SFTP: PKCS#8 OpenSSL key format not supported

[stephanritscher]

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Describe the bug / provide steps to reproduce it

When creating a PKCS#8 key using openssl genpkey tool, the generated key cannot be imported by Acode for SFTP drives.

E.g. create unencrypted RSA key with
openssl genpkey -algorithm RSA -out key.pem
Create SFTP drive with public key authentication, select key.pem, no password and press save.
Error toast: Invalid passphrase for key file

Those are key files starting with
-----BEGIN PRIVATE KEY-----

The same holds for encrypted key files generated by genpkey which start with
-----BEGIN ENCRYPTED PRIVATE KEY-----
and also for EC keys which can also be generated by genpkey and be hold by this key format.

Opposed to that, PKCS#1 keys generated by openssl rsa -traditional can be imported:
openssl genrsa -traditional -out rsa.key
These start with
-----BEGIN RSA PRIVATE KEY-----
The same holds for EC keys in PKCS#1 format which start with
-----BEGIN EC PRIVATE KEY-----
and the encrypted variants.

Environment

Acode 1.11.7
Android 16

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If applicable, attach your Acode.log file to this issue.

Acode.log

[stephanritscher]

I used OpenSSL 3.6.0 1 Oct 2025 for the test commands listed above.

[UnschooledGamer]

@stephanritscher Not sure, if the actual issue is with OpenSSH, as I used openssl genpkey -algorithm RSA -out RSA_private.pem -outpubkey RSA_pub_key with openssl version OpenSSL 3.2.2 4 Jun 2024 (Library: OpenSSL 3.2.2 4 Jun 2024) and tried importing the RSA_private.pem file in winScp (6.5.4), but that also shows error unrecognised key type.

Acode uses https://github.com/sshtools/maverick-synergy/ to provide SFTP Support.

[stephanritscher]

Yes, I used OpenSSL, not OpenSSH as well for generating the keys as written above.

[UnschooledGamer]

Yes, I used OpenSSL, not OpenSSH as well for generating the keys as written above.

I meant it's likely an issue with openSSH compatibility, as I think openSSH defines compatibility for the SSH implementation libraries like the one Acode uses ( https://github.com/sshtools/maverick-synergy/ ), Try generating PKCS#8 via openSSH.