C# 7 and .NET Core: Modern Cross-Platform Development - Second Edition

Hashing data

There are multiple hash algorithms you can choose from in .NET Core. Some do not use any key, some use symmetric keys, and some use asymmetric keys.

There are two important factors to consider when choosing a hash algorithm:

• Collision resistance: How rare is it to find two inputs that share the same hash?
• Preimage resistance: For a hash, how difficult would it be to find another input that shares the same hash?

Here are some common hashing algorithms:

Algorithm	Hash size	Description
MD5	16 bytes	This is commonly used because it is fast, but it is not collision-resistant.
SHA1, SHA256, SHA384, SHA512	20 bytes, 32 bytes, 48 bytes, 64 bytes	These are Secure Hashing Algorithm 2nd generation algorithms (SHA2) with different hash ...