DataProtector Класс

Определение

Предоставляет базовый класс для предохранителей данных.Provides the base class for data protectors.

public ref class DataProtector abstract
public abstract class DataProtector
type DataProtector = class
Public MustInherit Class DataProtector
Наследование
DataProtector
Производный

Примеры

В следующем примере показано, как создать средство защиты данных, использующее класс защиты с параметром для дополнительной энтропии.The following example demonstrates how to create a data protector that uses a protection class with an option for extra entropy. По умолчанию DataProtector класс добавляет хэш свойств цели в зашифрованные данные.By default, the DataProtector class prepends the hash of the purpose properties to the data to be encrypted. Эту функцию можно отключить и использовать хэшированное назначение как лишнюю энтропию при вызове средства защиты данных с дополнительным параметром энтропии.You can turn that functionality off and use the hashed purpose as extra entropy when calling a data protector with an extra entropy option.

using System;
using System.Security.Permissions;

namespace System.Security.Cryptography
{
    public sealed class MyDataProtector : DataProtector
    {
        public DataProtectionScope Scope { get; set; }
        // This implementation gets the HashedPurpose from the base class and passes it as OptionalEntropy to ProtectedData.
        // The default for DataProtector is to prepend the hash to the plain text, but because we are using the hash
        // as OptionalEntropy there is no need to prepend it.
        protected override bool PrependHashedPurposeToPlaintext
        {
            get
            {
                return false;
            }
        }
        // To allow a service to hand out instances of a DataProtector we demand unrestricted DataProtectionPermission
        // in the constructor, but Assert the permission when ProviderProtect is called.  This is similar to FileStream
        // where access is checked at time of creation, not time of use.
        [SecuritySafeCritical]
        [DataProtectionPermission(SecurityAction.Assert, ProtectData = true)]
        protected override byte[] ProviderProtect(byte[] userData)
        {
            // Delegate to ProtectedData
            return ProtectedData.Protect(userData, GetHashedPurpose(), Scope);
        }
        // To allow a service to hand out instances of a DataProtector we demand unrestricted DataProtectionPermission
        // in the constructor, but Assert the permission when ProviderUnProtect is called.  This is similar to FileStream
        // where access is checked at time of creation, not time of use.
        [SecuritySafeCritical]
        [DataProtectionPermission(SecurityAction.Assert, UnprotectData = true)]
        protected override byte[] ProviderUnprotect(byte[] encryptedData)
        {
            // Delegate to ProtectedData
            return ProtectedData.Unprotect(encryptedData, GetHashedPurpose(), Scope);
        }
        public override bool IsReprotectRequired(byte[] encryptedData)
        {
            // For now, this cannot be determined, so always return true;
            return true;
        }
        // Public constructor
        // The Demand for DataProtectionPermission is in the constructor because we Assert this permission
        // in the ProviderProtect/ProviderUnprotect methods.
        [DataProtectionPermission(SecurityAction.Demand, Unrestricted = true)]
        [SecuritySafeCritical]
        public MyDataProtector(string appName, string primaryPurpose, params string[] specificPurpose)
            : base(appName, primaryPurpose, specificPurpose)
        {
        }
    }
}
Imports System.Security
Imports System.Security.Cryptography
Imports System.Security.Permissions



Public NotInheritable Class MyDataProtector
    Inherits DataProtector

    Public Property Scope() As DataProtectionScope
        Get
            Return Scope
        End Get
        Set(value As DataProtectionScope)
        End Set
    End Property ' This implementation gets the HashedPurpose from the base class and passes it as OptionalEntropy to ProtectedData.
    ' The default for DataProtector is to prepend the hash to the plain text, but because we are using the hash 
    ' as OptionalEntropy there is no need to prepend it.

    Protected Overrides ReadOnly Property PrependHashedPurposeToPlaintext() As Boolean
        Get
            Return False
        End Get
    End Property

    ' To allow a service to hand out instances of a DataProtector we demand unrestricted DataProtectionPermission 
    ' in the constructor, but Assert the permission when ProviderProtect is called.  This is similar to FileStream
    ' where access is checked at time of creation, not time of use.
    <SecuritySafeCritical(), DataProtectionPermission(SecurityAction.Assert, ProtectData:=True)> _
    Protected Overrides Function ProviderProtect(ByVal userData() As Byte) As Byte()
        ' Delegate to ProtectedData
        Return ProtectedData.Protect(userData, GetHashedPurpose(), Scope)

    End Function 'ProviderProtect

    ' To allow a service to hand out instances of a DataProtector we demand unrestricted DataProtectionPermission 
    ' in the constructor, but Assert the permission when ProviderUnProtect is called.  This is similar to FileStream
    ' where access is checked at time of creation, not time of use.
    <SecuritySafeCritical(), DataProtectionPermission(SecurityAction.Assert, UnprotectData:=True)> _
    Protected Overrides Function ProviderUnprotect(ByVal encryptedData() As Byte) As Byte()
        ' Delegate to ProtectedData
        Return ProtectedData.Unprotect(encryptedData, GetHashedPurpose(), Scope)

