The invention relates to a data 
encryption / decryption and desensitization operation engine, a working method thereof and a computer readable storage medium. The working method of the data 
encryption / decryption and desensitization operation engine comprises the following steps of: 10, intercepting 
SQL statements by an SDK 
client integrated to a business 
system, judging whether the 
SQL statements need to be rewritten or not according to a 
metadata configuration, directly sending requests to a 
database by the 
SQL statements not needing to be rewritten, and requesting a 
security service by the SQLstatements needing to be rewritten so as to be rewritten; 20, obtaining the SQL statements needing to be rewritten by the 
security service, completing SQL statement 
rewriting according to the 
metadata configuration, returning the rewritten SQL statements to the SDK 
client, and calling the rewritten SQL statements to initiate a request to the 
database by the SDK 
client; and 30, for the request involved in desensitization 
processing, taking a 
database expansion function as an RPC client to call an operation component of an RPC operation service so as to return a result. By using a client SDK mode, the business 
unavailability risk, caused by stability, of transparent data 
encryption gateway agency mode is avoided.