bitcoin/test/functional/data

Various test vectors

mainnet_alt.json

For easier testing the difficulty is maximally increased in the first (and only) retarget period, by producing blocks approximately 2 minutes apart.

The alternate mainnet chain was generated as follows:

• use faketime to set node clock to 2 minutes after genesis block
• mine a block using a CPU miner such as https://github.com/pooler/cpuminer
• restart node with a faketime 2 minutes later

for i in {1..2016}
do
 t=$(( 1231006505 + $i * 120 ))
 faketime "`date -d @$t  +'%Y-%m-%d %H:%M:%S'`" \
 bitcoind -connect=0 -nocheckpoints -stopatheight=$i
done

The CPU miner is kept running as follows:

./minerd -u ... -p ... -o http://127.0.0.1:8332 --no-stratum \
        --coinbase-addr 1NQpH6Nf8QtR2HphLRcvuVqfhXBXsiWn8r \
        --algo sha256d --no-longpoll --scantime 3 --retry-pause 1

The payout address is derived from first BIP32 test vector master key:

pkh(xprv9s21ZrQH143K3QTDL4LXw2F7HEK3wJUD2nW2nRk4stbPy6cq3jPPqjiChkVvvNKmPGJxWUtg6LnF5kejMRNNU3TGtRBeJgk33yuGBxrMPHi/44h/0h/0h/<0;1>/*)#fkjtr0yn

It uses pkh() because tr() outputs at low heights are not spendable (unexpected-witness).

This makes each block deterministic except for its timestamp and nonce, which are stored in mainnet_alt.json and used to reconstruct the chain without having to redo the proof-of-work.

The timestamp was not kept constant because at difficulty 1 it's not sufficient to only grind the nonce. Grinding the extra_nonce or version field instead would have required additional (stratum) software. It would also make it more complicated to reconstruct the blocks in this test.

The getblocktemplate RPC code needs to be patched to ignore not being connected to any peers, and to ignore the IBD status check.

On macOS use faketime "@$t" instead.