Is a 256-bit hash which is all zeroes a valid trie root? about pyethereum HOT 2 CLOSED

The root of the empty trie is a 0_256 (i.e. a 32-byte 'hash' of zeros).
From the YP:

The empty trie is defined as being a 256-bit hash of zeroes, $0_{256}$.

Trie roots are allowed to be deep (and there are several real examples of
this), but the empty trie has, since
ethereum/aleth@4aa0c71
been
defined as the zeroed hash.

This means all nodes are either 2 or 17 items; never zero.

Never put down to incompetence that which can be adequately explained by
self-interest.

On 13 May 2014 14:04, heikoheiko [email protected] wrote:

currently we don't get compatibility with the cpp client. the state.roots
after adding the premine accounts differ. I tried to isolate the problem:
https://github.com/ethereum/pyethereum/blob/master/tests/test_chain.py#L88

from the YP it looks like empty trie roots would be represented as
'\x00'*32 in the cpp client. if so it would not match the empty string
that we use.

• Comment by Vitalik Buterin: that's wrong, trie roots are allowed to
  be either empty or even deep arrays (though that should never happen in
  practice)

YP: https://raw.githubusercontent.com/ethereum/latexpaper/master/Paper.tex
0256 , SHA3RLP(), 0160 , stateRoot, 0256 , 2**22 , 0, 0, 1000000, 0, 0,
(), SHA3(42), (), ()

Where 0256 refers to the parent and state and transaction root hashes, a
256-bit hash which is all zeroes; and the implementation looks like it
would implement it just like this:
https://github.com/ethereum/cpp-ethereum/libethereum/BlockInfo.cpp#L64

h256() << sha3EmptyList << h160() << stateRoot << h256() <<
c_genesisDifficulty << 0 << 0 << 1000000 << 0 << (uint)0 << string() <<
sha3(bytes(1, 42));

also the default for an account looks different in cpp
['', '', h256(), sha3('')] rather than ['', '', '', ''] currently in
pyethereum.

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Reply to this email directly or view it on GitHubhttps://github.com//issues/91
.

from pyethereum.

thanks. see #92

from pyethereum.