Libsodium-net - Unable to load DLL 'libsodium.dll

Question

I installed Libsodium-net through NuGet and am able to include Sodium in my classes, but when I try to run it, I get

An exception of type 'System.DllNotFoundException' occurred in Sodium.dll but was not handled in user code

Additional information: Unable to load DLL 'libsodium.dll': The specified module could not be found. (Exception from HRESULT: 0x8007007E)

I am just trying to run the sample code from the gitbooks documentation https://bitbeans.gitbooks.io/libsodium-net/content/password_hashing/index.html

const string PASSWORD = "Correct Horse Battery Staple";
const string SALT = "qa~t](84z<1t<1oz:ik.@IRNyhG=8q(o";
const long OUTPUT_LENGTH = 512;

//this will produce a 512 byte hash
var hash = PasswordHash.ScryptHashBinary(PASSWORD, SALT,      PasswordHash.Strength.Medium, OUTPUT_LENGTH);

Answer 1

I had the same problem and solved it using Jørn Wildt's answer given here.

It turns out that ASP.NET doesn't make shadow copies of unmanaged DLLs such as libsodium.dll and libsodium-64.dll.

Sodium.dll (the managed code) tries to load the DLLs from either the same directory as the shadow copy of Sodium.dll (which is not going to work) - or some where in the PATH environment variable's directories.

My solution was to add the AppDomain \Bin directory to the path before calling any Sodium code:

string path = Environment.GetEnvironmentVariable("PATH");
string binDir = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "Bin");
Environment.SetEnvironmentVariable("PATH", path + ";" + binDir);

As Reuben commented on the answer; I added the above code in my Application_Start method of my Global.asax.