Digital Signatures
A digital signature is a method in which a unique code is attached to an electronic message. This unique code acts as a signature. It helps to verify a document's integrity and the sender's identity.
Steps for Creating a Digital Signature
- Create a hash of the message. A hash is also known as a message digest.
- Encrypt the hash (from Step 1) with the private key of the sender.
The following figure explains the process in detail:
Figure 8.14: Digital signature
What is a Hash or a Message Digest?
A hash value is a value derived from a message using a mathematical algorithm. A hash value is unique for each message. If a message changes, its hash value also changes.
The following figure further illustrates this:
Figure 8.15: Hash value
The following is a screenshot of software showing a hash value of the message Meeting at 8 AM:
Figure 8.16: Hash software
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