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Author Topic: Encryption for use on an iBook  (Read 8671 times)

Bill St. Clair

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Encryption for use on an iBook
« Reply #30 on: July 07, 2005, 06:34:56 am »

It's good that you're learning the command line tools, but as I said in my message, you don't really need to. Wait for a few megabytes of download, and you'll have GUI tools that do it for you.

First, get GPG  Keychain, to make managing keys easier. You've got to import your friends' keys into your keyring before you can encrypt mail for them.

Second, get GPGMail, which will do encryption automatically from Apple's mail program. If you're using a different mail program, this won't help you. In that case, look for a GPG plug-in for that mail program or get GPGDropThing to enable encrypting text using the clipboard instead of via files.
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"The state can only survive as long as a majority is programmed to believe that theft isn't wrong if it's called taxation or asset forfeiture or eminent domain, that assault and kidnapping isn't wrong if it's called arrest, that mass murder isn't wrong if it's called war." -- Bill St. Clair

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Junker

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Encryption for use on an iBook
« Reply #31 on: July 07, 2005, 09:59:52 am »

Thanks to Bill. I'm glad we got someone with a Mac on board. And someone who's of the hacker nature.
- - -

As a preface, I recommend to Kirsten:

http://www.gnupg.org/(en)/documentation/guides.html
---
The GNU Privacy Handbook

Thanks to the DocBook system, John Michael Ashley 's The GNU Privacy Handbook (GPH for short) is available in several formats:

as on-line browsable HTML file
as Adobe's PDF
[edit out the others]
---

It explains it all. My copy of the PDF is 200KB. Not too large for dial-up downloading.
- - -


So, up to now we've got two options:
1. The GPG already running as a text program in the terminal window, and
2. A possible future download of GUI programs.

Easiest to use is 2 and prolly oughta be done, but since I started Kirsten with 1, the TUI, I'll continue there until she chooses otherwise.
- - -


There we've got two continuing issues:
1. Making a new key pair with a different name, but same email address, and
2. The process of encrypting text for use in emails.


So, 1:

Short: Go ahead and make a second key-pair. Using the same email-addr won't kill anything. Note: ID the key by the part that is different.


Long: You can also make subordinate userIDs, useful for having a private ID and a public ID with both using the same key-pair. See the Handbook for how and why.
- -

And 2:

Short: Your "encrypt and attach the file to your email" will work fine.


Long: I encrypt my text files into the "ascii armored output" using the command-line option "--armor".

Getting:

-----BEGIN PGP MESSAGE-----
Version: GnuPG v1.2.2 (GNU/Linux)

hQQOA6k+mjEw3rj4EA/+Kx85JzAJRj33qG1Y9mmZMkA0VrhlFYu+f65HU1osX5lq
[etc.]
-----END PGP MESSAGE-----

That way, I can open the file into a text processor and copy/paste the text into an email. Some email reader programs can decrypt the "ascii armored" text right there in the email reader. That makes it more convenient for the recipient.

See Handbook. "--armor" can be used on any command that generates non-text output.
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securitysix

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Encryption for use on an iBook
« Reply #32 on: July 07, 2005, 11:24:00 am »

If you want to send someone an encrypted email, you will need their public key.  Basically, you encrypt the message and/or file with their public key and send it to them.  They then decrypt the message with their private key (I'm oversimplifying, but hopefully it gets the idea across), and can read it.

If you want to test to see if your key works to both encrypt and decrypt, you can send a message do yourself encrypted with your public key and see if you can decrypt it.  The easy part of this is sending yourself an email since all you have to do is put your own email address in the "To:" line.  The howto of encrypting and decripting will have to be left to those with more experience in Mac OS.
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Kirsten

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Encryption for use on an iBook
« Reply #33 on: July 09, 2005, 07:28:12 pm »

*
« Last Edit: February 23, 2007, 07:25:43 am by Kirsten »
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Bill St. Clair

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Encryption for use on an iBook
« Reply #34 on: July 09, 2005, 07:49:20 pm »

PGP (Pretty Good Privacy) and GNU Privacy Guard implement a Public Key Cryptosystem. They use an asymmetric cipher that has two keys, a public key, used for encryption, and a private key, used for decryption. You can safely give away the public keys, because computing the private key that goes with a public key is very computationally expensive. It can be done, but it takes a very long time on a very fast machine.

It's actually a little more complicated than that. The actual encrypting of your message is done with a symmetric cipher, an encryption algorithm that uses the same key for encrypting and decrypting. This "message key" is randomly generated for each message. The public key system is used to encrypt the message key. The encrypted forms (one for each person that you want to be able to decrypt the message) of the message key are sent along with the message encrypted with that key.

It's done that way because the public key encryption algorithm is slow, but the symmetric cipher algorithm is fast. Also, the message key is a fixed, fairly short, length. Multiple encrypted copies of the message key, one for each recipient, are smaller than multiple encrypted copies of the potentially very long message.

