Data Masking Functions

Updated on 2022-11-18 GMT+08:00

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Data masking refers to the process of distorting sensitive information based on masking rules to protect sensitive privacy data.

mask_first_n(string str[, int n]) →varchar
Description: Returns the masked version of a string. The first n values are masked. Uppercase letters are converted to X, lowercase letters to x, and digits to n.
```
select mask_first_n('Aa12-5678-8765-4321', 4);
        _col0        
---------------------
 Xxnn-5678-8765-4321 
(1 row)
```
mask_last_n(string str[, int n]) →varchar
Description: Returns the masked version of a string. The last n values are masked. Uppercase letters are converted to X, lowercase letters to x, and digits to n.
```
select mask_last_n('1234-5678-8765-Hh21', 4);
        _col0        
---------------------
 1234-5678-8765-Xxnn 
(1 row)     
```
mask_show_first_n(string str[, int n]) →varchar
Description: Returns the masked version of a string. Only the first n characters are displayed. Uppercase letters are converted to X, lowercase letters to x, and digits to n.
```
select mask_show_first_n('1234-5678-8765-4321',4);
        _col0        
---------------------
 1234-nnnn-nnnn-nnnn 
(1 row)
```
mask_show_flairst_n(string str[, int n]) →varchar
Description: Returns the masked version of a string. Only the last n characters are displayed. Uppercase letters are converted to X, lowercase letters to x, and digits to n.
```
select mask_show_last_n('1234-5678-8765-4321',4);
        _col0        
---------------------
 nnnn-nnnn-nnnn-4321 
(1 row))
```

mask_hash(string|char|varchar str) →varchar

Description: Returns a hash value of a string. Hash values are consistent and can be used to join masked values across tables. For a non-string, NULL is returned.

select mask_hash('panda');
                              _col0                               
------------------------------------------------------------------
 a7cdf5d0586b392473dd0cd08c9ba833240006a8a7310bf9bc8bf1aefdfaeadb 
(1 row)

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