Dkim VB.NET Reference Documentation

Dkim

DomainKeys API for creating and verifying DKIM-Signature and DomainKey-Signature MIME (email) header fields. This API is included with the "Chilkat MIME" license. ("Chilkat MIME" may be referred to as "Chilkat S/MIME" on some chilkatsoft.com web pages. They are the same product.)

Object Creation

Dim obj As New Chilkat.Dkim()

Properties

AbortCurrent As Boolean

Introduced in version 9.5.0.58

When set to True, causes the currently running method to abort. Methods that always finish quickly (i.e.have no length file operations or network communications) are not affected. If no method is running, then this property is automatically reset to False when the next method is called. When the abort occurs, this property is reset to False. Both synchronous and asynchronous method calls can be aborted. (A synchronous method call could be aborted by setting this property from a separate thread.)

DebugLogFilePath As String

If set to a file path, causes each Chilkat method or property call to automatically append it's LastErrorText to the specified log file. The information is appended such that if a hang or crash occurs, it is possible to see the context in which the problem occurred, as well as a history of all Chilkat calls up to the point of the problem. The VerboseLogging property can be set to provide more detailed information.

This property is typically used for debugging the rare cases where a Chilkat method call hangs or generates an exception that halts program execution (i.e. crashes). A hang or crash should generally never happen. The typical causes of a hang are:

  1. a timeout related property was set to 0 to explicitly indicate that an infinite timeout is desired,
  2. the hang is actually a hang within an event callback (i.e. it is a hang within the application code), or
  3. there is an internal problem (bug) in the Chilkat code that causes the hang.

DkimAlg As String

The signing algorithm to be used in creating the DKIM-Signature. Possible values are "rsa-sha256" and "rsa-sha1". The default value is "rsa-sha256".

DkimBodyLengthCount As Integer

Optional body length count to set a maximum number of body bytes to be hashed when creating the DKIM-Signature field. The default value is 0, indicating that the entire body should be hashed.

DkimCanon As String

Canonicalization algorithm to be used for both header and body when creating the DKIM-Signature. Possible values are "simple" and "relaxed". The default value is "relaxed".

DkimDomain As String

The domain name of the signing domain when creating the DKIM-Signature.

DkimHeaders As String

A colon-separated list of header field names that identify headers presented to the signing algorithm when creating the DKIM-Signature. The default value is: "mime-version:date:message-id:subject:from:to:content-type".

DkimSelector As String

The selector to be used to form the DNS query for the public key. This property applies to creating a DKIM-Signature. For example, if the selector is "reykjavik" and the domain is "example-code.com", then the DNS query would be for "reykjavik._domainkey.example-code.com".

DomainKeyAlg As String

The signing algorithm to be used in creating the DomainKey-Signature. The only possible value is "rsa-sha1". The default value is "rsa-sha1".

DomainKeyCanon As String

Canonicalization algorithm to be used for when creating the DomainKey-Signature. Possible values are "simple" and "nofws". The default value is "nofws".

DomainKeyDomain As String

The domain name of the signing domain when creating the DomainKey-Signature.

DomainKeyHeaders As String

A colon-separated list of header field names that identify headers presented to the signing algorithm when creating the DomainKey-Signature. The default value is: "mime-version:date:message-id:subject:from:to:content-type".

DomainKeySelector As String

The selector to be used to form the DNS query for the public key. This property applies to creating a DomainKey-Signature. For example, if the selector is "reykjavik" and the domain is "example-code.com", then the DNS query would be for "reykjavik._domainkey.example-code.com".

HeartbeatMs As Integer

The number of milliseconds between each AbortCheck event callback. The AbortCheck callback allows an application to abort any method call prior to completion. If HeartbeatMs is 0 (the default), no AbortCheck event callbacks will fire.

LastErrorHtml As String (ReadOnly)

Provides information in HTML format about the last method/property called. If a method call returns a value indicating failure, or behaves unexpectedly, examine this property to get more information.

LastErrorText As String (ReadOnly)

Provides information in plain-text format about the last method/property called. If a method call returns a value indicating failure, or behaves unexpectedly, examine this property to get more information.

Concept of LastErrorText

LastErrorText Standard Information

LastErrorXml As String (ReadOnly)

Provides information in XML format about the last method/property called. If a method call returns a value indicating failure, or behaves unexpectedly, examine this property to get more information.

