Implementing custom crypto algorithms is not secure CS-S1005
Security
Critical
a02
cwe-200
cwe-319
owasp top 10
Certain classes in System.Security.Cryptography serve as the base for further implementation of crypto algorithms. However, it is recommended that you do not write your own implementation and use the standard and secure ones already available in .NET.
Bad Practice
class Algo : HashAlgorithm
{
// ...
}
Recommended
using (var sha512 = SHA512.Create())
{
// ...
}