The ieUnit daily receipts
Every day, ieUnit records which source delivered which price and what was calculated from it – digitally signed and chained without gaps. You do not have to take our word for it: check it yourself.
What a receipt proves
A daily receipt records, for each of the nine basket values, which source reported which price, by which rule the price used was derived – one source, the median of several sources or, if all failed, the last valid price – and which ieUnit value resulted. The check above confirms four things:
- Fingerprint – unaltered: a digital fingerprint (SHA-256) is calculated from every receipt. If even a single character changes, the fingerprint is completely different.
- Signature – authentic: ieunit.org digitally signs every receipt (Ed25519). Anyone can check the signature – only the holder of the private key can forge it.
- Chain – without gaps: every receipt contains the fingerprint of its predecessor. Altering an old receipt afterwards breaks every later link of the chain.
- Recalculation – correctly calculated: your browser recalculates ieUnit from the prices in the receipt – with the same formula we use.
The check runs entirely in your browser. Our server only delivers the data – the verdict is yours.
Keeping a receipt
If you use ieUnit for a contract, an invoice or as a fee yardstick, download the receipt of the reference date and keep it. With “Check your own receipt file” it can be checked again at any time, even years later. That proves: on this day, 1 ieUnit was worth this much.
What a receipt does not prove (yet)
- A receipt shows what the sources reported according to ieunit.org. Whether an exchange really reported that price can only be checked against its own price history – the times are in the receipt.
- In theory, the operator could rewrite and re-sign the entire chain. That becomes visible as soon as anyone has kept an older receipt: its fingerprint no longer matches. The plan is to additionally anchor each day's fingerprint in the Bitcoin blockchain (via the free OpenTimestamps service). That will rule this out as well.
- Receipts exist since their introduction in October 2026. Earlier values come from the backtest and have no daily receipts.
Check it yourself – even without this page
The easiest way is to ask an AI assistant that can fetch web pages and run code – such as Claude, ChatGPT, Gemini or Codex:
Check the latest ieUnit daily receipt at https://ieunit.org/api/v1/receipt.php: 1. Compute SHA-256 over the exact UTF-8 bytes of the "receipt" field and compare it with "fingerprint". 2. Verify the Ed25519 signature in "signature" with the public key from https://ieunit.org/api/v1/receipts.php. 3. Compare "prev_fingerprint" with the fingerprint of the predecessor in the chain. 4. Recalculate ieUnit from the prices in the receipt and compare it with "result".
Or by hand with two standard tools, curl and OpenSSL (version 3.0 or later):
curl -s "https://ieunit.org/api/v1/receipt.php?part=receipt" > receipt.txt curl -s "https://ieunit.org/api/v1/receipt.php?part=signature" | openssl base64 -d -A > signature.bin curl -s "https://ieunit.org/api/v1/receipt.php?part=key" > key.pem sha256sum receipt.txt openssl pkeyutl -verify -pubin -inkey key.pem -rawin -in receipt.txt -sigfile signature.bin
The receipt is authentic and unaltered if the fingerprint shown matches the fingerprint field at ieunit.org/api/v1/receipt.php and OpenSSL reports “Signature Verified Successfully”. For a specific day, append &date=YYYY-MM-DD to every address. On Windows the command is curl.exe, and certutil -hashfile receipt.txt SHA256 shows the fingerprint; on a Mac shasum -a 256 receipt.txt.
The endpoints are described in the API documentation.