How do I encode data in Excel to make it anonymous?

[Aiso]

I need to change names in Excel to make it anonymous to onlookers, but make
it transferrable back to the original name for those who know the code.

 

[Gary''s Student]

Keep the real names in an external file with sequentail numbers assigned to
them. The visible file will only have the numbers, but the real names will
be available to anyone who has the external file.

 

[DennisS]

If you know how to write user defined functions or macros you may use VBA
logical XOR (eXclusive OR) function to encode/decode your text.
e.g.
1 XOR 3 = 2
2 XOR 3 = 1

asc("A") XOR asc("z") = 59=asc(";")
asc(";") XOR asc("z") = 65 =asc("A")

Function DoXOR(XORWhat as string, WithWhat as string) as string

The function then XORs every character from XORWhat with every character
from WithWhat (cyclically).

First Function call encodes text, second run decodes it.
Not quite elegant though.