diff --git a/Cargo.toml b/Cargo.toml
index d346019..77870dd 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -15,10 +15,10 @@ rust-version = "1.56.0"
 default-target = "x86_64-pc-windows-msvc"
 
 [dependencies]
-windows-sys = { version = "0.48", features = [
+windows-sys = { version = "0.52", features = [
     "Win32_Foundation", "Win32_Security_Cryptography",
     "Win32_Security_Authentication_Identity", "Win32_Security_Credentials",
     "Win32_System_Memory"] }
 
 [dev-dependencies]
-windows-sys = { version = "0.48", features = ["Win32_System_SystemInformation", "Win32_System_Time"] }
+windows-sys = { version = "0.52", features = ["Win32_System_SystemInformation", "Win32_System_Time"] }
diff --git a/src/crypt_prov.rs b/src/crypt_prov.rs
index 9e5cd0c..5c383ba 100644
--- a/src/crypt_prov.rs
+++ b/src/crypt_prov.rs
@@ -5,7 +5,7 @@ use std::ptr;
 use std::slice;
 
 use windows_sys::Win32::Security::Cryptography;
-use windows_sys::Win32::System::Memory;
+use windows_sys::Win32::Foundation;
 
 use crate::crypt_key::CryptKey;
 use crate::Inner;
@@ -204,7 +204,7 @@ impl<'a> ImportOptions<'a> {
 
             let mut key = 0;
             let res = Cryptography::CryptImportKey(self.prov.0, buf, len, 0, self.flags, &mut key);
-            Memory::LocalFree(buf as isize);
+            Foundation::LocalFree(buf as *mut _);
 
             if res != 0 {
                 Ok(CryptKey::from_inner(key))
@@ -239,7 +239,7 @@ impl<'a> ImportOptions<'a> {
             let pkey = pkey.PrivateKey;
 
             let res = self.import(slice::from_raw_parts(pkey.pbData, pkey.cbData as usize));
-            Memory::LocalFree(buf as isize);
+            Foundation::LocalFree(buf as *mut _);
             res
         }
     }