Currently if you try compare tables with encrypted columns, you get a cast error. It doesn't tell you that encryption is not supported. In fact it took your help desk two weeks to tell me it doesn't and suggest I post a feature request here. I do not know what mechanism you use to connect to SQL Server, but all of my other SQL Server clients support it seamlessly. That includes ODBC. Even if you didn't want to enable decrypting the data you at least could just allow the comparison on the encrypted values, and let the user worry about whether or not the keys are the same. This is a major feature of SQL Server that has been around for several years. It is quickly becoming the standard to encrypt data. On top of this, your documentation implies that it works on encrypted data. So much so, that your own tech support thinks it does.