IOS/ES: Handle personalised tickets properly

IOS unpersonalises device-specific ("personalised") tickets prior to
storing them on the NAND.

Source/Core/Core/ec_wii.cpp

@@ -9,6 +9,7 @@
 
 #include "Core/ec_wii.h"
 
+#include <algorithm>
 #include <cstdio>
 #include <cstring>
 
@@ -179,6 +180,19 @@ const u8* EcWii::GetNGSig() const
   return BootMiiKeysBin.ng_sig;
 }
 
+std::array<u8, 16> EcWii::GetSharedSecret(const EcWii::ECCKey& peer_public_key) const
+{
+  EcWii::ECCKey shared_secret;
+  point_mul(shared_secret.data(), GetNGPriv(), peer_public_key.data());
+
+  std::array<u8, 20> sha1;
+  mbedtls_sha1(shared_secret.data(), shared_secret.size() / 2, sha1.data());
+
+  std::array<u8, 16> aes_key;
+  std::copy_n(sha1.cbegin(), aes_key.size(), aes_key.begin());
+  return aes_key;
+}
+
 void EcWii::InitDefaults()
 {
   memset(&BootMiiKeysBin, 0, sizeof(BootMiiKeysBin));