5.4. Encryption via Tables
The DES Public Key Encryption algorithm (FIPS 42-2) is driven by tables of permutations on a 64-bit block of data. I do not want to go into the algorithms, since they typically involve low-level bit fiddling for which SQL was never intended, but encryption is a class of functions for which they try to make it hard to find an inverse function.
A very simple, but surprisingly good, encryption is to use a table of integers between 0 and 7 (or 0 and 15 for Unicode) to determine how far to circular shift an ASCII character. Circular shift is a machine-level that shifts the bits right (or left) for (n) positions as if they were in a circle, so no bits are lost. For example, RgtRotate(‘01110111’, 3) = ‘11101110’.
CREATE TABLE ...
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