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My friend gave me a ubuntu live CD, for security reason I want to make sure the CD is safe to use.

I have checked the sha256sum and md5sum of the CD, but then I heard they have vulnerabilities too.

I know cmp compares two folders byte by byte. So can I use cmp /dev/cdrom ubuntu.iso to see if the CD is truly identical to the iso I downloaded from ubuntu.com? Is this even better than using sha256sum / md5sum?

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Have you tried reading the first line of man cmp? :-) –  Andrea Corbellini Sep 22 '13 at 22:28
Being paranoid is a good thing when it comes to technology, but to distrust a combination of sha256 and md5 is unnecessary. –  Joren Sep 22 '13 at 22:30
why not download a new one from official website, Ubuntu –  Shaharil Ahmad Sep 23 '13 at 4:55
The first line of man cmp? Isn't it compares two files byte by byte? But is a CD considered as a file? And I can't burn a disk myself. –  user195245 Sep 23 '13 at 19:26

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