Hi all,

I was looking for a way to put data, like encryption keys, etc.
into a Face: Header, so that it can be used also for email.

For that task I used my identicons[1] program, with the string
'Stefan Claas', to generate the image with a size of 48x48 pixels
and from a friends recommendation:

$ optipng -o5 "identicon.png" -strip all -clobber -out i2.png

to shrink the file in byte size, to allow the insertion of exif
Header data. In my case my age[2] pub key.

To insert data I used:

https://dev.exiv2.org/projects/exiv2/wiki/The_Metadata_in_PNG_files

$ sudo apt install libimage-exiftool-perl

[1] https://github.com/stefanclaas/idendicons
[2] https://github.com/FiloSottile/age

Hope you find this little tip useful!

Regards
Stefan

Stefan Claas wrote:

> Hi all,
>
> I was looking for a way to put data, like encryption keys, etc.
> into a Face: Header, so that it can be used also for email.
>
> For that task I used my identicons[1] program, with the string
> 'Stefan Claas', to generate the image with a size of 48x48 pixels
> and from a friends recommendation:
>
> $ optipng -o5 "identicon.png" -strip all -clobber -out i2.png
>
> to shrink the file in byte size, to allow the insertion of exif
> Header data. In my case my age[2] pub key.
>
> To insert data I used:
>
> https://dev.exiv2.org/projects/exiv2/wiki/The_Metadata_in_PNG_files
>
> $ sudo apt install libimage-exiftool-perl
>
> [1] https://github.com/stefanclaas/idendicons
> [2] https://github.com/FiloSottile/age
>
> Hope you find this little tip useful!

Mmmhh, I am thinking now that it may be better to generate the identicon
with a string, like Name, email address, age pub-key and then include
the same info in the exif date.

Regards
Stefan

Stefan Claas wrote:

> Mmmhh, I am thinking now that it may be better to generate the
> identicon with a string, like Name, email address, age pub-key and
> then include the same info in the exif date.

Done. I put my Name, Email Address, age pub-key in both.

Enter your string:Stefan Claas, stefan@mailchuck.com,
age1m2e0uj8l4xej4kxv6n0yuhs76qljf0nlpwvcfz75w27dd20ma3hq2srpul Image
size, x = y:48

$ exiftool i2.png
ExifTool Version Number : 12.16
File Name : i2.png
Directory : .
File Size : 547 bytes
File Modification Date/Time : 2023:10:08 16:24:44+02:00
File Access Date/Time : 2023:10:08 16:24:45+02:00
File Inode Change Date/Time : 2023:10:08 16:24:44+02:00
File Permissions : rwxrwxrwx
File Type : PNG
File Type Extension : png
MIME Type : image/png
Image Width : 48
Image Height : 48
Bit Depth : 4
Color Type : Palette
Compression : Deflate/Inflate
Filter : Adaptive
Interlace : Noninterlaced
Palette : (Binary data 15 bytes, use -b option
to extract)
Transparency : 0 128 128
Description : Stefan Claas, stefan@mailchuck.com,
age1m2e0uj8l4xej4kxv6n0yuhs76qljf0nlpwvcfz75w27dd20ma3hq2srpul - age encrypted emails send to this address will be answered via the YAMN Remailer Network.
Image Size : 48x48
Megapixels : 0.002

Regards
Stefan

Stefan Claas <stefan@mailchuck.com> writes:

> I was looking for a way to put data, like encryption keys, etc.
> into a Face: Header, so that it can be used also for email.

Why into the Face image? I sometimes put some of my own (though not
encryption keys) in an X-... header.

> Hope you find this little tip useful!

Adding metadata to an image is simple enough, but you don't say what
problem you are trying to solve by doing it!

Do none of the standards for secure, authenticated or signed email not
meet your needs?

--
Ben.

Ben Bacarisse wrote:

> Stefan Claas <stefan@mailchuck.com> writes:
>
> > I was looking for a way to put data, like encryption keys, etc.
> > into a Face: Header, so that it can be used also for email.
>
> Why into the Face image? I sometimes put some of my own (though not
> encryption keys) in an X-... header.

I wanted to see what else can be done with a standard Face image, due
to its small size and out of curiosity.

> > Hope you find this little tip useful!
>
> Adding metadata to an image is simple enough, but you don't say what
> problem you are trying to solve by doing it!

Well, putting Metadata in an image allows people to omit a signature
at the bottom of a posting, or additional Headers. And it can be used
elsewhere.
> Do none of the standards for secure, authenticated or signed email not
> meet your needs?

For example, PGP or better said GnuPG are old and to complex, compared
to age, which I and friends use and a majority of others. Because an
age pub-key fits nicely in an image with additional information, such
an image can be used everywhere a user is present on the Internet. And
why have been identicons invented?

https://en.wikipedia.org/wiki/Identicon

Regards
Stefan

Stefan Claas <stefan@mailchuck.com> writes:

> Ben Bacarisse wrote:
>
>> Stefan Claas <stefan@mailchuck.com> writes:
>>
>> > I was looking for a way to put data, like encryption keys, etc.
>> > into a Face: Header, so that it can be used also for email.
>>
>> Why into the Face image? I sometimes put some of my own (though not
>> encryption keys) in an X-... header.
>
> I wanted to see what else can be done with a standard Face image, due
> to its small size and out of curiosity.

OK.

>> > Hope you find this little tip useful!
>>
>> Adding metadata to an image is simple enough, but you don't say what
>> problem you are trying to solve by doing it!
>
> Well, putting Metadata in an image allows people to omit a signature
> at the bottom of a posting, or additional Headers. And it can be used
> elsewhere.

I disagree, but that's not important since you are doing this among
(presumably) like-minded friends.

--
Ben.

Ben Bacarisse wrote:

> Stefan Claas <stefan@mailchuck.com> writes:

> >> Adding metadata to an image is simple enough, but you don't say
> >> what problem you are trying to solve by doing it!
> >
> > Well, putting Metadata in an image allows people to omit a signature
> > at the bottom of a posting, or additional Headers. And it can be
> > used elsewhere.
>
> I disagree, but that's not important since you are doing this among
> (presumably) like-minded friends.

Well, as little example. I had (I will create a new one soon) an age-ID
on GitHub, which was an .pdf, eIDAS certified and containing my pub key,
so that users could know this is *my* pub key. In that document I can
also place my Identicon, which additionally and visually shows a user
that this is the same key as in my email/news Identicon, without looking
at Headers, in case people are doing this.

Regards
Stefan