LastMethodSuccess As Boolean

Introduced in version 9.5.0.52

Indicate whether the last method call succeeded or failed. A value of True indicates success, a value of False indicates failure. This property is automatically set for method calls. It is not modified by property accesses. The property is automatically set to indicate success for the following types of method calls:

  • Any method that returns a string.
  • Any method returning a Chilkat object, binary bytes, or a date/time.
  • Any method returning a standard boolean status value where success = True and failure = False.
  • Any method returning an integer where failure is defined by a return value less than zero.

Note: Methods that do not fit the above requirements will always set this property equal to True. For example, a method that returns no value (such as a "void" in C++) will technically always succeed.

VerboseLogging As Boolean

If set to True, then the contents of LastErrorText (or LastErrorXml, or LastErrorHtml) may contain more verbose information. The default value is False. Verbose logging should only be used for debugging. The potentially large quantity of logged information may adversely affect peformance.

Version As String (ReadOnly)

Version of the component/library, such as "9.5.0.63"

Methods

Function AddDkimSignature(ByVal mimeIn As Byte()) As Byte()

This method is deprecated. It will be removed in a future version.

Constructs and prepends a DKIM-Signature header to the MIME. Prior to calling this method, your program must set both the DkimDomain and DkimSelector properties, and it must load a private key by calling LoadDkimPk or LoadDkimPkFile.

Note: This method is deprecated. Use the DkimSign method instead.

Returns an empty byte array on failure

Add DKIM-Signature Header to MIME / Email

Send DKIM Signed Email

Function AddDomainKeySignature(ByVal mimeIn As Byte()) As Byte()

This method is deprecated. It will be removed in a future version.

Constructs and prepends a DomainKey-Signature header to the MIME. Prior to calling this method, your program must set both the DomainKeyDomain and DomainKeySelector properties, and it must load a private key by calling LoadDomainKeyPk or LoadDomainKeyPkFile.

Note: This method is deprecated. Use the DomainKeySign method instead.

Returns an empty byte array on failure

Add DomainKey-Signature Header to MIME / Email

Function DkimSign(ByVal mimeData As BinData) As Boolean

Introduced in version 9.5.0.71

Constructs and prepends a DKIM-Signature header to the MIME passed in mimeData. Prior to calling this method, your program must set both the DkimDomain and DkimSelector properties, and it must load a private key by calling SetDkimPrivateKey.

Returns True for success, False for failure.

Function DkimVerify(ByVal sigIndex As Integer, ByVal mimeData As BinData) As Boolean

Introduced in version 9.5.0.71

Verifies the Nth DKIM-Signature header in the mimeData. (In most cases, there is only one signature.) The 1st signature is at sigIndex 0.

Important: Many anti-virus programs, such as AVG, will modify the MIME of an email as it is received. This will cause DKIM signature verification to fail because the body of the MIME is modified.

Returns True for success, False for failure.

Function DomainKeySign(ByVal mimeData As BinData) As Boolean

Introduced in version 9.5.0.71

Constructs and prepends a DomainKey-Signature header to the MIME passed in mimeData. Prior to calling this method, your program must set both the DomainKeyDomain and DomainKeySelector properties, and it must load a private key by calling SetDomainKeyPrivateKey.

Returns True for success, False for failure.

Function DomainKeyVerify(ByVal sigIndex As Integer, ByVal mimeData As BinData) As Boolean

Introduced in version 9.5.0.71

Verifies the Nth DomainKey-Signature header in the mimeData. (In most cases, there is only one signature.) The 1st signature is at sigIndex 0.

Important: Many anti-virus programs, such as AVG, will modify the MIME of an email as it is received. This will cause DomainKey signature verification to fail because the body of the MIME is modified.

Returns True for success, False for failure.

Function LoadDkimPk(ByVal privateKey As String, ByVal optionalPassword As String) As Boolean

This method is deprecated. It will be removed in a future version.

Loads an RSA private key to be used for creating a DKIM-Signature. Any valid RSA private key format that is not binary, such as PEM or XML, may be passed to this method. This method will automatically determine the format and parse it correctly. A password is only required if key is encrypted, such as for encrypted PEM.

Note: This method is deprecated. Use the SetDkimPrivateKey method instead.

Returns True for success, False for failure.

DKIM Signature using Windows Current User Certificate Store

Function LoadDkimPkBytes(ByVal privateKeyDer As Byte(), ByVal optionalPassword As String) As Boolean

This method is deprecated. It will be removed in a future version.

