TOOL 004 / POST-QUANTUM ENGINEERING · BETA
LuniQ Fit
Will your messages still fit after you switch to post-quantum crypto?
A post-quantum signature is 10–100× larger than ECDSA. Pick your link — MIL-STD-1553, CAN, LoRaWAN, Bluetooth LE, UDP, QR or TLS — and see bytes, fragments, bus time and airtime for ML-DSA, SLH-DSA, ML-KEM and Falcon next to today’s algorithms. Runs entirely in your browser.
01 / YOUR LINK
Where do the bytes travel?
02 / WHAT YOU SEND
What does the crypto add?
03 / RESULT
Fit on your link
| Algorithm | Standard | Crypto bytes | Bytes sent | Frames | Time | vs classical |
|---|
Suggestions
04 / TLS 1.3 HANDSHAKE
Does the server’s first flight still fit?
Bigger keys and certificates can push the server’s first reply past TCP’s initial congestion window (an extra round trip) or past QUIC’s anti-amplification limit (the server must wait).
Planning estimates, not a substitute for prototyping and timing analysis on your system. Settings are kept only in this browser; “Reset” deletes them.
METHOD & SOURCES
How the numbers are made
Sizes. ML-KEM (FIPS 203), ML-DSA (FIPS 204) and SLH-DSA (FIPS 205) sizes are exact. They were measured from a real implementation and checked against the FIPS parameter formulas. Falcon / FN-DSA is shown for planning only: FIPS 206 had not been published at the time of writing. Its signatures vary in length; we use the padded maximum (666 / 1280 bytes).
MIL-STD-1553B. Up to 32 sixteen-bit data words per message at 1 Mbps (20 µs per word). Time includes the command word, data words, a 12 µs maximum RT response, the status word and a 4 µs gap. Uses only publicly released MIL-STD-1553B parameters; no program-specific data.
CAN. Classic CAN carries 8 bytes per frame (111 bits nominal, 135 with worst-case bit stuffing, 11-bit IDs). Messages above 7 bytes use ISO-TP (ISO 15765-2): 6 data bytes in the first frame and 7 in each consecutive frame. CAN FD uses 64-byte frames with ISO-TP FD; its frame time is approximate.
LoRaWAN. Maximum application payload per data rate from the LoRaWAN Regional Parameters (US915, EU868), plus 13 bytes of LoRaWAN overhead. Airtime uses Semtech’s LoRa time-on-air formula (explicit header, CRC, coding rate 4/5, 8-symbol preamble). The Things Network’s fair-use limit is 30 s of uplink airtime per device per day; EU868 sub-bands allow 1% duty cycle.
Internet. 1232-byte UDP payloads stay inside the IPv6 minimum MTU of 1280 bytes; 1472 bytes fills a 1500-byte Ethernet frame over IPv4. TLS uses a 10 × 1460-byte initial TCP window (RFC 6928) and QUIC’s rule that a server may send at most 3× what it received before address validation (RFC 9000), with client Initials of at least 1200 bytes. Certificate field sizes are an editable estimate.
QR. Version 40 byte-mode capacity per error-correction level (ISO/IEC 18004).