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In SSH the client publishes his public encryption key into the server authorized_keys file for a given user. I am interested in understanding better how the public key is used context of authentication. At which stage is it used? Are there digest messages being exchanged? I Googled it and found no clear answer to this questions. Thanks!

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up vote 2 down vote accepted

The SSH protocol is described in excruciating detail in a series of five RFCs:

The authentication protocol is RFC 4252 (

If you're interested in seeing what SSH is sending back and forth, you can run it with the -v parameter to see what it's doing.

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