Implementations.md

sidebar_position	5
sidebar_label	ICrypto implementations

⚠️ Deprecation Warning ⚠️

This library has been deprecated and will no longer receive updates.

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ICrypto implementations

SymmetricCrypto class

RockLib.Encryption provides an implementation of ICrypto, SymmetricCrypto, that uses the various symmetric encryption implementations that are provided by .NET. The supported algorithms are: AES, DES, RC2, Rijndael, and Triple DES. This class has public constructors and can be instantiated directly.

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To register a SymmetricCrypto with the Microsoft.Extensions.DependencyInjection container, use the AddSymmetricCrypto extension method, and add credentials with the AddCredential method:

public void ConfigureServices(IServiceCollection services)
{
    services.AddSymmetricCrypto()
        .AddCredential("CQSImVlbvJMZcnrkzT3/ouW1klt6STljrDjRiBzIsSk=", SymmetricAlgorithm.Rijndael) // This is the default (unnamed) credential.
        .AddCredential("MyDESCredential", "2LQliivTtNo=", SymmetricAlgorithm.DES, 8); // This credential is named "MyDESCredential".
}

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If using the default value for the static Crypto class, it can be configured as follows:

appsettings.json

{
  "rocklib.encryption": {
    "type": "RockLib.Encryption.Symmetric.SymmetricCrypto, RockLib.Encryption",
    "value": {
      "credentials": [
        {
          "name": "default",
          "algorithm": "Rijndael",
          "ivsize": 16,
          "key": "bo3Vtyg4uBhcKgQKQ6H9LmeYXF+7BG42XMoS7AgZFz4="
        },
        {
          "name": "triple_des",
          "algorithm": "TripleDES",
          "ivsize": 8,
          "key": "bNYqGfSV6xqgoucDMqwGWFRZ8KHFXe+m"
        }
      ]
    }
  }
}

app.config/web.config

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
  <configSections>
    <section name="rocklib.encryption" type="RockLib.Configuration.RockLibConfigurationSection, RockLib.Configuration" />
  </configSections>

  <rocklib.encryption>
    <crypto type="RockLib.Encryption.Symmetric.SymmetricCrypto, RockLib.Encryption">
      <value>
        <encryptionSettings>
          <credentials name="default"
                       algorithm="Rijndael"
                       ivsize="16"
                       key="bo3Vtyg4uBhcKgQKQ6H9LmeYXF+7BG42XMoS7AgZFz4=" />
          <credentials name="triple_des"
                       algorithm="TripleDES"
                       ivsize="8"
                       key="bNYqGfSV6xqgoucDMqwGWFRZ8KHFXe+m" />
        </encryptionSettings>
      </value>
    </crypto>
  </rocklib.encryption>
</configuration>

Note that it is a bad idea to store symmetric keys in configuration plaintext as shown above.

CompositeCrypto class

If your application needs to support more than one implementation of the ICrypto interface, you can use the CompositeCrypto class. It does so by implementing the composite pattern. The constructor of this class takes a collection of ICrypto objects. Each method of the CompositeCrypto class is implemented by iterating through that collection. The first item in the collection that returns true from its CanEncrypt or CanDecrypt method is the ICrypto that is used for the current encryption operation.