I need to encrypt byte arrays blobs fields of approx 50k to 100k each in .net with a public key then store in SQL/Server thendestroy original data. When the data is retrieved by the ultimate owner, it would be with a key that only they have (I don't).
The problem is that I need all records to be encrypted with the same key so the owner can decrypt fields with set logic (group of records, not one record at a time).
I'm reading RSA is too slow to be practical for such large data and that RSA is typically used only for encrypting an symmetric key. This would work for me if I was decrypting one record at a time, but that is not the case and where I am stuck.
So, if asymmetric won't work, what is another/best way to solve this problem?