Add PGP support during transfer

[debilin]

Please allow to encrypt/decrypt using PGP during transfer from host1 to host2. So for example, I need to pull from host1, decrypt the email using my PGP key and then upload to host2. The emails on host2 are unencrypted.

[gilleslamiral]

Do you know a command decrypt to do it on the command line, with an rfc822 email as input, like this;

cat email_encrypted.txt | decrypt > email_decrypted.txt

[debilin]

@gilleslamiral Let me try it and see. But can we run this in between imapsync transfer process? I need this to be automated along with imapsync.

[gilleslamiral]

Let me try it and see.

First, you have to find it. decrypt is a name I just made up.

Can we run this in between imapsync transfer process?

Yes, with the --pipemess option. Here are two dummy examples:

imapsync ... --pipemess cat 

imapsync ... --pipemess '(cat|cat)'

All email messages transferred by imapsync will go through these commands cat or cat | cat

https://imapsync.lamiral.info/README
...

     --pipemess     cmd  : Apply this cmd command to each message content
                           before the copy.
     --pipemess     cmd  : and this one, etc.
                           With several --pipemess, the output of each cmd
                           command (STDOUT) is given to the input (STDIN)
                           of the next command.
                           For example,
                           --pipemess cmd1 --pipemess cmd2 --pipemess cmd3
                           is like a Unix pipe:
                           "cat message | cmd1 | cmd2 | cmd3"

[debilin]

First, you have to find it. decrypt is a name I just made up.

I see 🤦‍♂️ I thought it's an existing program on my system. I will look around and report back

[gilleslamiral]

I searched and found nothing doing the job completely.
The command gpg can decipher the email from STDIN to STDOUT, which is excellent for --pipemess, but only the encrypted part, the other parts are thrown away.

You're bound to write the tool if you really need it.

[debilin]

That's what I found as well. gpg --decrypt almost works nicely. Thanks for your help. I will search around more to see if there is anything I can do beside coding it myself.

[gilleslamiral]

https://imapsync.lamiral.info/TODO
...

SUGGESTED 2023_10_14 by debilin
https://github.com/imapsync/imapsync/issues/416
Add PGP support during transfer
Write a tool to keep STDIN as is like the cat command except for the pgp parts
where gpg is invoked to do its job.

gilles@petite:~ 73$ cat toto.txt | LANG= gpg --decrypt  --batch --no-tty  --passphrase=$P  --allow-multiple-messages  2>/dev/null 
toto

gilles@petite:~ 74$ cat toto.txt
From: gilles@lflflf
Subject: rrrrr


-----BEGIN PGP MESSAGE-----
Version: GnuPG v1

hQEOA+8dQNKixMtCEAP/Qr4TlMPXn72GOKQoPS4Hke3Bt8i5/Vp05u2sJrJopfV1
MorlhUeMbpZwBEsT+FzQYe0QrBdeH9bg43pjS5UJ83PK970By0hUQWXWprRRcmYC
XE3DtDXzaWsUguB79PGWNDP+OaUH2PaaapLUw6X3aePkFIk+CjNFBR961yAchUED
/2hSA6exyLuzWq9BUvU7Iqvei3l+6wZAnWnFbUNloqOR6H92lPTFVhSQj/TK3uxa
WMlb19SMvXuSMWxaIhCmTKD9uXV3sXptshMSkne7OGTu/RWdwEQhQCQdmMBnBz0e
9btnB/3brQXchfvsjL6XCowUBzB+w3mdcXeM3Hps7KJ/0kABl8L3KDw0tS92KpGo
dtiykQebYl/et8gfqemxzOwvakaAzattU75BAPwcNJo2jU9fMdjDxgGntUweJOpT
z0rF
=bya7
-----END PGP MESSAGE-----