Final answer:
The hashing algorithm that can be used to hash passwords in the etc shadow file is the MD5 algorithm. Therefore, the correct answer is option 1.
Step-by-step explanation:
The MD5 algorithm, which stands for Message Digest Algorithm 5, is a widely used cryptographic hash function that produces a 128-bit (16-byte) hash value. It is commonly utilized to verify data integrity. The MD5 algorithm works by taking an input (or 'message') and producing a fixed-size string of bytes that appears random. The output, known as the hash, is typically represented as a 32-character hexadecimal number.
Using a hash function like MD5 involves passing data through a hash algorithm to produce a unique string of characters that identify the contents of the file. If even a single character in the input is changed, the resulting hash will be entirely different. This is why MD5 and other hash functions are useful for things like checking file integrity and storing passwords securely. However, it's worth noting that MD5 is not collision-resistant and is vulnerable to hash collisions, making it unsuitable for security-sensitive applications in modern standards.