AE with enclaves - multi-platform and .NET Standard 2.1 support

src/Microsoft.Data.SqlClient/netcore/src/Microsoft/Data/SqlClient/AlwaysEncryptedEnclaveProviderUtils.cs

@@ -62,7 +62,7 @@ internal sealed class KeyConverter
         //     BCRYPT_RSAKEY_BLOB   header
         //     byte[ExponentSize]   publicExponent      
         //     byte[ModulusSize]    modulus             
-        private readonly struct RSAPublicKeyBlob
+        private sealed class RSAPublicKeyBlob
         {
             // Size of an RSA public key blob
             internal static readonly int Size = 539;
@@ -76,11 +76,24 @@ internal sealed class KeyConverter
             internal static readonly int ModulusOffset = HeaderSize;
         }
 
+        // Extracts the public key's modulus and exponent from an RSA public key blob
+        // and returns an RSAParameters object
+        internal static RSAParameters RSAPublicKeyBlobToParams(byte[] keyBlob)
+        {
+            Debug.Assert(keyBlob.Length == RSAPublicKeyBlob.Size,
+                $"RSA public key blob was not the expected length. Actual: {keyBlob.Length}. Expected: {RSAPublicKeyBlob.Size}");
+            return new RSAParameters()
+            {
+                Exponent = keyBlob.Skip(RSAPublicKeyBlob.ExponentOffset).Take(RSAPublicKeyBlob.ExponentSize).ToArray(),
+                Modulus = keyBlob.Skip(RSAPublicKeyBlob.ModulusOffset).Take(RSAPublicKeyBlob.ModulusSize).ToArray()
+            };
+        }
+
         // The ECC public key blob is structured as follows:
         //     BCRYPT_ECCKEY_BLOB   header
         //     byte[KeySize]        X     
         //     byte[KeySize]        Y         
-        private readonly struct ECCPublicKeyBlob
+        private sealed class ECCPublicKeyBlob
         {
             // Size of an ECC public key blob
             internal static readonly int Size = 104;
@@ -91,24 +104,11 @@ internal sealed class KeyConverter
         }
 
         // Magic numbers identifying blob types
-        private readonly struct KeyBlobMagicNumber
+        private sealed class KeyBlobMagicNumber
         {
             internal static readonly byte[] ECDHPublicP384 = new byte[] { 0x45, 0x43, 0x4b, 0x33 };
         }
 
-        // Extracts the public key's modulus and exponent from an RSA public key blob
-        // and returns an RSAParameters object
-        internal static RSAParameters RSAPublicKeyBlobToParams(byte[] keyBlob)
-        {
-            Debug.Assert(keyBlob.Length == RSAPublicKeyBlob.Size,
-                $"RSA public key blob was not the expected length. Actual: {keyBlob.Length}. Expected: {RSAPublicKeyBlob.Size}");
-            return new RSAParameters()
-            {
-                Exponent = keyBlob.Skip(RSAPublicKeyBlob.ExponentOffset).Take(RSAPublicKeyBlob.ExponentSize).ToArray(),
-                Modulus = keyBlob.Skip(RSAPublicKeyBlob.ModulusOffset).Take(RSAPublicKeyBlob.ModulusSize).ToArray()
-            };
-        }
-
         // Extracts the public key's X and Y coordinates from an ECC public key blob
         // and returns an ECParameters object
         internal static ECParameters ECCPublicKeyBlobToParams(byte[] keyBlob)