Generate a composite key from a list of fields

hashfunc.cs

public static string GetKeyFromRecord<T>(IEnumerable<string> pRecordProps) where T : HashAlgorithm, new() {
    using (T hashAlg = new T()) {
        IEnumerable<byte> result = pRecordProps
            .Select(x => hashAlg.ComputeHash(Encoding.UTF8.GetBytes(x ?? string.Empty)))
            .SelectMany(y => y);
        return Convert.ToBase64String(hashAlg.ComputeHash(result.ToArray()));
    }
}