模型中双向加密属性的Getter / setter

Question

I have a need to encrypt certain fields in the database, so, I need to encrypt the data going into the database, and then decrypt it when displaying it. I've already got my encryption methods and decryption methods set up and I had it working like this in, for example, an action:

model.EncryptedProperty = Encrypt(viewModel.Property);
viewModel.Property = Decrypt(EncryptedProperty);

That's fine, but my problem with it is that other developers will need to remember to encrypt/decrypt a property any time they use the property. This can be a problem for someone new on the project as it requires them to know about this property being encrypted before hand. I sought to improve the encryption by encrypting/decrypting on the model like so:

private string _property;
public string Property
{
    get { return DecryptString(_property); }
    set { _property = EncryptString(value); }
}

However, this doesn't seem to work, when I view this property in the view, it looks as if though it has encrypted the encrypted data in the database (I have tested this by using DecryptString(DecriptString(_property)) which returns the true value.

What is the solution here? Is there a more elegant way to approach this?

Answer 1

In that scenario, I might do something like:

[WhateverYourDataLayerNeeds("Property")]
public string EncryptedProperty {get;set;}

public string DecryptedProperty
{
    get { return DecryptString(EncryptedProperty); }
    set { EncryptedProperty = EncryptString(value); }
}

Then the database layer only talks to the first, and there is no confusion.

Answer 2

Marc Gravell's answer is definitely the answer matching the question, but if anyone is coming from an Entity Framework code first approach, this is what I ended up doing to obfuscate the encrypted property from any other developers:

public class Model 
{
    // Other properties

    private string EncryptedProperty { get; set; }
    [NotMapped]
    public string Property
    {
        get { return Decrypt(EncryptedProperty); }
        return { EncryptedProperty = Encrypt(value); }
    }

    public class ModelConfiguration : EntityTypeConfiguration<Model>
    {
        public ModelConfiguration() 
        {
            Property(p => p.EncryptedProperty);
        }
    }
}

Then in my ApplicationDbContext

protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
     modelBuilder.Configurations.Add(new Model.ModelConfiguration);
}