Getting Error using a SSH SFTP Site with Private Key

[Vission01]

@drudge

I have an SFTP site that uses a private key along with user/pass for authentication. I know my Credentials are working as I can use the native FTP Upload in N8N to upload files without issue.

Here is the Error:

connect: Cannot parse privateKey: Unsupported key format

N8N Details:

{
"errorMessage": "connect: Cannot parse privateKey: Unsupported key format",
"errorDetails": {},
"n8nDetails": {
"n8nVersion": "2.6.3 (Self Hosted)",
"binaryDataMode": "filesystem",
"stackTrace": [
"Error: connect: Cannot parse privateKey: Unsupported key format",
" at SftpClient.fmtError (/home/node/.n8n/nodes/node_modules/n8n-nodes-ftp-trigger/node_modules/ssh2-sftp-client/src/index.js:82:22)",
" at SftpClient.connect (/home/node/.n8n/nodes/node_modules/n8n-nodes-ftp-trigger/node_modules/ssh2-sftp-client/src/index.js:219:37)",
" at processTicksAndRejections (node:internal/process/task_queues:105:5)",
" at PollContext.poll (/home/node/.n8n/nodes/node_modules/n8n-nodes-ftp-trigger/nodes/FtpTrigger/FtpTrigger.node.ts:328:4)",
" at WorkflowExecute.executePollNode (/usr/local/lib/node_modules/n8n/node_modules/.pnpm/n8n-core@file+packages+core_@opentelemetry+api@1.9.0_@opentelemetry+sdk-trace-base@1.30_ec37920eb95917b28efaa783206b20f3/node_modules/n8n-core/src/execution-engine/workflow-execute.ts:1117:19)",
" at WorkflowExecute.runNode (/usr/local/lib/node_modules/n8n/node_modules/.pnpm/n8n-core@file+packages+core_@opentelemetry+api@1.9.0_@opentelemetry+sdk-trace-base@1.30_ec37920eb95917b28efaa783206b20f3/node_modules/n8n-core/src/execution-engine/workflow-execute.ts:1268:11)",
" at /usr/local/lib/node_modules/n8n/node_modules/.pnpm/n8n-core@file+packages+core_@opentelemetry+api@1.9.0_@opentelemetry+sdk-trace-base@1.30_ec37920eb95917b28efaa783206b20f3/node_modules/n8n-core/src/execution-engine/workflow-execute.ts:1685:27",
" at /usr/local/lib/node_modules/n8n/node_modules/.pnpm/n8n-core@file+packages+core_@opentelemetry+api@1.9.0_@opentelemetry+sdk-trace-base@1.30_ec37920eb95917b28efaa783206b20f3/node_modules/n8n-core/src/execution-engine/workflow-execute.ts:2328:11"
]
}
}

[Vission01]

A little Claude against the source code stated:

The issue is that when a privateKey is provided, it needs to be properly formatted for the SSH2 library. The SSH2 library expects the privateKey to be a Buffer or a properly formatted string. The error "Unsupported key format" typically occurs when:

The key format is not recognized (needs to be PEM, OpenSSH, or RFC4716 format)
The key needs to be converted from a string to a Buffer
The key might have incorrect line breaks or formatting
The line to be modified for properly handling the privateKey:

Lines in FtpTrigger.node.ts+29-6

Convert privateKey to Buffer: The SSH2 library works better with Buffer objects rather than strings for privateKeys
Handle escaped newlines: If the key contains literal \n characters (common when keys are stored as single-line strings), they're converted to actual newlines
Conditional authentication: Only include privateKey in the connection options if it's provided; otherwise use password authentication
Proper passphrase handling: The passphrase is only added when a privateKey is present
These changes should resolve the "Unsupported key format" error. The node will now properly parse and use SSH privateKeys in various formats (PEM, OpenSSH, etc.)

[Vission01]

@drudge - Do you know when your fixes might be released to npm?