Can anyone tell me the name of this cipher please? Can anyone tell me the name of this cipher please?
I know it's a simple substitution cipher, I just don't know the name of it.

Cipher Key:

help


Cipher alphabet:

a|b|c|d|e|f|g|h|i|j|k|l|m|n|o|p|q|r|s|t|u|v|w|x|y|z
h|e|l|p|a|b|c|d|f|g|i|j|k|m|n|o|q|r|s|t|u|v|w|x|y|z


Text:

this is a test


Cipher text:

tdfs fs h tast


I think I have found the answer: a Caesar variant, a "Mixed Alphabet" substitution cipher.
Does it have a specific name?
It's called a keyword cipher.  See this question for some ways to break it.