Exam CISA topic 1 question 7 discussion

To preserve the integrity of a message, the message is passed through an algorithm called a cryptographic hash function. The function creates a compressed image of the message, called a digest. To check the integrity of a message, the receiver runs the cryptographic hash function again and compares the new digest with the previous one.====>Underline Integrity and digest which is an image If both are the same, the receiver is sure that the original message has not been changed. To ensure message integrity and message origin authentication, Message Authentication Code (MAC) is created using a combination of hash function and secret key. A sender sends the message and the MAC to a receiver over the insecure channel. The receiver separates the message from the MAC. He then makes a new MAC from the message and the secret key. Bob then compares the newly created MAC with the one received. If the two MACs match, the message is authentic and has not been modified by an adversary.

the only different between A and D is what value is generated after hashing of message. Normally, to check integrity, hash will be created by receiver using the same algorithm used by sender. The result of hashing will be numerical then we can compare with the original numerical generated by sender to ensure the integrity of the file. Then, I chose D

A hash ensures the integrity of a message; if the hash value differs from the expected one, it implies the message has been altered​​.

"binary image" is more specific to the context of the actual data being hashed.

To confirm integrity for a hashed message, the receiver should use: A. the same hashing algorithm as the sender's to create a binary image of the file. Using the same hashing algorithm as the sender ensures that the receiver performs the same hashing process on the received message or file. This allows the receiver to generate a binary image or hash value identical to the one initially created by the sender. By comparing the generated hash value with the original hash value shared by the sender, the receiver can confirm whether the message or file has remained intact and has not been tampered with during transmission.

A is wrong because you're not trying to create a binary image of the file (raw data essentially), you want to compute a hash so you can compare hashes between the computers to ensure that no data has been lost or changed, thus the answer is D.

A hash value is essentially a unique identifier for a set of data, like a digital fingerprint for files. When a file’s contents are processed through a cryptographic algorithm, it produces a hash value—a unique numerical value that represents the contents of the file. This value is not an image of the file but rather a fixed-size string of characters that may include numbers and letters. The hash value changes significantly if the contents of the file are altered in any way, making it a reliable method for verifying data integrity. So, the answer is D.

Answer: D

only D makes sense

A is the correct one

A is the correct answer here

A is the right answer

Doesnt need to be numerical, can be hexadecimal so abcdef is also included (Eg. md5). From this perspective answer is A, as its all same when binary represented

C. a different hashing algorithm from the sender's to create a binary image of the file. When verifying the integrity of a hashed message, the receiver should use a different hashing algorithm from the sender's to create a binary image of the file. This is done to ensure that the integrity check is valid and that the message has not been tampered with during transmission. Using the same hashing algorithm as the sender to create a numerical representation of the file is not sufficient to confirm integrity because the hash value could have been altered during transmission.

For me it's D

A should be the one

https://www.101computing.net/hashing-algorithms-for-integrity-validation/