Loads an RSA private key to be used for creating a DKIM-Signature. Any valid RSA private key binary format, such as DER, may be passed to this method. This method will automatically determine the format and parse it correctly. A password is only required if key is encrypted.

Note: This method is deprecated. Use the SetDkimPrivateKey method instead.

Returns True for success, False for failure.

Function LoadDkimPkFile(ByVal privateKeyFilePath As String, ByVal optionalPassword As String) As Boolean

This method is deprecated. It will be removed in a future version.

Loads an RSA private key file to be used for creating a DKIM-Signature. The file name contains any valid RSA private key format, such as DER, PKCS8, PEM, XML, etc. This method will automatically determine the format and parse it correctly. A password is only required if key is encrypted, such as for encrypted PEM or encrypted PKCS8.

Note: This method is deprecated. Use the SetDkimPrivateKey method instead.

Returns True for success, False for failure.

Function LoadDomainKeyPk(ByVal privateKey As String, ByVal optionalPassword As String) As Boolean

This method is deprecated. It will be removed in a future version.

Loads an RSA private key to be used for creating a DomainKey-Signature. Any valid RSA private key format that is not binary, such as PEM or XML, may be passed to this method. This method will automatically determine the format and parse it correctly. A password is only required if key is encrypted, such as for encrypted PEM.

Note: This method is deprecated. Use the SetDomainKeyPrivateKey method instead.

Returns True for success, False for failure.

Function LoadDomainKeyPkBytes(ByVal privateKeyDer As Byte(), ByVal optionalPassword As String) As Boolean

This method is deprecated. It will be removed in a future version.

Loads an RSA private key to be used for creating a DomainKey-Signature. Any valid RSA private key binary format, such as DER, may be passed to this method. This method will automatically determine the format and parse it correctly. A password is only required if key is encrypted.

Note: This method is deprecated. Use the SetDomainKeyPrivateKey method instead.

Returns True for success, False for failure.

Function LoadDomainKeyPkFile(ByVal privateKeyFilePath As String, ByVal optionalPassword As String) As Boolean

This method is deprecated. It will be removed in a future version.

Loads an RSA private key file to be used for creating a DomainKey-Signature. The file name contains any valid RSA private key format, such as DER, PKCS8, PEM, XML, etc. This method will automatically determine the format and parse it correctly. A password is only required if key is encrypted, such as for encrypted PEM or encrypted PKCS8.

Note: This method is deprecated. Use the SetDomainKeyPrivateKey method instead.

Returns True for success, False for failure.

Function LoadPublicKey(ByVal selector As String, ByVal domain As String, ByVal publicKey As String) As Boolean

Caches a public key to be used for verifying DKIM and DomainKey signatures for a given selector and domain. The publicKey is a string containing an RSA public key in any text format, such as XML, PEM, etc. This method will automatically detect the format and load the public key correctly. This method is useful for testing DKIM and DomainKey verification when your public key has not yet been installed in DNS.

Returns True for success, False for failure.

Function LoadPublicKeyFile(ByVal selector As String, ByVal domain As String, ByVal publicKeyFilepath As String) As Boolean

Caches a public key to be used for verifying DKIM and DomainKey signatures for a given selector and domain. The publicKeyFilepath is a filepath of an RSA public key in any format. This method will automatically detect the format and load the public key correctly. This method is useful for testing DKIM and DomainKey verification when your public key has not yet been installed in DNS.

Returns True for success, False for failure.

Function NumDkimSignatures(ByVal mimeData As Byte()) As Integer

Returns the number of DKIM-Signature header fields found in mimeData.

Function NumDomainKeySignatures(ByVal mimeData As Byte()) As Integer

Returns the number of DomainKey-Signature header fields found in mimeData.

Function PrefetchPublicKey(ByVal selector As String, ByVal domain As String) As Boolean

Useful if your application is going to verify many emails from a single domain (or a few domains). This eliminates the need to do a DNS lookup to fetch the public key each time an email's DKIM or DomainKey signature is verified.

This method may be called multiple times -- once for each selector/domain to be pre-fetched. The verify methods (VerifyDkimSignature and VerifyDomainKeySignature) will use a pre-fetched key if the selector and domain match.

Returns True for success, False for failure.

