MSSQL Hash Algorithms

MSSQL Hash Algorithms:

There are two forms of encryption algorithms: one-way and two-way. Two-way algorithms allow you to encrypt and decrypt data. One-way algorithms will only encrypt data without any ability to decrypt.

A hash algorithm is the simplest way to encrypt data, however, once encrypted, you can’t decrypt the data. Your data remains secure, ensuring that in order to “decrypt” the contents of a column you would first have to know the original data value.

--Different hash algorithms produce different hash values
DECLARE @TEST_VAL varchar(100)
SELECT @TEST_VAL = 'SQL Server'
SELECT HashBytes('MD5', @TEST_VAL)
SELECT @TEST_VAL = 'SQL Server'
SELECT HashBytes('SHA1', @TEST_VAL)
GO

--Hash values are case sensitive
DECLARE @TEST_VAL varchar(100)
SELECT @TEST_VAL = 'sql'
SELECT HashBytes('SHA1', @TEST_VAL)
SELECT @TEST_VAL = 'SQL'
SELECT HashBytes('SHA1', @TEST_VAL)
GO

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