release bitcoin seed security blog post

Author: functora

.github/workflows/pages.yml

@@ -0,0 +1,65 @@
+import os
+import sys
+import hashlib
+
+class Bip39Check(object):
+    def __init__(self, language):
+        self.radix = 2048
+        self.worddict = {}
+        self.wordlist = []
+
+        counter = 0
+
+        with open('%s/%s.txt' % (self._get_directory(), language), 'r') as file:
+            for w in file.readlines():
+                word = w.strip() if sys.version < '3' else w.strip()
+                self.worddict[word] = counter
+                self.wordlist.append(word)
+                counter = counter + 1
+
+        if(len(self.worddict) != self.radix):
+            raise ValueError('Expecting %d words, not %d', self.radix, len(self.worddict))
+
+    @classmethod
+    def _get_directory(cls):
+        return os.path.dirname(__file__)
+
+    def _check_size(self, phrase):
+        self.size = len(phrase) + 1
+        if (self.size % 3 != 0):
+            raise ValueError('Expecting 11 or 23 words')
+
+    def _compute_entropy(self, phrase):
+        self.entropy = 0
+        for w in phrase:
+            idx = self.worddict[w]
+            self.entropy = (self.entropy << 11) + idx
+        return self.entropy
+
+    def _scan(self):
+        checksum_bits = self.size // 3
+        entropy_size = (self.size * 11 - checksum_bits) // 8 # Fixed entropy string length
+        entropy_to_fill = 11 - checksum_bits
+        entropy_base = self.entropy << (entropy_to_fill)
+
+        for i in range(0, 2 ** entropy_to_fill):
+            entropy_candidate = entropy_base | i
+            entropy_str = (entropy_candidate).to_bytes(entropy_size, 'big')
+            hash = (hashlib.sha256(entropy_str).digest()[0])
+            checksum = hash >> (8 - checksum_bits)
+            final_word_idx = (i << checksum_bits) + checksum
+            checkword = self.wordlist[final_word_idx]
+            print (checkword)
+
+
+def main():
+    m = Bip39Check('english')
+    print("Enter the 23 words: ")
+    phrase = sys.stdin.readline().split()
+    m._check_size(phrase)
+    m._compute_entropy(phrase)
+    print("___________________________\nThese are your 8 candidate words, select any one of these for the 24th word.\n")
+    m._scan()
+
+if __name__ == '__main__':
+    main()