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SQL Server Tips by Burleson |
XP_CRYPTOAPI Usage
To compile the class you will need Microsoft Visual C++ 6.0 or later
installed.
You should also ensure that you have a recent MS Platform SDK
installed and configured.
Follow the normal procedure to register the DLL. You should register
all the XP’s as implemented in the module “XPCrypt.cpp” using the
TSQL statement “sp_addextendedproc”.
A lot of the XP’s return a variable sized output parameter e.g. the
encrypted data, signature, hash or HMAC. To determine the maximum
size for these variables you should call the function using the
maximum size of data for the input and use the size of the output
parameter for your definitions. This ensures that output data does
not get truncated. Also since the encrypted data can be bigger than
the plaintext input parameters, special care must be taken when
designing tables which will stored encrypted data so that they will
not cause problems with the inherent limit of 8000 characters in
TSQL.
The above book excerpt is from:
Super SQL
Server Systems
Turbocharge Database Performance with C++ External Procedures
ISBN:
0-9761573-2-2
Joseph Gama, P. J. Naughter
http://www.rampant-books.com/book_2005_2_sql_server_external_procedures.htm |