Besides the public keys in that thread, many of us have put our public keys on our profile page, the page you get to when you click on our name .
« Last Edit: July 09, 2005, 07:57:40 pm by Bill St. Clair »
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"The state can only survive as long as a majority is programmed to believe that theft isn't wrong if it's called taxation or asset forfeiture or eminent domain, that assault and kidnapping isn't wrong if it's called arrest, that mass murder isn't wrong if it's called war." -- Bill St. Clair

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Kirsten

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Encryption for use on an iBook
« Reply #35 on: July 09, 2005, 08:40:13 pm »

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« Last Edit: February 23, 2007, 07:23:30 am by Kirsten »
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Kirsten

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Encryption for use on an iBook
« Reply #36 on: July 10, 2005, 01:59:29 pm »

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« Last Edit: February 23, 2007, 11:43:09 am by Kirsten »
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Bill St. Clair

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Encryption for use on an iBook
« Reply #37 on: July 10, 2005, 02:09:10 pm »

Yay!
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"The state can only survive as long as a majority is programmed to believe that theft isn't wrong if it's called taxation or asset forfeiture or eminent domain, that assault and kidnapping isn't wrong if it's called arrest, that mass murder isn't wrong if it's called war." -- Bill St. Clair

"Separation of Earth and state!" -- Bill St. Clair

Junker

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Encryption for use on an iBook
« Reply #38 on: July 10, 2005, 08:07:24 pm »

Yes!!

Good work, Kristen.

If you want the public keys from the thread, I suggest:
1. Download the print version of the whole thread (link at bottom of any page of its posts).
2. Copy *the displayed version* of the html file into a new text file.
3. Save it as a text file to an appropriate directory, say as "thekeys.txt".
4. Do: pgp --import thekeys.txt > thekeys.toc

That will load all the keys from thekeys.txt into your key ring, and the "> thekeys.toc" part will put the list of key owners (user IDs) into the file "thekeys.toc" where you can see them all in your text editor.
« Last Edit: July 10, 2005, 08:18:46 pm by Junker »
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Kirsten

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Encryption for use on an iBook
« Reply #39 on: July 10, 2005, 10:45:28 pm »

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« Last Edit: February 23, 2007, 07:24:12 am by Kirsten »
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Junker

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Encryption for use on an iBook
« Reply #40 on: July 10, 2005, 11:41:59 pm »

type> gpg --armor --export yourIDname > mykey.txt

mykey.txt will contain something like:

-----BEGIN PGP PUBLIC KEY BLOCK-----
Version: GnuPG v1.2.2 (GNU/Linux)

mQGiBEKS8FwRBACdzzfBdbtskzBuqM/3eQtgc2KX0N1JZkJ4kML4x7MICT0l9YpS
[...]
RgQYEQIABgUCQpLxVgAKCRDtf9iRQ5vx8joAAJ487PrFegA/e8OiGmlfFSqJ9/A3
/wCfSV/9QA2utj/usM5xMLNTmZYm+FI=
=kAko
-----END PGP PUBLIC KEY BLOCK-----

Then copy & paste it into the post edit box.
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Bill St. Clair

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Encryption for use on an iBook
« Reply #41 on: July 11, 2005, 06:31:16 am »

Or check the "ASCII armored" checkbox in the "GPG Keychain Access" export dialog.
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"The state can only survive as long as a majority is programmed to believe that theft isn't wrong if it's called taxation or asset forfeiture or eminent domain, that assault and kidnapping isn't wrong if it's called arrest, that mass murder isn't wrong if it's called war." -- Bill St. Clair

"Separation of Earth and state!" -- Bill St. Clair

Kirsten

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Encryption for use on an iBook
« Reply #42 on: July 12, 2005, 12:03:11 am »

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« Last Edit: February 23, 2007, 07:24:36 am by Kirsten »
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Bill St. Clair

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Encryption for use on an iBook
« Reply #43 on: July 12, 2005, 06:48:13 am »

Near the top of the GPGMail page is a box containing instructions for re-enabling the GPGMail bundle in Mac OSX 10.4. Hopefully, following those instructions will fix your problem. $HOME is your home directory. If you double click on your disk icon on the Finder desktop, there will be a house icon labelled with your account name below the "Desktop" icon in the left-hand column. Click on that, then navigate to "Library", and "Mail", and you should see a "Bundles (Disabled)" item which you can rename to "Bundles". Then copy and paste the command line commands (The "Terminal" application is in Applications / Utilities).

You posted two different public keys, a 1024-bit key named "Kirsten..." and a 4096-bit key named "Freida McDoodle". I encrypted to the former. I just sent another message encrypted to the latter. Fix the GPGMail bundle first. Then you should be able to decrypt either message by clicking a button.

Note that GPGMail does the right thing. It shows you the decrypted message in the normal place, but does NOT save the plaintext on your disk. The next time you visit this message, you will again see the encrypted form and need to enter your passphrase to decrypt.
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"The state can only survive as long as a majority is programmed to believe that theft isn't wrong if it's called taxation or asset forfeiture or eminent domain, that assault and kidnapping isn't wrong if it's called arrest, that mass murder isn't wrong if it's called war." -- Bill St. Clair

"Separation of Earth and state!" -- Bill St. Clair

Kirsten

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Encryption for use on an iBook
« Reply #44 on: July 12, 2005, 09:59:25 am »

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« Last Edit: February 23, 2007, 07:24:59 am by Kirsten »
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