The Private key used for authentication.
Remarks
The PrivateKey property is used when you want to authenticate with the server using your private/public key pair instead of using a
Password. This is a feature that should be supported by all SFTP servers.
The idea of using keys is this: you own a
private key (which no one else knows). You supply the server with the
public key that corresponds to your
private key. Once you initiate a connection, wodSFTP will request
PublicKey authentication. The server will check its internal list of public keys (usually stored in
-/.ssh/authorized_keys2 or
-/.ssh2/authorized files) and if a match is found, it will send a request to wodSFTP to prove that you own the
private key. Internally, wodSFTP will sign some data using the key that you provided and the server will check the signature. If they match, it will allow you to log in. Some servers will also require you to enter a password, in which case this makes the server even more secure.
To generate a PrivateKey that you can use with the server, use the Keys object (included in the setup package) like this (VB sample):
Dim key As New wodSFTPKeyLib.Keys
key.Generate RSAkey ' 1024 bits is default
key.Save RSAkey, "C:\my_rsa_key.txt", "My secret password"
The above sample will generate your private key and store it to file on disk, protected with password. You can immediately continue your code like this:
Sftp.Login = "johndoe"
Sftp.PrivateKey = key ' or also key.PrivateKey(RSAkey)
Sftp.Authentication = authPubkey
.......
Sftp.Connect
Since generation of keys may be a lengthy process (for large bit numbers it can take a few seconds), you shouldn't generate it every time you need to use it. Rather, since we saved it, you should try to load it from the disk. A typical scenario would be:
Dim key As New wodSFTPKeyLib.Keys
On Error Resume Next
' try to load previously saved key
key.Load "C:\my_rsa_key.txt", "My secret password"
If Err <> 0 Then 'key was not saved yet
key.Generate RSAkey ' 1024 bits is default
key.Save RSAkey, "C:\my_rsa_key.txt", "My secret password"
' next time you run this code it will be able to load it from the disk,
' so expensive Generate will not be called anymore.
End If
Now that you have created your PrivateKey, you should let the server know about it. You should do this by pasting your
public key to the appropriate files on the server. For SFTP servers (version 2), these are:
-/.ssh2/authorization which should have a line of text
Key somefile.pub in a separate line of the file,
-/.ssh2/somefile.pub which should contain your public key, as returned by the
Keys.PublicKeySSH property.
For OpenSSH servers, you should paste the contents of the Keys.PublicKeyOpenSSH property to:
-/.ssh/authorized_keys2 as a new line in the file.
For VC users, you can prepare a returned key (loaded from file, for example) by converting it to a SAFEARRAY like this:
(Buffer holds key data, and Bufsize holds key length)
SAFEARRAY
*psa
; SAFEARRAYBOUND rgsabound
[1]; char HUGEP
*data
; rgsabound
[0].
lLbound=0; rgsabound
[0].
cElements=Bufsize
; psa
= SafeArrayCreate
(VT_UI1
,1,rgsabound
); if (!psa
) return WSA_NOT_ENOUGH_MEMORY
; SafeArrayAccessData
(psa
, (void HUGEP
* FAR
*)&data
); memcpy(data
,Buffer
, Bufsize
); SafeArrayUnaccessData
(psa
); VARIANT var
; var.
vt =VT_ARRAY
| VT_UI1
; var.
parray=psa
;
and now you can pass this VARIANT to the PrivateKey property or you can pass LPDISPATCH from the IKeys object directly in same way:
VARIANT var;
var.vt = VT_DISPATCH;
var.pdispVal = (LPDISPATCH)your_keys_object_instance
and it will work too.
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