Isaca Certification CISA Exam Dumps

 A digital signature is a cryptographic technique that verifies the authenticity and integrity of a message or document, by using a hash function and an asymmetric encryption algorithm. A hash function is a mathematical function that transforms any input data into a fixed-length output value called a digest, which is unique for each input. An asymmetric encryption algorithm uses two keys: a public key and a private key. The public key can be shared with anyone, while the private key must be kept secret by the owner. To create a digital signature, the sender first applies a hash function to the plaintext message togenerate a digest. Then, the sender encrypts the digest with their private key to produce the digital signature. To verify the digital signature, the receiver decrypts the digital signature with the sender’s public key to obtain the digest. Then, the receiver applies the same hash function to the plaintext message to generate another digest. If the two digests match, it means that the message has not been altered and that it came from the sender. The security of a digital signature depends on the secrecy of the sender’s private key. If an attacker obtains the sender’s private key, they can create fake digital signatures for any message they want, thus compromising the control provided by the digital signature. Reversing the hash function using the digest is not possible, as hash functions are designed to be one-way functions that cannot be inverted. Altering the plaintext message will result in a different digest after applying the hash function, which will not match with the decrypted digest from the digital signature, thus invalidating the digital signature. Deciphering the receiver’s public key is not relevant, as public keys are meant to be publicly available and do not affect the security of digital signatures. 

 The most significant risk associated with a new health records system that replaces a legacy system is data not being converted correctly, resulting in inaccurate patient records. Data conversion is the process of transferring data from one format or system to another. Data conversion is a critical step in implementing a new health records system, as it ensures that the patient data are consistent, complete, accurate, and accessible in the new system. Data not being converted correctly may cause errors, discrepancies, or losses in patient records, which may have serious implications for patient safety, quality of care, legal compliance, and privacy protection. Staff not being involved in the procurement process, creating user resistance to the new system; the deployment project experiencing significant overruns, exceeding budget projections; and the new system having capacity issues, leading to slow response times for users are also risks associated with a new health records system implementation, but they are not as significant as data not being converted correctly. References: [ISACA CISA Review Manual 27th Edition], page 281.

 Restricting program functionality according to user security profiles is the best control for ensuring appropriate segregation of duties within an accounts payable department. An IS auditor should verify that the access rights and permissions of the accounts payable staff are based on their roles and responsibilities, and that they are not able to perform incompatible or conflicting functions such as creating, approving, or paying invoices. This will help to prevent fraud, errors, or abuse of authority within the accounts payable process. The other options are less effective controls for ensuring segregation of duties, as they may involve audit trails, access restrictions, or user identification. References:

CISA Review Manual (Digital Version), Chapter 6, Section 6.31

CISA Review Questions, Answers & Explanations Database,Question ID 223

 The chain of custody has not been documented is a finding that should be of greatest concern for an IS auditor reviewing a forensic analysis process of an organization that has suffered a cyber attack. The chain of custody is a record of who handled, accessed, or modified the evidence during a forensic investigation. Documenting the chain of custody is essential to preserve the integrity, authenticity, and admissibility of the evidence in a court of law. The other options are less concerning findings that may not affect the validity or reliability of the forensic analysis process. References:

CISAReview Manual (Digital Version), Chapter 7, Section 7.51

CISA Review Questions, Answers &Explanations Database, Question ID 220