    End Function 'ProviderUnprotect

    Public Overrides Function IsReprotectRequired(ByVal encryptedData() As Byte) As Boolean
        ' For now, this cannot be determined, so always return true;
        Return True

    End Function 'IsReprotectRequired

    ' Public constructor
    ' The Demand for DataProtectionPermission is in the constructor because we Assert this permission 
    ' in the ProviderProtect/ProviderUnprotect methods. 
    <DataProtectionPermission(SecurityAction.Demand, Unrestricted:=True), SecuritySafeCritical()> _
    Public Sub New(ByVal appName As String, ByVal primaryPurpose As String, ParamArray specificPurpose() As String)
        MyBase.New(appName, primaryPurpose, specificPurpose)

    End Sub
End Class

В следующем примере показан простой компонент защиты данных, использующий PrependHashedPurposeToPlaintext функциональные возможности DataProtector класса.The following example demonstrates a simple data protector that uses the PrependHashedPurposeToPlaintext functionality of the DataProtector class.

using System;
using System.Security.Permissions;

namespace System.Security.Cryptography
{
    public sealed class MemoryProtector : DataProtector
    {
        public MemoryProtectionScope Scope { get; set; }
        protected override bool PrependHashedPurposeToPlaintext
        {
            get
            {
                // Signal the DataProtector to prepend the hash of the purpose to the data.
                return true;
            }
        }
        // To allow a service to hand out instances of a DataProtector we demand unrestricted DataProtectionPermission
        // in the constructor, but Assert the permission when ProviderProtect is called.  This is similar to FileStream
        // where access is checked at time of creation, not time of use.
        [SecuritySafeCritical]
        [DataProtectionPermission(SecurityAction.Assert, ProtectData = true)]
        protected override byte[] ProviderProtect(byte[] userData)
        {

            // Delegate to ProtectedData
            ProtectedMemory.Protect(userData, Scope);
            return userData;
        }
        // To allow a service to hand out instances of a DataProtector we demand unrestricted DataProtectionPermission
        // in the constructor, but Assert the permission when ProviderUnprotect is called..  This is similar to FileStream
        // where access is checked at time of creation, not time of use.
        [SecuritySafeCritical]
        [DataProtectionPermission(SecurityAction.Assert, UnprotectData = true)]
        protected override byte[] ProviderUnprotect(byte[] encryptedData)
        {

            ProtectedMemory.Unprotect(encryptedData,Scope);
                return encryptedData;
        }

        public override bool IsReprotectRequired(byte[] encryptedData)
        {
            // For now, this cannot be determined so always return true.
            return true;
        }
        // Public constructor
        // The Demand for DataProtectionPermission is in the constructor because we Assert this permission
        // in the ProviderProtect/ProviderUnprotect methods.
        [DataProtectionPermission(SecurityAction.Demand, Unrestricted = true)]
        [SecuritySafeCritical]
        public MemoryProtector(string appName, string primaryPurpose, params string[] specificPurpose)
            : base(appName, primaryPurpose, specificPurpose)
        {
        }
    }
}
Imports System.Security
Imports System.Security.Permissions
Imports System.Security.Cryptography



Public NotInheritable Class MemoryProtector
    Inherits DataProtector

    Public Property Scope() As MemoryProtectionScope
        Get
            Return Scope
        End Get
        Set(value As MemoryProtectionScope)
        End Set
    End Property

    Protected Overrides ReadOnly Property PrependHashedPurposeToPlaintext() As Boolean
        Get
            ' Signal the DataProtector to prepend the hash of the purpose to the data.
            Return True
        End Get
    End Property

    ' To allow a service to hand out instances of a DataProtector we demand unrestricted DataProtectionPermission 
    ' in the constructor, but Assert the permission when ProviderProtect is called.  This is similar to FileStream
    ' where access is checked at time of creation, not time of use.
    <SecuritySafeCritical(), DataProtectionPermission(SecurityAction.Assert, ProtectData:=True)> _
    Protected Overrides Function ProviderProtect(ByVal userData() As Byte) As Byte()

        ' Delegate to ProtectedData
        ProtectedMemory.Protect(userData, Scope)
        Return userData

    End Function 'ProviderProtect

    ' To allow a service to hand out instances of a DataProtector we demand unrestricted DataProtectionPermission 
    ' in the constructor, but Assert the permission when ProviderUnprotect is called..  This is similar to FileStream
    ' where access is checked at time of creation, not time of use.
    <SecuritySafeCritical(), DataProtectionPermission(SecurityAction.Assert, UnprotectData:=True)> _
    Protected Overrides Function ProviderUnprotect(ByVal encryptedData() As Byte) As Byte()

