Oracle uses DBMS_ Crypto realizes MD5 value calculation

background

In the work , You need to check the data in the database lob Type field MD5 Value calculation , To judge lob Is the content unique . There are many ways to achieve it , Such as developing programs to achieve 、 Database implementation . Here the Oracle Of DBMS_CRYPTO Package implementation .

DBMS_CRYPTO brief introduction

DBMS_CRYPTO Contains basic encryption functions and procedures . To use this package correctly and safely , Requires a general level of security expertise .
DBMS_CRYPTO Package support for common Oracle Data types are encrypted and decrypted , Include RAW And big objects (lob), Like images and sounds . say concretely , It supports blob and clob. Besides , It also provides global support for encrypting data across different database character sets .

The cryptographic algorithms supported are as follows ：

• Data Encryption Standard (DES), Triple DES (3DES, 2-key and 3-key)

• Advanced Encryption Standard (AES)

• MD5, MD4, SHA-1, and SHA-2 cryptographic hashes

• MD5, SHA-1, and SHA-2 Message Authentication Code (MAC)

The process

-- Empowerment 
grant execute on DBMS_CRYPTO to USERNAME;

-- Confirm whether you have this permission 
SELECT * FROM user_tab_privs WHERE table_name = 'DBMS_CRYPTO';

-- Generate MD5
select lower(rawtohex(dbms_crypto.hash(utl_raw.cast_to_raw(' Zhang San '),2 /*dbms_crypto.HASH_MD5*/))) from dual;

Reference resources

https://docs.oracle.com/database/121/ARPLS/d_crypto.htm#ARPLS65672

https://blog.csdn.net/rznice/article/details/7402850