GAC: What is Delay signing In .Net Framework

Interview Questions:- 

During development process you will need strong name keys to be exposed to developer which is

not a good practice from security aspect point of view.In such situations you can assign the key
later on and during development you an use delay signing
Following is process to delay sign an assembly:

• First obtain your string name keys using SN.EXE.

• Annotate the source code for the assembly with two custom attributes from
System.Reflection: AssemblyKeyFileAttribute, which passes the name of the file
containing the public key as a parameter to its constructor.
AssemblyDelaySignAttribute, which indicates that delay signing, is being used by
passing true as a parameter to its constructor. For example as shown below:

[Assembly: AssemblyKeyFileAttribute ("myKey.snk")]
[Assembly: AssemblyDelaySignAttribute (true)]

The compiler inserts the public key into the assembly manifest and reserves space in the PE file
for the full strong name signature. The real public key must be stored while the assembly is built
so that other assemblies that reference this assembly can obtain the key to store in their own
assembly reference.

• Because the assembly does not have a valid strong name signature, the verification of
that signature must be turned off. You can do this by using the –Vr option with the
Strong Name tool. The following example turns off verification for an assembly called

Sn –Vr myAssembly.dll

• Just before shipping, you submit the assembly to your organization signing authority
for the actual strong name signing using the –R option with the Strong Name tool. The
following example signs an assembly called myAssembly.dll with a strong name using the
sgKey.snk key pair.

Sn -R myAssembly.dll sgKey.snk

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