Digital signing

12 random words (or your choice of unique text):
Copy
Message to sign/verify:
SignCopy
Status: 

Signing Instructions:

  1. A random set of 12 memorizable English words appears in the upper text box every time this page is refreshed.
  2. They should be securely stored and kept private because they are used to generate your secret key and therefore may be needed to prove that you are the owner of your public key.
  3. Type or paste text into the Message box.
  4. Use the Sign button to compute the signature from the secret key and the message.
  5. Send to the recipient the signed message including the appended public key and signature.
  6. Dragging and dropping a file into the Message box will automatically compute its SHA-256 checksum, base64 encoded, and sign it.
Verifying instructions:
  1. The secret key is not used for verification so it doesn't matter what is in the upper text box.
  2. Paste the received signed message into the Message box.
  3. If the message was signed by the owner of the public key and has not been altered since signing, the Status field will indicate verified and the Message box background will turn green; otherwise it turns pink.
Source code and security notes