B

Task/Bitcoin-address-validation/Python/bitcoin-address-validation-1.py

@@ -0,0 +1,20 @@
+from hashlib import sha256
+
+digits58 = '123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz'
+
+def decode_base58(bc, length):
+    n = 0
+    for char in bc:
+        n = n * 58 + digits58.index(char)
+    return n.to_bytes(length, 'big')
+
+def check_bc(bc):
+    bcbytes = decode_base58(bc, 25)
+    return bcbytes[-4:] == sha256(sha256(bcbytes[:-4]).digest()).digest()[:4]
+
+if __name__ == '__main__':
+    bc = '1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i'
+    assert check_bc(bc)
+    assert not check_bc( bc.replace('N', 'P', 1) )
+    assert check_bc('1111111111111111111114oLvT2')
+    assert check_bc("17NdbrSGoUotzeGCcMMCqnFkEvLymoou9j")

Task/Bitcoin-address-validation/Python/bitcoin-address-validation-2.py

@@ -0,0 +1,6 @@
+>>> n = 2491969579123783355964723219455906992268673266682165637887
+>>> length = 25
+>>> list( reversed(range(length)) )
+[24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0]
+>>> assert n.to_bytes(length, 'big') == bytes( (n >> i*8) & 0xff for i in reversed(range(length)))
+>>>