- By default, spaces are preserved.
- Lower case ascii characters are replaced with lower case ascii letters.
- Upper case ascii characters are replaced with upper case ascii letters.
- Digits are replaced with digits.
- Any other ascii character in the code point range 32 to 126 (0x20 - 0x7e) is replaced with either an alphanumeric character, or "_", '-", or "+".
- Any other character is replaced with a Latin-1 character in the range of (0x20 - 0x7e, or 0xa0 - 0xff).
For more information, check out the Copycat documentation.
PS: Worried about your transformation outputs being inferred? It's highly unlikely (and computationally infeasible), but Copycat does supports salt with setSalt - read more about working with sensitive inputs here.