private static SslProtocols LoadSecureProtocolConfiguration(SslProtocols defaultValue)
{
if (!s_disableSystemDefaultTlsVersions)
{
defaultValue = SslProtocols.None;
}
else if (!s_disableStrongCrypto)
{
defaultValue = SslProtocols.Tls13 | SslProtocols.Tls12 | SslProtocols.Tls11 | SslProtocols.Tls;
}
else
{
defaultValue = SslProtocols.Tls | SslProtocols.Ssl3;
}
if (!s_disableStrongCrypto || !s_disableSystemDefaultTlsVersions)
{
string appSetting = RegistryConfiguration.AppConfigReadString(RegistryLocalSecureProtocolName, null);
SecurityProtocolType value;
if (Enum.TryParse(appSetting, out value))
{
ValidateSecurityProtocol(value);
defaultValue = (SslProtocols)value;
}
}
return(defaultValue);
}
private static void LoadDisableStrongCryptoConfiguration()
{
try {
bool disableStrongCryptoInternal = false;
int schUseStrongCryptoKeyValue = 0;
if (LocalAppContextSwitches.DontEnableSchUseStrongCrypto)
{
//.Net 4.5.2 and below will default to false unless the registry key is specifically set to 1.
schUseStrongCryptoKeyValue =
RegistryConfiguration.GlobalConfigReadInt(strongCryptoValueName, 0);
disableStrongCryptoInternal = schUseStrongCryptoKeyValue != 1;
}
else
{
// .Net 4.6 and above will default to true unless the registry key is specifically set to 0.
schUseStrongCryptoKeyValue =
RegistryConfiguration.GlobalConfigReadInt(strongCryptoValueName, 1);
disableStrongCryptoInternal = schUseStrongCryptoKeyValue == 0;
}
if (disableStrongCryptoInternal)
{
// Revert the SecurityProtocol selection to the legacy combination.
s_SecurityProtocolType = SecurityProtocolType.Tls | SecurityProtocolType.Ssl3;
}
else
{
s_SecurityProtocolType =
SecurityProtocolType.Tls12 | SecurityProtocolType.Tls11 | SecurityProtocolType.Tls;
string appSetting = RegistryConfiguration.AppConfigReadString(secureProtocolAppSetting, null);
SecurityProtocolType value;
try {
value = (SecurityProtocolType)Enum.Parse(typeof(SecurityProtocolType), appSetting);
ValidateSecurityProtocol(value);
s_SecurityProtocolType = value;
}
// Ignore all potential exceptions caused by Enum.Parse.
catch (ArgumentNullException) { }
catch (ArgumentException) { }
catch (NotSupportedException) { }
catch (OverflowException) { }
}
disableStrongCrypto = disableStrongCryptoInternal;
}
catch (Exception e)
{
if (e is ThreadAbortException || e is StackOverflowException || e is OutOfMemoryException)
{
throw;
}
}
}
