Support aes256-gcm@openssh.com and aes128-gcm@openssh.com for key dec…#479
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kruton merged 2 commits intoconnectbot:mainfrom Mar 22, 2026
Merged
Support aes256-gcm@openssh.com and aes128-gcm@openssh.com for key dec…#479kruton merged 2 commits intoconnectbot:mainfrom
kruton merged 2 commits intoconnectbot:mainfrom
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…ryption OpenSSH keys encrypted with AES-GCM ciphers (e.g., via ssh-keygen -Z aes256-gcm@openssh.com) could not be imported, failing with "Cannot decrypt, unknown cipher". This adds GCM support to CommonDecoder using JCE's AES/GCM/NoPadding, and fixes OpenSSHKeyDecoder to read the AEAD authentication tag stored after the private section blob. Fixes connectbot/connectbot#1984 Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
kruton
requested changes
Mar 22, 2026
| // For AEAD ciphers (e.g., aes256-gcm@openssh.com), the authentication | ||
| // tag is stored after the private section blob in the key file. | ||
| // Read it and append to dataBytes so the cipher can verify it. | ||
| if (tr.remain() > 0) { |
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This changes the behavior of the program for non-AEAD ciphers. It should check the cipherName here to avoid problems.
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I beleieve that it is fixed by a new commit.
Guard the trailing-bytes read with an isAeadCipher() check so non-AEAD ciphers (CBC, CTR) are not affected. Add a regression test that appends garbage bytes to a non-AEAD key to verify they are ignored. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
kruton
approved these changes
Mar 22, 2026
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Fixes connectbot/connectbot#1984
Issue: Ed25519 keys encrypted with aes256-gcm@openssh.com couldn't be imported — the CommonDecoder didn't recognize GCM ciphers, throwing "Cannot decrypt, unknown cipher".
Root cause: Two problems:
Fix (3 files in sshlib, branch fix_ed25519aes256gcm based on main):