxv )
|
|
elif bits >= frombits or ( ( acc << ( tobits - bits ) ) & maxv ):
|
|
return None
|
|
return ret
|
|
|
|
|
|
def decode( hrp, addr ):
|
|
"""Decode a segwit address."""
|
|
hrpgot, data = bech32_decode( addr )
|
|
if hrpgot != hrp:
|
|
return ( None, None )
|
|
decoded = convertbits( data[ 1 : ], 5, 8, False )
|
|
if decoded is None or len( decoded ) < 2 or len( decoded ) > 40:
|
|
return ( None, None )
|
|
if data[ 0 ] > 16:
|
|
return ( None, None )
|
|
if data[ 0 ] == 0 and len( decoded ) != 20 and len( decoded ) != 32:
|
|
return ( None, None )
|
|
return ( data[ 0 ], decoded )
|
|
|
|
|
|
def encode( hrp, witver, witprog ):
|
|
"""Encode a segwit address."""
|
|
ret = bech32_encode( hrp, [ witver ] + convertbits( witprog, 8, 5 ) )
|
|
if decode( hrp, ret ) == ( None, None ):
|
|
return None
|
|
return ret
|
|
|