About Substitute
A substitution cipher allowing you to specify bytes to replace with other byte values. This can be used to create Caesar ciphers but is more powerful as any byte value can be substituted, not just letters, and the substitution values need not be in order. Enter the bytes you want to replace in the Plaintext field and the bytes to replace them with in the Ciphertext field. Non-printable bytes can be specified using string escape notation. For example, a line feed character can be written as either \n or \x0a. Byte ranges can be specified using a hyphen. For example, the sequence 0123456789 can be written as 0-9. Note that blackslash characters are used to escape special characters, so will need to be escaped themselves if you want to use them on their own (e.g.\\).
Input: text. Output: text.
Format reference: Substitute background and specification
Example
Use “Try example” to load this public sample and its settings, then run it.
Settings used in this example
| Parameter | Example value | Input and choices |
|---|---|---|
| Plaintext | "abcdefghijklmnopqrstuvwxyz" | Escape sequences such as \n, \r and \t are supported |
| Ciphertext | "zebrascdfghijklmnopqtuvwxy" | Escape sequences such as \n, \r and \t are supported |
| Ignore case | false | On or off |
Input
flee at once. we are discovered!
Result
siaa zq lkba. va zoa rfpbluaoar!
Parameters
| Parameter | Default value | Input and choices |
|---|---|---|
| Plaintext | "ABCDEFGHIJKLMNOPQRSTUVWXYZ" | Escape sequences such as \n, \r and \t are supported |
| Ciphertext | "XYZABCDEFGHIJKLMNOPQRSTUVW" | Escape sequences such as \n, \r and \t are supported |
| Ignore case | false | On or off |
Before interpreting the result
Use the exact key encoding, mode, padding and IV expected by the source system. Historical ciphers are useful for learning and analysis. Encoding alone provides no confidentiality.
How to use this page
- Paste your input or open a local file.
- Adjust tool options if needed, then choose Run tool.
- Copy the result or download the original output bytes.
Inputs and results are not added to the public catalogue or saved in the URL. Processing happens in your browser; HTTP Request and DNS over HTTPS send the requests you explicitly run. Files up to 128 MiB can be opened; decompression and image tools may have smaller processing limits. Large results have a shortened preview. Text and HTML downloads use UTF-8; binary downloads preserve output bytes. Pasted text follows browser newline handling; open a file when exact input bytes matter.