Create mnemonic.py

cryptofuzz/mnemonic.py

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+from __future__ import annotations
+import re
+import hashlib
+import hmac
+import itertools
+import secrets
+import typing as t
+import unicodedata
+from .assest import BIP39
+from functools import lru_cache
+from concurrent.futures import ThreadPoolExecutor
+
+PBKDF2_ROUNDS = 2048
+WORDS_LIST = [word.lower() for word in re.findall('[A-Z][a-z]*', BIP39)]
+WORDS_SET = set(WORDS_LIST)
+
+
+class ConfigurationError(Exception):
+    pass
+
+
+# Refactored code segments from <https://github.com/keis/base58>
+def b58encode(v: bytes) -> str:
+    alphabet = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz"
+
+    p, acc = 1, 0
+    for c in reversed(v):
+        acc += p * c
+        p = p << 8
+
+    string = ""
+    while acc:
+        acc, idx = divmod(acc, 58)
+        string = alphabet[idx: idx + 1] + string
+    return string
+
+
+class Mnemonic(object):
+    def __init__(self, language: str = "english", wordlist: list[str] | None = None):
+        self.radix = 2048
+        self.language = language
+
+        if wordlist is None:
+            wordlist = WORDS_LIST
+
+        if len(wordlist) != self.radix:
+            raise ConfigurationError(f"Wordlist must contain {self.radix} words.")
+
+        self.wordlist = wordlist
+        # Japanese must be joined by ideographic space
+        self.delimiter = "\u3000" if language == "japanese" else " "
+
+    @staticmethod
+    @lru_cache(maxsize=1024)
+    def normalize_string(txt: t.AnyStr) -> str:
+        if isinstance(txt, bytes):
+            utxt = txt.decode("utf8")
+        elif isinstance(txt, str):
+            utxt = txt
+        else:
+            raise TypeError("String value expected")
+
+        return unicodedata.normalize("NFKD", utxt)
+
+    def generate(self, strength: int = 128) -> str:
+        if strength not in [128, 160, 192, 224, 256]:
+            raise ValueError(
+                "Invalid strength value. Allowed values are [128, 160, 192, 224, 256]."
+            )
+        return self.to_mnemonic(secrets.token_bytes(strength // 8))
+
+    # Adapted from <http://tinyurl.com/oxmn476>
+    def to_entropy(self, words: list[str] | str) -> bytearray:
+        if not isinstance(words, list):
+            words = words.split(" ")
+        if len(words) not in [12, 15, 18, 21, 24]:
+            raise ValueError(
+                "Number of words must be one of the following: [12, 15, 18, 21, 24], but it is not (%d)."
+                % len(words)
+            )
+        # Look up all the words in the list and construct the
+        # concatenation of the original entropy and the checksum.
+        concatLenBits = len(words) * 11
+        concatBits = [False] * concatLenBits
+        word_index = 0
+        for word in words:
+            # Find the words index in the wordlist
+            ndx = self.wordlist.index(self.normalize_string(word))
+            if ndx < 0:
+                raise LookupError('Unable to find "%s" in word list.' % word)
+            # Set the next 11 bits to the value of the index.
+            for ii in range(11):
+                concatBits[(word_index * 11) + ii] = (ndx & (1 << (10 - ii))) != 0
+            word_index += 1
+        checksumLengthBits = concatLenBits // 33
+        entropyLengthBits = concatLenBits - checksumLengthBits
+        # Extract original entropy as bytes.
+        entropy = bytearray(entropyLengthBits // 8)
+        for ii in range(len(entropy)):
+            for jj in range(8):
+                if concatBits[(ii * 8) + jj]:
+                    entropy[ii] |= 1 << (7 - jj)
+        # Take the digest of the entropy.
+        hashBytes = hashlib.sha256(entropy).digest()
+        hashBits = list(
+            itertools.chain.from_iterable(
+                [c & (1 << (7 - i)) != 0 for i in range(8)] for c in hashBytes
+            )
+        )
+        # Check all the checksum bits.
+        for i in range(checksumLengthBits):
+            if concatBits[entropyLengthBits + i] != hashBits[i]:
+                raise ValueError("Failed checksum.")
+        return entropy
+
+    def to_mnemonic(self, data: bytes) -> str:
+        if len(data) not in [16, 20, 24, 28, 32]:
+            raise ValueError(
+                f"Data length should be one of the following: [16, 20, 24, 28, 32], but it is not {len(data)}."
