Cisco Cyber Security Practice Exam

Which hashing algorithm can produce hash values beyond 128 bits?

1. MD5

2. SHA

3. DES

4. RC4

The correct answer is: SHA

The choice of SHA as the hashing algorithm that can produce hash values beyond 128 bits is accurate as SHA (Secure Hash Algorithm) encompasses a range of algorithms with varying output lengths. Specifically, SHA-1 generates a 160-bit hash, SHA-256 produces a 256-bit hash, and SHA-512 creates a 512-bit hash. This variability allows SHA algorithms to be used in applications requiring higher security standards, as longer hash values generally provide increased resistance against collision attacks. In contrast, MD5 is limited to a 128-bit hash output, making it susceptible to vulnerabilities that can be exploited to produce identical hash outputs from different inputs. DES (Data Encryption Standard) is not a hashing algorithm; it is a symmetric-key block cipher used for encryption rather than hashing, which does not produce hash values at all. Similarly, RC4 is a stream cipher used for encryption and does not generate hash values, further distinguishing it from proper hashing algorithms like SHA. Thus, the choice of SHA is the most fitting, given its ability to produce hash values exceeding 128 bits.