XK0-005 · Question #322
A systems administrator has retrieved the latest copy of the system backup files, which had been stored offsite at a third-party vendor. The systems administrator wants to validate that the data was…
The correct answer is A. Perform a MD5 hash on the data. To verify data integrity and confirm that files have not been modified since a backup, comparing cryptographic hash values (like MD5 or SHA-256) of the current data against the hash values recorded at the time of backup is the most effective method.
Question
A systems administrator has retrieved the latest copy of the system backup files, which had been stored offsite at a third-party vendor. The systems administrator wants to validate that the data was not modified since the backup. Which of the following would BEST verify that the data remained the same?
Options
- APerform a MD5 hash on the data.
- BPerform a SCP from the backup.
- CPerform rsync.
- DRestore from the last full backup.
How the community answered
(23 responses)- A78% (18)
- B4% (1)
- C4% (1)
- D13% (3)
Why each option
To verify data integrity and confirm that files have not been modified since a backup, comparing cryptographic hash values (like MD5 or SHA-256) of the current data against the hash values recorded at the time of backup is the most effective method.
Performing an MD5 hash on the retrieved data and comparing it to a hash taken at the time of the original backup is the best way to verify data integrity. If the hashes match, it provides strong assurance that the data has not been altered during storage or transit.
SCP (Secure Copy Protocol) is used for securely transferring files, not for verifying their integrity after retrieval.
`rsync` is a utility for efficient file synchronization and transfer, which can compare files but is not primarily designed as a standalone integrity verification tool when hashes are specifically requested for comparison against a previous state.
Restoring from the last full backup would involve overwriting the current data and does not directly verify the integrity of the *retrieved backup files* themselves against a known good state.
Concept tested: Data integrity verification using hashing
Source: https://man7.org/linux/man-pages/man1/md5sum.1.html
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