SHA-256 (Secure Hash Algorithm 256-bit) is a cryptographic hash function that produces a 256-bit (32-byte) hash value. It is widely used for security applications and data integrity verification. In the context of macOS, SHA-256 can be used for verifying file integrity, securing passwords, and ensuring data authenticity. This article will guide you through the process of generating SHA-256 hashes using the Terminal in macOS.

Examples:

1. Generating SHA-256 Hash for a File: To generate a SHA-256 hash for a file in macOS, you can use the shasum command in the Terminal. Here’s how to do it:

   shasum -a 256 /path/to/your/file

   Replace /path/to/your/file with the actual path to the file you want to hash. For example:

   shasum -a 256 ~/Documents/example.txt

   This command will output the SHA-256 hash of the specified file.

2. Generating SHA-256 Hash for a String: If you need to generate a SHA-256 hash for a string, you can use the echo command combined with shasum. Here’s an example:

   echo -n "your_string_here" | shasum -a 256

   The -n flag with echo ensures that no newline character is added to the string. For instance:

   echo -n "HelloWorld" | shasum -a 256

   This will output the SHA-256 hash of the string "HelloWorld".

3. Verifying File Integrity: To verify the integrity of a file, you can compare its SHA-256 hash with a known hash value. First, generate the hash of the file as shown above. Then, compare it with the expected hash value.

   expected_hash="your_expected_hash_here"
   file_hash=$(shasum -a 256 /path/to/your/file | awk '{ print $1 }')
   
   if [ "$file_hash" == "$expected_hash" ]; then
      echo "File integrity verified."
   else
      echo "File integrity verification failed."
   fi

   Replace your_expected_hash_here with the known hash value and /path/to/your/file with the actual file path.