Hash Sums

Ali Snedden
  • 1
  • 22 Oct '22

Hello,

I was trying to download the data using the command :

wget -nd -nc -nv -e robots=off -l 1 -r -A hdf5 --content-disposition --header="API-Key: MYTOKEN " "http://www.tng-project.org/api/Illustris-3/files/snapshot-135/?format=api"

After downloading the data, I downloaded the check / hash sums from https://www.tng-project.org/api/Illustris-3/checksums/snapshot-135/ . It doesn't say which algorithm is used, but I think it is sha256sum. I've downloaded it twice, and I get the same checksum each time, but they disagree with the above's checksum.

My sha256sums :
53ca2a31e33116cd48044a63fb1c9090d120b2bf6a7d6a967291a2745d3a8a35 snap_135.0.hdf5
0cf55281b036542a435b1332aa6e7a0c4a1b7e06b67c1ebabb7e7659eeaafab4 snap_135.10.hdf5
e057a08dc58463bdf773310825cf111ed4c9326130184e7d5b99c46276d0a985 snap_135.11.hdf5
d11975e77011734666b0765780fe7f5185b239ee12db1758f541bd41bac3753a snap_135.12.hdf5
18033f9d475c0bd23c414613aa4de66f3119a4466d11c60b4d8a0b68233ae590 snap_135.13.hdf5
72837d93703a5746ad0aa6cd1232df31bdd6a68eaeb4e303c9e24bc41bc84baa snap_135.14.hdf5
b448d5bd6faf225f098409f0f7c497d52c35dc17f3a78fd82ed4fdd21c623dbc snap_135.15.hdf5
1a571a3669bc8a6db581c3fa7659d76f92bf0615809323a7c6ae631d5368b21b snap_135.16.hdf5
cd08129f4f85ab882206c79650ee6ea0eb5b749089ebc039dd0e3989fcb161ed snap_135.17.hdf5
5dcee3ba43b91b116d3f9c851a0211ae2fa0d91ccb35cbc8a9bad31fd0ba3aa9 snap_135.18.hdf5
f0a5f4a126d391758278f2f18e7edd37aac3993f09cf3ee75dff63bafb1b2e51 snap_135.19.hdf5
668da0fae07f5e88455920e906a385ada98365fcc9fdb2ac02a3eac3ea51e95d snap_135.1.hdf5
b233b6724eebfbdf106c6f43d922c72665f486805722ae0b028e67c9785e8b01 snap_135.20.hdf5
e6d28e75755592f824e4e5ddfb54240bc84c8f16f78ea1581a36d0edd38eecce snap_135.21.hdf5
d163f4a23dc48f1387a505a79736d8ba14cda65063b46cc5694232b816af2011 snap_135.22.hdf5
84b200d02a61bccca37bd31c1b8803cbac1b7f8fe7b0600790b6fa9457b473ca snap_135.23.hdf5
2d38ecb5c5103a67d1232c88065a485070d9d1c9175f782ecfab2f80a8b3fdba snap_135.24.hdf5
51ea9c1ba929e6ee967cb38e221cc89583a749064c83bc461eabae6d1e7842b8 snap_135.25.hdf5
c4155961dc57f6363a2e797fd75742335de8bcc337e06ea7191aa8ebebc48b58 snap_135.26.hdf5
aa033bd04f298056dacbe57dcd81293a7e16681567ffe047965d9e3249660e04 snap_135.27.hdf5
c815f565dd76be63244bbdfe37f0abbaaf8e4c35d4a84c90b111106607255921 snap_135.28.hdf5
e2ce87340741addda20b8a31532a2a02f294dc7792bfbc681bda4efa75e56a42 snap_135.29.hdf5
f48abf254e355c815464d02969fe78b9f4af4f5295f3cf78158d9c219f4386f0 snap_135.2.hdf5
c33281847854c788562507be90fa415fd96912fc547156477e9da3a1091a5e36 snap_135.30.hdf5
95f282c90d2bd8c6ed112054652b47d70be7f55a6b816edebe591ddb8f301afd snap_135.31.hdf5
3f610584a94d1e4b00745f03961bd752b79dc8891f2dc3c8ea5929a528c027a0 snap_135.3.hdf5
fc6b80a41beff7c8533c9cc59aafaf0af931e0328e9234197a876296b773e32a snap_135.4.hdf5
6bebc48202514ff70764047e2ebb29bc29fafacb90bcb0e4b4f6d7de93f43a04 snap_135.5.hdf5
58e6decef1fa7df1c10e5e2d9d8b192cec554ef4a076e4edc3e24314ba37d299 snap_135.6.hdf5
5d24eed75c6a972f1e7090927d424fcfe6b81dca64eff11c16d98011e87430cf snap_135.7.hdf5
c6297965f44d34d577e6cd9021348931cc315082ad882c586fc3f35ae59ba78c snap_135.8.hdf5
854fb2ea284d79e4e4c0dcbbde48d43b6124d8fdd3538657ca1773c28f15103b snap_135.9.hdf5

Question :

  1. Which algorithm and options were used for the checksums? I'm trying to figure out why mine disagree with the ones available from TNG

Thanks,
Ali

Dylan Nelson
  • 28 Oct '22

Hello,

You are correct, this is sha256sum (this is described in the data release paper of the original Illustris simulation, Nelson+2015).

Your checksums are also correct. The issue is that we changed the original Illustris files, when TNG was released. In particular, we added the "StellarHsml" field. Unfortunately, I never updated the checksums, because I didn't see that people were actually using these. (Most download methods will automatically verify the integrity while downloading, nowadays).

It's on my todo list for the future to update the checksums (for the original Illustris runs).

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