Suppose Merkle hash tree is used to authenticate eight messages, m1, m2, …, m8.

Question

Suppose Merkle hash tree is used to authenticate eight messages, m1, m2, …, m8. The eight messages are used to build the Merkle tree, and the root of the tree is signed with a digital signature s. i) To authenticate m3, besides m3 itself and the signature s of the tree root, which elements should be included in the message? How can the receiver verify the integrity of m3? ii) To authenticate m8, besides m8 itself and the signature s of the tree root, which elements should be included in the message? How can the receiver verify the integrity of m8?

Explanation / Answer

-Digital Signature is technique by which authenticity of a document can be verified.

-It also used to check genuineness of the document.

-A hash function is used for the process.

- It will check whether the document is tampered in digital field.

-It will provide origin identity and status of an electronic document transaction.

- For messages hash can be created by anyone.

-It will prevent the modification of the message or document.

- The sender has a private key, and the receiver has a verification key; the verification key allows the receiver to validate messages

-for verifying the document the receiver check document with receiver key and authenticate.

i) To authenticate m3, besides m3 itself and the signature s of the tree root, which elements should be included in the message? How can the receiver verify the integrity of m3?

ii) To authenticate m8, besides m8 itself and the signature s of the tree root, which elements should be included in the message? How can the receiver verify the integrity of m8?

So coming to your questions

Suppose we want to send data from source to destination.

-The document is applied with hash function which gives a number sequence called hash.

-This hash is then encrypted with sender Private Key.

Now the document is digitally signed.

The document is sent to the destination.

In receiver Signed Document, in order to check for authenticity of that following things to be carried out

-In destination it will apply hash function to the message.

-Then in destination it decrypts the signed document using Sender Public Key and gets a net hash .

-Then both hash values will compared.

-If difference is found it means the document is tampered.

-If no difference it is secured and not tampered.

This is how digital signatures are verifies and ensure the integrity.

I hope I answered your question .

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