BIP328: Use Base58Check in ExtendedKey.deserialize and validate length #1955

1. 
   sashass1315 commented at 9:09 am on September 5, 2025: contributor

   • Replace raw Base58 decode and manual slice with base58.decode_check(xpub) to enforce checksum validation as required by BIP-32 and as implied by the method docstring.
   • Add strict len(data) == 78 check before parsing to ensure the serialized extended key length matches the BIP-32 78-byte structure.
   • This prevents accepting corrupted or truncated extended keys and aligns deserialization behavior with Base58Check semantics.
2. Use Base58Check in ExtendedKey.deserialize and validate length fd9f5694a8
3. in bip-0328/_xpub.py:137 in fd9f5694a8 outdated

   132@@ -133,7 +133,9 @@ def deserialize(cls, xpub: str) -> 'ExtendedKey':
   133 
   134         :param xpub: The Base58 check encoded xpub
   135         """
   136-        data = base58.decode(xpub)[:-4] # Decoded xpub without checksum
   137+        data = base58.decode_check(xpub)
   138+        if len(data) != 78:
   

   ---

   ---

   

   jonatack commented at 4:24 pm on September 5, 2025:

   Maybe describe the origin of the 78 value.

   0        if len(data) != 78:  # BIP32 Serialization Format defines a 78-byte structure.
   

4. 
   jonatack commented at 4:26 pm on September 5, 2025: member

   Pinging BIP author @achow101 for feedback.
5. jonatack added the label Pending acceptance on Sep 5, 2025
6. Update bip-0328/_xpub.py

   Co-authored-by: Jon Atack <jon@atack.com>

   fc10bd4995
7. murchandamus requested review from achow101 on Feb 28, 2026
8. 
   murchandamus commented at 0:18 am on February 28, 2026: member

   @achow101: Strikes me as AI;DR, but please let me know if you want this one.
9. 
   achow101 commented at 0:31 am on February 28, 2026: member

   NACK, pointless code churn
10. 
    murchandamus commented at 1:18 am on February 28, 2026: member

    Closing as it was declined by the BIP owner.
11. murchandamus closed this on Feb 28, 2026

    ---

12. murchandamus removed the label Pending acceptance on Feb 28, 2026
13. murchandamus added the label Proposed BIP modification on Feb 28, 2026

Contributors
sashass1315 jonatack murchandamus achow101

Review Requested
achow101

Labels
Proposed BIP modification