Getting ubuntu iso securely

[J Fernyhough]

It's no more secure than running:

sha256sum -c ubuntu-installer.iso.shasum

or just:

sha256sum ubuntu-installer.iso

and manually checking the values match.

I'd even argue a script is less secure, as the user is running an arbitrary
script they've downloaded. It's also no more straightforward as the user
has to download and run the script. Whatever format the script is, the user
still has to set it as executable. By this point, reading a line of
instruction and running a single command is pretty trivial.

I understand what you're trying to do, I just think you're trying to solve
a problem that doesn't exist.


On 15 September 2015 at 20:40, Ryein Goddard <ryein.goddard at gmail.com>
wrote:

> We are talking about a more secure method with a built in way to checksum
> that is easy for users not the Pentagon.
>
> On Tue, Sep 15, 2015 at 12:30 PM, J Fernyhough <j.fernyhough at gmail.com>
> wrote:
>
>> An "open" script with an encrypted checksum? What's to stop someone
>> compromising this script during transport? You have recreated *exactly* the
>> same problem, just a level higher.
>>
>> On 15 September 2015 at 20:27, Ryein Goddard <ryein.goddard at gmail.com>
>> wrote:
>>
>>> That part is easy because it could be a open script with probably less
>>> then 10 lines of code.
>>>
>>> On Tue, Sep 15, 2015 at 12:23 PM, J Fernyhough <j.fernyhough at gmail.com>
>>> wrote:
>>>
>>>> And how would you know the Ubuntu-branded downloader is secure?
>>>>
>>>> I think you're over-complicating things here. Anyone interested in
>>>> verifying a download is correct can verify the posted SHAsum, and anyone
>>>> really concerned could install from a netboot (mini.iso), check its seed
>>>> file, and download all packages from a known repo.
>>>>
>>>> If you are concerned about an installer download becoming compromised
>>>> during transport then you should also be concerned about the apt transport
>>>> used - I'm assuming you set your deb sources to https? If not, then a
>>>> 'secure' installer image is moot.
>>>>
>>>> J
>>>>
>>>>
>>>>
>>>> On 15 September 2015 at 20:10, Ryein Goddard <ryein.goddard at gmail.com>
>>>> wrote:
>>>>
>>>>> You could add multiple sources that store an encrypted checksum and
>>>>> then reference that with an Ubuntu branded downloader.  That program would
>>>>> be pretty easy to make and it would abstract away all requirements for
>>>>> anything time consuming from the user.
>>>>>
>>>>> On Tue, Sep 15, 2015 at 3:53 AM, Ralf Mardorf <
>>>>> ralf.mardorf at alice-dsl.net> wrote:
>>>>>
>>>>>> On Mon, 14 Sep 2015 15:07:02 -0700, Ryein Goddard wrote:
>>>>>> >On Mon, Sep 14, 2015 at 10:32 AM, Ralf Mardorf wrote:
>>>>>> >> On Mon, 14 Sep 2015 16:19:36 +0000 (UTC), rajeev bhatta wrote:
>>>>>> >> >It is not time consuming.. just for the user experience..
>>>>>> >>
>>>>>> >> IMHO for averaged users it is time consuming. Even a power users
>>>>>> not
>>>>>> >> necessarily deals with the right people to get a key she or he can
>>>>>> >> trust, that can be used to verify ownership of the particular
>>>>>> >> public Ubuntu key.
>>>>>> >>
>>>>>> >> I am a Linux power user and I don't own a key to verify the
>>>>>> >> particular public key, that belongs to the key, that was used to
>>>>>> >> sign the Ubuntu images.
>>>>>> >>
>>>>>> >> Please let me know, how I can get such a key, without spending much
>>>>>> >> time ;).
>>>>>> >
>>>>>> >If a current method doesn't exist then maybe we can just create one?
>>>>>>
>>>>>> How will you make it less time consuming?
>>>>>>
>>>>>> You need to meet other people in the real world, in addition you
>>>>>> need to know and trust those people and in addition they need to
>>>>>> trust a
>>>>>> chain of trusted keys, that confirms ownership of the public Ubuntu
>>>>>> key
>>>>>> in question. https://en.wikipedia.org/wiki/Web_of_trust
>>>>>>
>>>>>> This already is hard to realise for hardcore computer geeks and
>>>>>> completely illusorily for those who's centre of life isn't the
>>>>>> operating system of their computers or digital security.
>>>>>>
>>>>>>
>
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