ED25519 private key loading failed: Keys(SshKey(Encoding(CharacterEncoding))) error

[Star-caorui]

Issue Description: Unable to Use ED25519 Key for SSH Login

When attempting to use an ED25519 private key for SSH login to my server, I encounter the following error:

error: Keys(SshKey(Encoding(CharacterEncoding)))
Could not read the private key

Here is some relevant information about my environment:

Server Information:

• OS: Arch Linux 6.12.9-arch1-1 #1 SMP PREEMPT_DYNAMIC Fri, 10 Jan 2025 00:39:41 +0000 x86_64 GNU/Linux
• OpenSSH Version: OpenSSH_9.9p1
• OpenSSL Version: OpenSSL 3.4.0 22 Oct 2024

SSH Private Key Details:

My private key appears to be in the OpenSSH format:

-----BEGIN OPENSSH PRIVATE KEY-----
XXXXXXXXX== (this looks like Base64-encoded content)
-----END OPENSSH PRIVATE KEY-----

I would greatly appreciate your help resolving this issue. If further information or testing is required, please let me know.

Thank you for your help and time.

Version: 1.0.220
Platform: macOS arm64 24.2.0
Plugins: none
Frontend: xterm-webgl

[Eugeny]

Could you please generate a new key in the same format that reproduces the issue and post it here?

[Star-caorui]

Sure. I use ssh-keygen command on Arch Linux.

-----BEGIN OPENSSH PRIVATE KEY-----
b3BlbnNzaC1rZXktdjEAAAAABG5vbmUAAAAEbm9uZQAAAAAAAAABAAAAMwAAAAtzc2gtZW
QyNTUxOQAAACBHPVbd5kPw1PHe3T+EEtE4Q21piEHz9z8JpYKJjD2lswAAAJgEjpxkBI6c
ZAAAAAtzc2gtZWQyNTUxOQAAACBHPVbd5kPw1PHe3T+EEtE4Q21piEHz9z8JpYKJjD2lsw
AAAEBjcfJFEf9F+Suc17tZ2kG3cuKLhTP0UeD2u3F5WdhHwkc9Vt3mQ/DU8d7dP4QS0ThD
bWmIQfP3PwmlgomMPaWzAAAAE3N0YXJAYmouaW5ldGVjaC5mdW4BAg==
-----END OPENSSH PRIVATE KEY-----

[Star-caorui]

In Version: 1.0.215, everything worked perfectly without any errors.

Starting from Version: 1.0.216 and in all later versions, including Version: 1.0.220 , I began to see the following error:

Error: Keys(SshKey(Encoding(CharacterEncoding)))
Could not read the private key

In Version: 1.0.216, despite the error, I was still able to connect successfully using the ED25519 private key.

However, starting from Version: 1.0.218 and including Version: 1.0.220 , the same error occurs, but I am no longer able to connect with the ED25519 private key.

I hope this helps you identify the issue.

Best regards.

[Eugeny]

@Star-caorui the test key you posted is working fine in the latest release (1.0.220)

[Star-caorui]

Thank you for the support! I’ve confirmed that the newly generated key works perfectly. However, the previous ed25519 key couldn’t be used, but since the issue is now resolved, I will go ahead and close it.

For reference, I’m attaching the problematic (now deprecated) key here.

Best regards!

-----BEGIN OPENSSH PRIVATE KEY-----
b3BlbnNzaC1rZXktdjEAAAAABG5vbmUAAAAEbm9uZQAAAAAAAAABAAAAMwAAAAtzc2gtZW
QyNTUxOQAAACD2TvUAi4NJBWXBvDkzbLiIjgjeMzhTz9cUleJn2zRWKAAAAJi1GedGtRnn
RgAAAAtzc2gtZWQyNTUxOQAAACD2TvUAi4NJBWXBvDkzbLiIjgjeMzhTz9cUleJn2zRWKA
AAAEDBi49uVXZzDhN8JohiYkBdezFWbCAw6iCS2JRA4J0ujfZO9QCLg0kFZcG8OTNsuIiO
CN4zOFPP1xSV4mfbNFYoAAAAFHN0YXJfQLLcyPHI8cjxtcS158TUAQ==
-----END OPENSSH PRIVATE KEY-----

[Eugeny]

Found it - the issue was with a key comment string that isn't UTF-8

[Eugeny]

ref RustCrypto/SSH#331