Debian on CD

Verifying authenticity of Debian CDs

Official releases of Debian CDs come with signed checksum files; look for them alongside the images in the iso-cd, jigdo-dvd, iso-hybrid etc. directories. These allow you to check that the images you download are correct. First of all, the checksum can be used to check that the CDs have not been corrupted during download. Secondly, the signatures on the checksum files allow you to confirm that the files are the ones officially released by the Debian CD / Debian Live team and have not been tampered with.

To validate the contents of a CD image, just be sure to use the appropriate checksum tool. For older archived CD releases, only MD5 checksums were generated in the MD5SUMS files; you should use the tool md5sum to work with these. For newer releases, newer and cryptographically stronger checksum algorithms (SHA1, SHA256 and SHA512) are used, and there are equivalent tools available to work with these.

To ensure that the checksums files themselves are correct, use GnuPG to verify them against the accompanying signature files (e.g. MD5SSUMS.sign). The keys used for these signatures are all in the Debian GPG keyring and the best way to check them is to use that keyring to validate via the web of trust. To make life easier for users, here are the fingerprints for the keys that have been used for releases in recent years:

pub   4096R/64E6EA7D 2009-10-03
      Key fingerprint = 1046 0DAD 7616 5AD8 1FBC  0CE9 9880 21A9 64E6 EA7D
uid                  Debian CD signing key <>

pub   4096R/6294BE9B 2011-01-05
      Key fingerprint = DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B
uid                  Debian CD signing key <>
sub   4096R/11CD9819 2011-01-05

pub   4096R/09EA8AC3 2014-04-15
      Key fingerprint = F41D 3034 2F35 4669 5F65  C669 4246 8F40 09EA 8AC3
uid                  Debian Testing CDs Automatic Signing Key <>
sub   4096R/6BD05CFB 2014-04-15