Check a signature before trusting a message.
One exchange at a time. Read what changes, then explain it in your own words before moving on.
Read the full lesson- Meet the components
- Follow the steps
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Interactive example
Verification succeeds
The verifier needs an authentic public key associated with the intended signer.
How to use this example
Select Next step to read at your own pace, or Animate step to watch one exchange. Nothing advances until you choose.
What it means
Everyday example
State in this scenario
Inspect components & read every step
- You
The person making the decision in this fictional example.
Example: You decide whether to share information, approve a request or check it first.
- Check or transform
Digital-signature verification using the message, signature and an authentic public key.
Example: Check a signed release without assuming a valid signature makes the software harmless.
- Result
The outcome produced by the operation in this example.
Example: Read the current state and the step explanation to see what succeeded or failed.
Verification succeeds
The verifier needs an authentic public key associated with the intended signer.
- You Check or transform: Message and signature. The verifier receives the release and its digital signature and uses the trusted public key.
- Check or transform Result: Signature verifies. Verification succeeds for these bytes and this key. The signature alone does not prove the content is safe or true.
Message altered
Changing signed content causes verification to fail in this example.
- You Check or transform: Changed message. The verifier receives modified bytes alongside the original signature.
- Check or transform Result: Verification fails. The signature does not verify against the modified message. Stop and investigate the source.
Fictional teaching trace. One moving dot represents an exchange, not a measured network capture.