Second pre-image resistance is another important property of cryptographic hash functions like SHA-256. It means that given:

1. A hash value (digest)

2. An input data (message)

it's computationally infeasible to find another input data (message) that produces the same hash value (digest).

In other words, it's impossible to find a different input data that results in the same hash value as the original input data. This property ensures that:

1. Data integrity is maintained: Even if an attacker tries to manipulate the data, they cannot find a different input data that produces the same hash value.

2. Digital signatures are secure: An attacker cannot find a different input data that produces the same hash value, making it impossible to forge a digital signature.

Second pre-image resistance is a stronger property than pre-image resistance, as it requires finding a different input data that produces the same hash value, rather than just recreating the original input data. This property makes hash functions like SHA-256 even more secure and reliable for various applications.