Hash Class

.NET Framework (current version)

Other Versions

Provides evidence about the hash value for an assembly. This class cannot be inherited.

Namespace: System.Security.Policy
Assembly: mscorlib (in mscorlib.dll)

Inheritance Hierarchy

System::Object
System.Security.Policy::EvidenceBase
System.Security.Policy::Hash

Syntax

C++

[SerializableAttribute]
[ComVisibleAttribute(true)]
public ref class Hash sealed : EvidenceBase, ISerializable

Constructors

	Name	Description
	Hash(Assembly^)	Initializes a new instance of the Hash class.

Properties

	Name	Description
	MD5	Gets the MD5 hash value for the assembly.
	SHA1	Gets the SHA1 hash value for the assembly.
	SHA256	Gets the SHA256 hash value for the assembly.

Methods

	Name	Description
	Clone()	Creates a new object that is a copy of the current instance.(Overrides EvidenceBase::Clone().)
	CreateMD5(array<Byte>^)	Creates a Hash object that contains an MD5 hash value.
	CreateSHA1(array<Byte>^)	Creates a Hash object that contains a SHA1 hash value.
	CreateSHA256(array<Byte>^)	Creates a Hash object that contains a SHA256 hash value.
	Equals(Object^)	Determines whether the specified object is equal to the current object.(Inherited from Object.)
	GenerateHash(HashAlgorithm^)	Computes the hash value for the assembly using the specified hash algorithm.
	GetHashCode()	Serves as the default hash function. (Inherited from Object.)
	GetObjectData(SerializationInfo^, StreamingContext)	Gets the SerializationInfo object with the parameter name and additional exception information.
	GetType()	Gets the Type of the current instance.(Inherited from Object.)
	ToString()	Returns a string representation of the current Hash.(Overrides Object::ToString().)

A hash value represents a unique value that corresponds to a particular set of bytes. Rather than referring to an assembly by name, version, or other designation, a hash value designates the assembly without ambiguity. Names are subject to collisions in rare cases where the same name is given to completely different code. Different variations of code can accidentally be marked with the same version. However, even changing a single bit results in a very different hash value.

Hash values are a cryptographically secure way to refer to specific assemblies in policy without the use of digital signatures. A secure hash algorithm is designed so that it is computationally infeasible to construct a different assembly with the identical hash value by either an accidental or malicious attempt. By default, evidence from the SHA1 and MD5 hash algorithms is supported, although any hash algorithm can be used through GenerateHash.

Version Information

.NET Framework
Available since 1.1

Thread Safety

Any public static ( Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.