save passwords securely

[#1]

Does anyone have a secure way to store passwords so users don't have to enter their password every time?  

I don't want to just store the password as plain text in a preferences file or anything like that.  

Names default to here(1);
nw = new window("Login", 
	lineupbox(ncol(2), 
		textbox("Username"), teb_uid = texteditbox("Vincent", <<Set Width(200)), 
		textbox("Password"), teb_pwd = texteditbox("thisisapassword", <<Width(200), <<Password Style(1))
	), 
	cb_save = checkbox({"Remember Me"}), 
	buttonbox("OK", 
		uid = teb_uid << Get Text();
		pwd = teb_pwd << Get Text();
		nw << close window();
	)
);

[#2]

On Windows I believe this code could be re-created with JSL and the command line to interact with the windows credential manager, could be wrong.  Maybe someday I will take this on; sharing it here in case someone else figures it out first. :)

#include <windows.h>
#include <wincred.h>
#include <tchar.h>
#pragma hdrstop

void main ()
{
    { //--- SAVE
        char* password = "brillant";        DWORD cbCreds = 1 + strlen(password);
        CREDENTIALW cred = {0};        cred.Type = CRED_TYPE_GENERIC;        cred.TargetName = L"FOO/account";        cred.CredentialBlobSize = cbCreds;        cred.CredentialBlob = (LPBYTE) password;        cred.Persist = CRED_PERSIST_LOCAL_MACHINE;        cred.UserName = L"paula";
        BOOL ok = ::CredWriteW (&cred, 0);        wprintf (L"CredWrite() - errno %d\n", ok ? 0 : ::GetLastError());
        if (!ok) exit(1);
    }
    { //--- RETRIEVE        PCREDENTIALW pcred;        BOOL ok = ::CredReadW (L"FOO/account", CRED_TYPE_GENERIC, 0, &pcred);        wprintf (L"CredRead() - errno %d\n", ok ? 0 : ::GetLastError());
        if (!ok) exit(1);        wprintf (L"Read username = '%s', password='%S' (%d bytes)\n", 
                 pcred->UserName, (char*)pcred->CredentialBlob, pcred->CredentialBlobSize);
        // must free memory allocated by CredRead()!
        ::CredFree (pcred);
    }
}

From kkm here:

https://stackoverflow.com/questions/9221245/how-do-i-store-and-retrieve-credentials-from-the-windows...

[#3]

Here is a version that uses an available module in powershell, maybe that is an option?

Names default to here(1);

loadmodule = "
		if (!(Get-Module -ListAvailable -Name CredentialManager)) {
			Install-Module CredentialManager -force -Scope CurrentUser
		}
		";


//Function to run command in powershell, strips trailing line breaks
RunPowershell = Function( {command},
	Regex(RunProgram(
		Executable( "powershell.exe" ),
		Options( {"/c", command } ),
		ReadFunction( "text" )
	), "^(.*?)[\r\n]+$", "\1")
);


// Set password
SetPass = Function( {target,user,pass},
	RunPowershell(
		"$target = '" || target || "'
		$usr = '" || user || "'
		$pswd = '" || pass || "'
		" || loadmodule || "
		New-StoredCredential -Target $target -UserName $usr -Password $pswd"
	);
	1; //password is returned as free text, don't return the response
);

// Get password
GetPass = Function( {target},
	RunPowershell(
		"$target = '" || target || "'
		" || loadmodule || "
		$creds = Get-StoredCredential -Target $target

		$creds.GetNetworkCredential().Password"
	)
);

// Get username
GetUser = Function( {target},
	RunPowershell(
		"$target = '" || target || "'
		" || loadmodule || "
		$creds = Get-StoredCredential -Target $target

		$creds.GetNetworkCredential().UserName"
	)
);

// Set and retrieve credentials
SetPass("testcredential", "myusername3", "mypassword3");
GetPass("testcredential");
GetUser("testcredential");

//You can delete these test credentials using the 'windows credential store'.

[#4]

I take an obfuscation-style route.  I convert characters to numbers, then feed these numbers into a mathematical formula to generate an 'encrypted' representation. 

I tend to use the technique more for software license codes rather than user passwords.  So I will take a product name or code combined with site ID information, plus an expiry date,  build a numeric representation and parse that through a complex mathematical formula: the final output might be something like 1143932720966.