SFTP Linked service using Public & Private Keys

Hi @Madhukar Muddasani
Welcome to Microsoft Q&A and thank you for posting your question.

The error Invalid Sftp credential provided for 'SshPublicKey' authentication type. Invalid private key file. usually occurs when the SSH private key format or configuration does not meet Azure Data Factory (ADF) requirements for SFTP linked services.

Common Causes and Fixes

Private Key Format Ensure your private key is in the correct format (OpenSSH or PEM) and includes the proper header and footer lines. ADF does not accept PuTTY .ppk files. Convert .ppk to OpenSSH using PuTTYgen or ssh-keygen.

Passphrase Keys encrypted with a passphrase are not supported. Remove the passphrase using: ssh-keygen -p -f id_rsa

Key Vault Secrets If storing the key in Azure Key Vault, upload the entire private key file as a base64-encoded secret. Avoid escaping newlines or adding BOM.

Public Key Verification Verify that the public key has been correctly added to the SFTP server’s authorized_keys. Test connectivity from the same Integration Runtime machine using: sftp -i id_rsa ******@sftp.example.com

Permissions Check the permissions of the key files and ensure they are accessible by the service.

Networking and IR Ensure outbound TCP/22 is allowed from your Integration Runtime host. Use Self-hosted IR if the SFTP server is in a private network or requires IP allowlisting.

If the issue persists, please provide more details about the error messages and the configuration you are using.

Official Documentation

• https://learn.microsoft.com/azure/data-factory/connector-sftp
• https://learn.microsoft.com/azure/data-factory/connector-troubleshoot-ftp-sftp-http

if still issue persist, please share required details in private message

Ensure that your private key is in the correct format (PEM) and not encrypted with a passphrase. Also, verify that the public key has been correctly added to the SFTP server. If the issue persists, check the permissions of the key files and ensure they are accessible by the service. If you still encounter problems, please provide more details about the error messages and the configuration you are using.