There is another issue about the performance of Kleopatra when encrypting large archive files

I edited this task a bit: For compression we have T6332
For Archives passed to Gpgtar we have: T6342

I would like this issue to be for the case https://lists.gnupg.org/pipermail/gnupg-users/2023-January/066397.html that:

Encryption:
Size | GnuPG | Gpg4win
1GB | 38 sec. | 1 min. 8 sec.
1GB | 37 sec. | 1 min. 7 sec.
2GB | 1 min. 14 sec. | 2 min. 15 sec.
2GB | 1 min. 14 sec. | 2 min. 14 sec.
5GB | 3 min. 10 sec. | 6 min. 10 sec.
5GB | 3 min. 6 sec. | 5 min. 34 sec.
10GB | 6 min. 28 sec. | 11 min. 21 sec.
10GB | 6 min. 21 sec. | 11 min. 6 sec.

Results of decryption:

Size | GnuPG | Gpg4win
1GB | 3 sec. | 36 sec.
1GB | 3 sec. | 34 sec.
2GB | 10 sec. | 1 min. 13 sec.
2GB | 7 sec. | 1 min. 12 sec.
5GB | 22 sec. | 3 min. 1 sec.
5GB | 19 sec. | 3 min. 2 sec.
10GB | 1 min. 3 sec. | 5 min. 52 sec.
10GB | 1 min. 7 sec. | 6 min. 5 sec.

Which would be solved in my opinion if we would have the filenames for encryption and decryption passed directly to GnuPG and not go through the GPGME callback layers. This is very similar to what T6342 is about. But different enough that it warrants its own issue.

Tested encryption (+ signature) via Kleopatra with a 3 GB file (random data) with:

• VSD 3.2.4: ~ 5:20
• VSD 3.3.0: ~ 4:25
• command line; ~4:25

So there was a speedup for this case an it's now as fast via Kleopatra as via the cli. Mission accomplished ;-)

To make the test complete for VSD, here the times for decryption (and verification) of the 3G file from above:

• VSD 3.2.4: ~3:36
• VSD 3.3.0: ~2:20
• command line: ~2:30 (maybe the bit slower than in Kleo is because this was done in a shared folder of the host system instead of on the c: partition)

The cli was done in both tests with the gpg version from VSD 3.3.0

For Gpg4win 4.4.0:
Encryption: ~2:35
Decryption: ~0:44

cli, encryption: ~2:10
cli, decryption: ~ 0:44

For comparison Gpg4win 4.3.1:
Encryption: ~3:30
Decryption: ~2:10

-> definitiv an improvement for encryption + decryption but the encryption has not become as fast as on the command line.

Again for Gpg4win 4.4.0, this time with better attention (and definitively encryption only):

Encryption only in Kleo, same 3GB random data file: ~ 2:23, 2:22, 2:25
(for Ted, same as below)

Encryption cli 4.4.0:
gpg -e -r ted -3G.txt
~ 2:15, 2:14, 2:15

I'd say that's close enough.