+            )
+        h = hashlib.sha256(data).hexdigest()
+        b = (
+                bin(int.from_bytes(data, byteorder="big"))[2:].zfill(len(data) * 8)
+                + bin(int(h, 16))[2:].zfill(256)[: len(data) * 8 // 32]
+        )
+        result = []
+        for i in range(len(b) // 11):
+            idx = int(b[i * 11: (i + 1) * 11], 2)
+            result.append(self.wordlist[idx])
+        return self.delimiter.join(result)
+
+    def check(self, mnemonic: str) -> bool:
+        mnemonic_list = self.normalize_string(mnemonic).split(" ")
+        # list of valid mnemonic lengths
+        if len(mnemonic_list) not in [12, 15, 18, 21, 24]:
+            return False
+        if not set(mnemonic_list).issubset(WORDS_SET):
+            return False
+        try:
+            b = ''.join([bin(WORDS_LIST.index(word))[2:].zfill(11) for word in mnemonic_list])
+            l = len(b)
+            entropy_bits = l // 33 * 32
+            checksum_bits = l - entropy_bits
+            # Entropy Extraction Checksum
+            entropy = int(b[:entropy_bits], 2).to_bytes(entropy_bits // 8, byteorder="big")
+            hash_checksum = bin(int(hashlib.sha256(entropy).hexdigest(), 16))[2:].zfill(256)[:checksum_bits]
+            # Checksum Validation Check
+            return b[-checksum_bits:] == hash_checksum
+        except ValueError:
+            return False
+
+    def expand_word(self, prefix: str) -> str:
+        if prefix in self.wordlist:
+            return prefix
+        else:
+            matches = [word for word in self.wordlist if word.startswith(prefix)]
+            if len(matches) == 1:  # matched exactly one word in the wordlist
+                return matches[0]
+            else:
+                # exact match not found.
+                # this is not a validation routine, just return the input
+                return prefix
+
+    def expand(self, mnemonic: str) -> str:
+        return " ".join(map(self.expand_word, mnemonic.split(" ")))
+
+    @classmethod
+    def to_seed(cls, mnemonic: str, passphrase: str = "") -> bytes:
+        mnemonic = cls.normalize_string(mnemonic)
+        passphrase = cls.normalize_string(passphrase)
+        passphrase = "mnemonic" + passphrase
+        mnemonic_bytes = mnemonic.encode("utf-8")
+        passphrase_bytes = passphrase.encode("utf-8")
+        stretched = hashlib.pbkdf2_hmac(
+            "sha512", mnemonic_bytes, passphrase_bytes, PBKDF2_ROUNDS
+        )
+        return stretched[:64]
+
+    @staticmethod
+    def to_hd_master_key(seed: bytes, testnet: bool = False) -> str:
+        if len(seed) != 64:
+            raise ValueError("Provided seed should have length of 64")
+
+        # Compute HMAC-SHA512 of seed
+        seed = hmac.new(b"Bitcoin seed", seed, digestmod=hashlib.sha512).digest()
+
+        # Serialization format can be found at: https://github.com/bitcoin/bips/blob/master/bip-0032.mediawiki
+        # #serialization-format
+        xprv = b"\x04\x88\xad\xe4"  # Version for private mainnet
+        if testnet:
+            xprv = b"\x04\x35\x83\x94"  # Version for private testnet
+        xprv += b"\x00" * 9  # Depth, parent fingerprint, and child number
+        xprv += seed[32:]  # Chain code
+        xprv += b"\x00" + seed[:32]  # Master key
+
+        # Double hash using SHA256
+        hashed_xprv = hashlib.sha256(xprv).digest()
+        hashed_xprv = hashlib.sha256(hashed_xprv).digest()
+
+        # Append 4 bytes of checksum
+        xprv += hashed_xprv[:4]
+
+        # Return base58
+        return b58encode(xprv)
+
+    def check_multiple_mnemonics(self, mnemonics: list[str]) -> list[bool]:
+        """
+        Check multiple mnemonics for validity.
+
+        :param: mnemonics: list of mnemonics
+        :return: list of booleans
+        """
+        with ThreadPoolExecutor() as executor:
+            results = list(executor.map(self.check, mnemonics))
+        return results