ForHosting KIT · Developer Utilities

Trithemius cipher encoder and decoder

This Trithemius cipher tool encrypts or decrypts text with the classic progressive Caesar substitution that increases the shift by one for each successive letter, following the historical tabula recta idea without needing a separate keyword.

● BetaFree · in your browser

Run — free How it works & API

Use it from WebAPIEmailTelegramApp soon

The first alphabetic character uses shift zero, the second uses shift one, the third uses shift two, and so on with modular wrap around a twenty-six letter alphabet, so the same plaintext letter can map to different ciphertext letters depending only on how many letters came before it. Case is preserved on every letter, while spaces, digits, punctuation, and other non-letters pass through unchanged and never advance the letter index, which keeps readable phrase structure around the scrambled alphabet. The engine is fully deterministic with no network calls, no random salts, and no date-dependent shortcuts, so teaching fixtures and CI goldens stay bitwise stable across workers and browser widgets. A standard check is Hello World encrypting under progressive shifts and decrypting back to the original under the same rule. Use it free in the browser for CTF warm-ups, history-of-crypto lessons, and reversible puzzle worksheets, or call the API at $0.002 per successful request when pipelines need reproducible Trithemius transforms in automated services.

How to use it

Enter your values in the form above. The tool checks them before calculating and shows the result on the same page.

Check your inputs

Use the labels and units shown next to each field. If something is missing or outside the allowed range, the page points to the field to fix.

Use it again or automate it

Use the browser tool for individual checks and the API when you need the same capability in an automated workflow.

What you can do with it

Get an answer now

Enter one set of values and see the result without building a spreadsheet or script.

Compare scenarios

Change one value at a time and rerun the calculation to understand what affects the result.

Automate repeated work

Use the API when the same calculation needs to run inside your product or workflow.

FAQ

How do I use this capability?

Complete the fields above and run it on this page. The form highlights anything that needs attention.

For developers — API access

Everything on this page is available programmatically. This section is for teams who want to wire it into their own systems; everyone else can just use the tool above.

API endpoint

POSThttps://api.kit.forhosting.com/enc/trithemius

Prefer to automate it? One authenticated POST creates the task; the result comes back by webhook or a signed link. The same capability also runs here on the web, by email and from Telegram — and soon from our app too.

Call it from your stack

curl -X POST https://api.kit.forhosting.com/enc/trithemius \
  -H "Authorization: Bearer $KIT_KEY" \
  -H "Content-Type: application/json" \
  -d '{"text":"Hello World"}'

const res = await fetch("https://api.kit.forhosting.com/enc/trithemius", {
  method: "POST",
  headers: {
    "Authorization": `Bearer ${process.env.KIT_KEY}`,
    "Content-Type": "application/json"
  },
  body: JSON.stringify({
    "text": "Hello World"
  })
});
const { task_id } = await res.json();

import os, requests

res = requests.post(
    "https://api.kit.forhosting.com/enc/trithemius",
    headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
    json={
    "text": "Hello World"
},
)
task_id = res.json()["task_id"]

<?php
$res = file_get_contents("https://api.kit.forhosting.com/enc/trithemius", false, stream_context_create([
  "http" => [
    "method"  => "POST",
    "header"  => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
    "content" => '{"text":"Hello World"}',
  ],
]));
$task = json_decode($res, true);

body := bytes.NewBufferString(`{"text":"Hello World"}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/enc/trithemius", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)

Example request

{
  "text": "Hello World"
}

Example response

{
  "task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
  "type": "enc.trithemius",
  "status": "queued",
  "_links": {
    "result": "/tasks/tsk_…/result"
  }
}

The API is asynchronous: the call returns a task_id immediately and the result arrives by webhook. Polling is capped at 1 req/s per task.

Pricing

Per request$0.002

Published price — no tokens, no invented credits. A failed task is never charged.

Errors

HTTP	Code	Meaning
`401`	`unauthorized`	Missing or invalid API key.
`402`	`insufficient_balance`	Your balance doesn't cover the task price.
`404`	`unknown_type`	That task type doesn't exist.
`429`	`rate_limited`	Too many requests. Use the webhook instead of polling.

Read the full KIT documentation →

Run — free