Built a couple tools to download historical Certificate Transparency logs into the Static CT format, and compress them into self-verifying zip files, each coving a subtree of height 24.

This will let us store these datasets at @internetarchive for future research.

Example archive: https://archive.org/details/ct_digicert_yeti2018
Mailing list discussion: https://groups.google.com/a/chromium.org/g/ct-policy/c/Y25hCTrCjDo/m/yrjDnX7IAQAJ