        ProtectedMemory.Unprotect(encryptedData, Scope)
        Return encryptedData

    End Function 'ProviderUnprotect

    Public Overrides Function IsReprotectRequired(ByVal encryptedData() As Byte) As Boolean
        ' For now, this cannot be determined so always return true.
        Return True

    End Function 'IsReprotectRequired

    ' Public constructor
    ' The Demand for DataProtectionPermission is in the constructor because we Assert this permission 
    ' in the ProviderProtect/ProviderUnprotect methods. 
    <DataProtectionPermission(SecurityAction.Demand, Unrestricted:=True), SecuritySafeCritical()> _
    Public Sub New(ByVal appName As String, ByVal primaryPurpose As String, ParamArray specificPurpose() As String)
        MyBase.New(appName, primaryPurpose, specificPurpose)

    End Sub
End Class

Комментарии

Этот класс защищает хранимые данные от просмотра и изменения.This class protects stored data from viewing and tampering. Доступ к защищенным данным получается путем создания экземпляра этого класса и использования строк точного назначения, которые использовались для защиты данных.The access to the protected data is obtained by creating an instance of this class and using the exact purpose strings that were used to protect the data. Вызывающему объекту не требуется ключ для защиты или снятия защиты данных.The caller does not need a key to either protect or unprotect the data. Ключ предоставляется алгоритмом шифрования.The key is provided by the encryption algorithm.

Производные классы должны переопределять ProviderProtect Unprotect методы и, которые DataProtector базовый класс вызывает обратно.Derived classes must override the ProviderProtect and Unprotect methods, which the DataProtector base class calls back into. Они также должны переопределять IsReprotectRequired метод, который всегда может возвращать true небольшую вероятность потери эффективности, когда приложения обновляют свою базу данных сохраненного зашифрованного текста.They must also override the IsReprotectRequired method, which can always return true with a potential small loss of efficiency when applications refresh their database of stored cipher text. Производные классы должны предоставлять конструктор, который вызывает конструктор базового класса, который задает ApplicationName свойства, SpecificPurposes и PrimaryPurpose .Derived classes should provide a constructor that calls the base class constructor, which sets the ApplicationName, SpecificPurposes, and PrimaryPurpose properties.

Конструкторы

DataProtector(String, String, String[])

Создает новый экземпляр класса DataProtector, используя предоставленное имя приложения, первичную цель и определенные цели.Creates a new instance of the DataProtector class by using the provided application name, primary purpose, and specific purposes.

Свойства

ApplicationName

Возвращает имя приложения.Gets the name of the application.

PrependHashedPurposeToPlaintext

Определяет, добавляется ли хэш в начало массива текста перед шифрованием.Specifies whether the hash is prepended to the text array before encryption.

PrimaryPurpose

Получает основное назначение для защищенных данных.Gets the primary purpose for the protected data.

SpecificPurposes

Получает определенное назначение для защищенных данных.Gets the specific purposes for the protected data.

Методы

Create(String, String, String, String[])

Создает экземпляр реализации предохранителя данных с помощью указанного имени класса предохранителя данных, имени приложения, первичной цели и определенных целей.Creates an instance of a data protector implementation by using the specified class name of the data protector, the application name, the primary purpose, and the specific purposes.

Equals(Object)

Определяет, равен ли указанный объект текущему объекту.Determines whether the specified object is equal to the current object.

(Унаследовано от Object)
GetHashCode()

Служит хэш-функцией по умолчанию.Serves as the default hash function.

(Унаследовано от Object)
GetHashedPurpose()

Создает хэш значений свойств, определяемых конструктором.Creates a hash of the property values specified by the constructor.

GetType()

Возвращает объект Type для текущего экземпляра.Gets the Type of the current instance.

(Унаследовано от Object)
IsReprotectRequired(Byte[])

Указывает, необходимо ли перешифрование для указанных зашифрованных данных.Determines if re-encryption is required for the specified encrypted data.

MemberwiseClone()

Создает неполную копию текущего объекта Object.Creates a shallow copy of the current Object.

(Унаследовано от Object)
Protect(Byte[])

Защищает заданные пользовательские данные.Protects the specified user data.

ProviderProtect(Byte[])

Задает метод делегата в производном классе, в адрес которого метод Protect(Byte[]) в базовом классе выполняет обратный вызов.Specifies the delegate method in the derived class that the Protect(Byte[]) method in the base class calls back into.

ProviderUnprotect(Byte[])

Задает метод делегата в производном классе, в адрес которого метод Unprotect(Byte[]) в базовом классе выполняет обратный вызов.Specifies the delegate method in the derived class that the Unprotect(Byte[]) method in the base class calls back into.

ToString()

Возвращает строку, представляющую текущий объект.Returns a string that represents the current object.

(Унаследовано от Object)
Unprotect(Byte[])

Снимает защиту с указанных защищенных данных.Unprotects the specified protected data.

Применяется к