[GH-ISSUE #17] Key exchange is slow/gets timeouts #15

New issue

Open

opened 2026-05-05 03:30:17 -06:00 by gitea-mirror · 1 comment

gitea-mirror commented

2026-05-05 03:30:17 -06:00

Owner

Originally created by @cy384 on GitHub (Aug 7, 2022).
Original GitHub issue: https://github.com/cy384/ssheven/issues/17

Key exchange is slow. This is arguably more of a bug in mbedtls but I want to track it here for my purposes. Notes:

diffie-hellman-group1-sha1 key exchange method is too slow to run on (some? all?) 68k machines
implementations in bignum.c in mbedtls, revisit mbedtls_mpi_exp_mod specifically
figure how to detect when the remote host drops us due to timeout and tell the user
figure out and document the minimum specs for the various methods
is there some keepalive flag or message, either OT/TCP or in ssh/libssh2 that we can be using to prevent timeouts?

Originally created by @cy384 on GitHub (Aug 7, 2022). Original GitHub issue: https://github.com/cy384/ssheven/issues/17 Key exchange is slow. This is arguably more of a bug in mbedtls but I want to track it here for my purposes. Notes: * diffie-hellman-group1-sha1 key exchange method is too slow to run on (some? all?) 68k machines * implementations in bignum.c in mbedtls, revisit mbedtls_mpi_exp_mod specifically * figure how to detect when the remote host drops us due to timeout and tell the user * figure out and document the minimum specs for the various methods * is there some keepalive flag or message, either OT/TCP or in ssh/libssh2 that we can be using to prevent timeouts?

gitea-mirror added the

bug

label 2026-05-05 03:30:17 -06:00

gitea-mirror commented

2026-05-05 03:30:22 -06:00

Author

Owner

@reukiodo commented on GitHub (May 12, 2023):

Is there debug output to see what cipher/key exchange the client is using to connect?

@reukiodo commented on GitHub (May 12, 2023): Is there debug output to see what cipher/key exchange the client is using to connect?