SignerInfo Class
The SignerInfo class represents a signer associated with a SignedCms object that represents a CMS/PKCS #7 message.
Namespace: System.Security.Cryptography.Pkcs
Assembly: System.Security (in System.Security.dll)
The SignerInfo type exposes the following members.
| Name | Description | |
|---|---|---|
 | Certificate | The Certificate property retrieves the signing certificate associated with the signer information. |
| CounterSignerInfos | The CounterSignerInfos property retrieves the set of counter signers associated with the signer information. |
| DigestAlgorithm | The DigestAlgorithm property retrieves the Oid object that represents the hash algorithm used in the computation of the signatures. |
| SignedAttributes | The SignedAttributes property retrieves the CryptographicAttributeObjectCollection collection of signed attributes that is associated with the signer information. Signed attributes are signed along with the rest of the message content. |
| SignerIdentifier | The SignerIdentifier property retrieves the certificate identifier of the signer associated with the signer information. |
| UnsignedAttributes | The UnsignedAttributes property retrieves the CryptographicAttributeObjectCollection collection of unsigned attributes that is associated with the SignerInfo content. Unsigned attributes can be modified without invalidating the signature. |
| Version | The Version property retrieves the signer information version. |
| Name | Description | |
|---|---|---|
| CheckHash | The CheckHash method verifies the data integrity of the CMS/PKCS #7 message signer information. CheckHash is a specialized method used in specific security infrastructure applications in which the subject uses the HashOnly member of the SubjectIdentifierType enumeration when setting up a CmsSigner object. CheckHash does not authenticate the signer information because this method does not involve verifying a digital signature. For general-purpose checking of the integrity and authenticity of CMS/PKCS #7 message signer information and countersignatures, use the CheckSignature(Boolean) or CheckSignature(X509Certificate2Collection, Boolean) methods. |
| CheckSignature(Boolean) | The CheckSignature(Boolean) method verifies the digital signature of the message and, optionally, validates the certificate. |
| CheckSignature(X509Certificate2Collection, Boolean) | The CheckSignature(X509Certificate2Collection, Boolean) method verifies the digital signature of the message by using the specified collection of certificates and, optionally, validates the certificate. |
| ComputeCounterSignature() | The ComputeCounterSignature() method prompts the user to select a signing certificate, creates a countersignature, and adds the signature to the CMS/PKCS #7 message. Countersignatures are restricted to one level. |
| ComputeCounterSignature(CmsSigner) | The ComputeCounterSignature(CmsSigner) method creates a countersignature by using the specified signer and adds the signature to the CMS/PKCS #7 message. Countersignatures are restricted to one level. |
| Equals(Object) | Determines whether the specified object is equal to the current object. (Inherited from Object.) |
| GetHashCode | Serves as a hash function for a particular type. (Inherited from Object.) |
| GetType | Gets the Type of the current instance. (Inherited from Object.) |
| RemoveCounterSignature(Int32) | The RemoveCounterSignature method removes the countersignature at the specified index of the CounterSignerInfos collection. |
| RemoveCounterSignature(SignerInfo) | The RemoveCounterSignature method removes the countersignature for the specified SignerInfo object. |
| ToString | Returns a string that represents the current object. (Inherited from Object.) |
The signatures represented by the SignerInfo class can be either over message content or a signature. The latter kind of signature is referred to as a countersignature.
This implementation of CMS/PKCS #7 supports only one level of countersignature. That is, a signature can be signed, which forms a countersignature, but that countersignature cannot be signed again.
This class does not have a public constructor; therefore, it cannot be publicly instantiated. It is a read-only class accessible from the SignedCms.SignerInfos property.
| Note |
|---|
The HostProtectionAttribute attribute applied to this type or member has the following Resources property value: MayLeakOnAbort. The HostProtectionAttribute does not affect desktop applications (which are typically started by double-clicking an icon, typing a command, or entering a URL in a browser). For more information, see the HostProtectionAttribute class or SQL Server Programming and Host Protection Attributes. |
Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
