Key authentication that uses the key Putty key generated.

Document ID : KB000121334
Last Modified Date : 19/11/2018
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Question:
The customer is looking into the usage of the key authentication that the key is generated by the PuTTY. 

During that, the PuTTY has the feature that it generated the key as PuTTY type(*.PPK file), but PAM seems not to be able to use the key type. 

When the customer tries to use the key of the "PuTTY" type and the "OpenSSH" type by the "Access by Putty with the key authentication" and the "Register the target account", the result is as below. 

<PuTTY type> 
- "Access by Putty with the key authentication": Success to access. 
- "Register the target account": Can't be saved with the "PAM-CM-3481: An invalid private key was specified." 

<OpenSSH type> 
- "Access by Putty with the key authentication": Can't access the box because of the "unable to use key file". 
- "Register the target account": Success to save the target account. 


[Question] 
- Is it possible to auto login by the key authentication of PuTTY? 
- If not possible, is it a design behavior? 
- If possible, the customer would like to know how to set the configuration.
Answer:
PuTTY's PPK type key is not supported by PAM. 
Also, the PuTTY cannot use the converted private key of the OpenSSH type. Hence, it is not possible to meet the end user's expectation. 
We asked the customer to raise the idea if he expects it in future version.