Runs entirely in your browser - no upload, no sign-up.
Shamir secret sharing divides a secret into multiple independent shares and sets a threshold for recovery. In a 3-of-5 setup, any three shares rebuild the original text, while one or two cannot reconstruct its content. This tool creates and combines shares locally in your browser.
Type or paste up to 64 KiB of text. Use the visibility control if you need to check it.
Set the total number of shares and how many different shares recovery should require.
Copy or download the generated strings, then store each share in a genuinely separate place.
Switch to recovery, paste any threshold-sized subset with one share per line, and confirm the original text returns exactly.
The tool encodes your UTF-8 text with a checksum, then evaluates a fresh random polynomial for every byte in the finite field GF(256). Each share carries its set ID and threshold settings so mixed sets are rejected. No account is needed, and the tool does not upload your input.
This page uses a documented CanDoYa share format rather than a cryptocurrency wallet standard. It is suitable for general text secrets, but it does not create SLIP-0039 mnemonic shares.
No. Splitting and recovery run inside your browser, and this tool does not send the secret or shares to a server. For highly sensitive material, use a trusted device, load the page first, disconnect from the network, and close the tab after you verify recovery.
Yes. You can create and recover threshold shares without an account, payment, or usage meter. The tool supports text secrets up to 64 KiB and creates between 2 and 10 shares in one set.
You can create 2 to 10 shares and require any number from 2 through the total. A 2-of-3 setup favors simple recovery, while 3-of-5 adds more distribution and still tolerates two missing shares.
No. With fresh, uniformly random polynomial coefficients, fewer than the required number of shares cannot reconstruct the secret content. Share strings do expose metadata such as the payload length. Duplicate copies of one share do not help because recovery needs different share indexes.
The tool rejects shares with different set identifiers or settings. It also checks the reconstructed text with a checksum, which catches accidental edits in normal use. The checksum is not a digital signature and does not protect against deliberate forgery.
No. The cdy-shamir-v1 format is designed for text handled by this tool and is not SLIP-0039. Do not import these strings into a hardware wallet. Keep the complete share strings and access to this tool for later recovery.
Choose the smallest threshold that prevents one person or location from becoming a single point of failure, then make enough total shares to survive realistic loss. A 3-of-5 setup is a practical starting point, but the right choice depends on who stores each share.
