The first thing I needed to do was grant access to the dbms_crypto package which is owned by SYS. Not a problem. Then I called the hash function. Seemed easy enough. I wanted it to do a SHA256 on my plain text. For some reason, I could not get the function to recognize HASH_SH256. It is supposed to be defined in the dbms_crypto package. But Oracle kept complaining.
I needed to get this project moving. So I just hacked the hash type and passed in a 4. I have it on good authority that 4 means perform a SHA256. Eventually I should figure out what the problem here is. Now I got a bunch of hashes. But they are in raw format. Not too good to look at.
After running the raw hashes through rawtohex() plus a to_char(), I am good to go. I was surprised that all the hashes have the same length. I know the upper bound is supposed to be 256 bits wide (i.e. 64 characters). However I thought some of the hashes might be shorter. Nope. all were the same size.
What input data did I pass to the hash function? Heh. I grabbed a bunch of sentences from the book Pride and Prejudice. That is a story for another blog post.
