After update Bitcoin Core to version 0.15, chainstate database changed format of data.

Old prefix of key has been 0x63, now 0x43, and key/value are different

Where is the new format described, or can someone have work on this?







Prefix BYTE:





0x00 -> 0x00(0)


0xD42A -> 0x2AAA(10922)

Block Height:

Code >> 1 = 0x1555(5461)

Is Coinbase:

Code & 1 = 0x00(0)


0xDE0D -> 0x2F8D(12173) -> decompressMSB128 -> 0x21084(135300)


0xFD6A -> 0x3F6A(16234)

1 Answer 1


Each entry in the new 0.15 format is defined as outpoint:coin, and has the following structure:

Outpoint is formed by: key | tx_hash | index.

Where the key corresponds to b'C', or 43 in hex. The transaction hash in encoded in Little endian, and the index is a base128 varint. The corresponding Bitcoin Core source code can be found here.

On the other hand, a coin is formed by: code | value | out_type | script.

Where code encodes the block height and whether the transaction is coinbase or not, as 2*height + coinbase, the value is a txout compressed base128 varint, the out_type is also a base128 varint, and the script is the remaining data. The corresponding Bitcoin Core source code can be found here.

Version 0.15 still used an obfuscation key to avoid triggering anti-virus software, you can check this answer to know how it is stored in the database and how to use it to de-obfuscate you data.

Finally, if you need a decoder for both versions 0.14 (0.8-0.14) and the new 0.15 format, you can check this GitHub repo (particularly functions decode_utxo and decode_utxo_v08_v014 from utils.py).

Disclaimer: I'm the author of the repo.

  • I parsed Key, But with Value i have a problem. Question updated
    – Ninazu
    Nov 4, 2017 at 10:51
  • What's the problem?
    – sr_gi
    Nov 4, 2017 at 15:25
  • There can be still something? Data does not converge. In question i try parse example from db. I get txhash and index from outpoint. blockchain.info/tx/…. But any other fields in coin invalid. The simplest field is the script, since it remains unchanged. I cant find any part of script in transaction
    – Ninazu
    Nov 4, 2017 at 15:53
  • For what I see, the coin and the outpoint you are giving as example do not match. The corresponding coin for '43000000dcf3713a29f3da53dbde07ea93ace52a4393ba9a009d8ac17c853c18e500' is 'bafe78849575007b8268c6115b707d17cccfdf9be636467a80f9e4'. Either way, the data you have decoded in your updated question match with the coin you provided, but since the coin seems not to be correct, the parsing goes wrong at the end.
    – sr_gi
    Nov 4, 2017 at 15:54
  • 1
    The chainstate use to trigger some anti-virus software in windows systems, by XORing the information the signature of the data changes and there is no more false positive with AV.
    – sr_gi
    Nov 5, 2017 at 14:33

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