This is an extension of my previous question - How to securely and efficiently store SSN in a database?
The idea is, I have social security numbers that I want to securely hash, and then insert into a column, and index that column. Then I can quickly find users who have multiple accounts with the same SSN.
I was on my way using PBKDF2 and SHA256, but I completely missed that MySql limits BIT columns to 64bits. I have 256bits. I'm not sure where to go. Any advice is appreciated.