LEAST Secure Hashing Algorithm

C.

The least secure hashing algorithm among the given options is MD5 (Option C).

A hashing algorithm is a cryptographic function that takes input data of arbitrary size and returns a fixed-size output, called a hash value or message digest. Hash functions are used to verify data integrity, to create digital signatures, and for password hashing.

MD5 (Message Digest 5) is a widely-used hashing algorithm that produces a 128-bit hash value. However, MD5 has been found to have several security weaknesses, making it vulnerable to various attacks, including collisions and pre-image attacks.

In a collision attack, an attacker tries to find two different inputs that produce the same hash value. In 2004, a team of Chinese cryptographers demonstrated a practical collision attack on MD5, which means that it is no longer considered secure for applications where collision resistance is required, such as digital signatures.

In a pre-image attack, an attacker tries to find an input that produces a given hash value. MD5 has also been found to be vulnerable to pre-image attacks, which means that an attacker can find a message that has the same hash value as a given message, without knowing the original message.

In contrast, SHA-1 (Secure Hash Algorithm 1) is a hashing algorithm that produces a 160-bit hash value and is more secure than MD5. However, it has also been found to have weaknesses, and it is recommended to use newer and more secure algorithms, such as SHA-256 and SHA-3.

RIPEMD (RACE Integrity Primitives Evaluation Message Digest) is a family of hashing algorithms developed by the European Union. It produces a variable-length hash value and is considered secure.

DES (Data Encryption Standard) is a symmetric key algorithm used for encryption, not hashing, and it is also considered insecure due to its small key size and other vulnerabilities.

In summary, the least secure hashing algorithm among the given options is MD5, due to its vulnerabilities to collisions and pre-image attacks.