> ## Documentation Index
> Fetch the complete documentation index at: https://docs.bytebase.com/llms.txt
> Use this file to discover all available pages before exploring further.
# Masking Algorithm
You may customize your data masking algorithm with the help of a predefined masking type while [creating a semantic type](/security/data-masking/semantic-types).
## Full mask
Mask the entire value and show **Substitute** value.
## Range mask
Mask several characters of a string and replace them with **Substitute** value.
## MD5 mask
Use MD5 algorithm together with **Salt** value to hash.
## Inner / Outer mask
* Inner mask: Mask `123456` to format like `12**56`, `1***56`.
* Outer mask: Mask `123456` to format like `**34**`, `*23***`.