Function PrefetchPublicKeyAsync(ByVal selector As String, ByVal domain As String) As Task

Creates an asynchronous task to call the PrefetchPublicKey method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

Note: Async method event callbacks happen in the background thread. Accessing and updating UI elements existing in the main thread may require special considerations.

Returns Nothing on failure

How to Run an Asynchronous Task

Function SaveLastError(ByVal path As String) As Boolean

Saves the last-error information (the contents of LastErrorXml) to an XML formatted file.

Returns True for success, False for failure.

Function SetDkimPrivateKey(ByVal privateKey As PrivateKey) As Boolean

Introduced in version 9.5.0.71

Sets the private key file to be used for creating a DKIM-Signature.

Returns True for success, False for failure.

Function SetDomainKeyPrivateKey(ByVal privateKey As PrivateKey) As Boolean

Introduced in version 9.5.0.71

Sets the private key file to be used for creating a DomainKey-Signature.

Returns True for success, False for failure.

Function UnlockComponent(ByVal unlockCode As String) As Boolean

Unlocks the component allowing for the full functionality to be used. If this method unexpectedly returns False, examine the contents of the LastErrorText property to determine the reason for failure.

Returns True for success, False for failure.

Diagnosing UnlockComponent Problems

UnlockComponent LastErrorText shows exact string passed to it.

Verify UnlockComponent Success w/ Purchased Unlock Code

LastErrorText Standard Information

Function VerifyDkimSignature(ByVal sigIndex As Integer, ByVal mimeData As Byte()) As Boolean

This method is deprecated. It will be removed in a future version.

Verifies the Nth DKIM-Signature header in the mimeData. (In most cases, there is only one signature.) The 1st signature is at sigIndex 0.

Important: Many anti-virus programs, such as AVG, will modify the MIME of an email as it is received. This will cause DKIM signature verification to fail because the body of the MIME is modified.

Note: This method is deprecated. Use the DkimVerify method instead.

Returns True for success, False for failure.

Function VerifyDkimSignatureAsync(ByVal sigIndex As Integer, ByVal mimeData As Byte()) As Task

This method is deprecated. It will be removed in a future version.

Creates an asynchronous task to call the VerifyDkimSignature method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

Note: Async method event callbacks happen in the background thread. Accessing and updating UI elements existing in the main thread may require special considerations.

Returns Nothing on failure

How to Run an Asynchronous Task

Function VerifyDomainKeySignature(ByVal sigIndex As Integer, ByVal mimeData As Byte()) As Boolean

This method is deprecated. It will be removed in a future version.

Verifies the Nth DomainKey-Signature header in the mimeData. (In most cases, there is only one signature.) The 1st signature is at sigIndex 0.

Important: Many anti-virus programs, such as AVG, will modify the MIME of an email as it is received. This will cause DomainKey signature verification to fail because the body of the MIME is modified.

Note: This method is deprecated. Use the DomainKeyVerify method instead.

Returns True for success, False for failure.

Function VerifyDomainKeySignatureAsync(ByVal sigIndex As Integer, ByVal mimeData As Byte()) As Task

This method is deprecated. It will be removed in a future version.

Creates an asynchronous task to call the VerifyDomainKeySignature method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

Note: Async method event callbacks happen in the background thread. Accessing and updating UI elements existing in the main thread may require special considerations.

Returns Nothing on failure

How to Run an Asynchronous Task

Events

Event OnAbortCheck

Provides the opportunity for a method call to be aborted. The AbortCheck event is fired periodically based on the value of the HeartbeatMs property. If HeartbeatMs is 0, then no AbortCheck events will fire. As an example, to fire 5 AbortCheck events per second, set the HeartbeatMs property equal to 200.

Args are passed using Chilkat.AbortCheckEventArgs

Event callback implementation:

Dim WithEvents dkim As Chilkat.Dkim

Private Sub dkim_OnAbortCheck(sender As Object, args As Chilkat.AbortCheckEventArgs) Handles dkim.OnAbortCheck

    ...

End Sub

Event OnBinaryData

Binary data provided by certain methods.

Args are passed using Chilkat.BinaryDataEventArgs

Event callback implementation:

Dim WithEvents dkim As Chilkat.Dkim

Private Sub dkim_OnBinaryData(sender As Object, args As Chilkat.BinaryDataEventArgs) Handles dkim.OnBinaryData

    ...

End Sub

Event OnPercentDone

Provides the percentage completed for any method that involves network communications or time-consuming processing (assuming it is a method where a percentage completion can be measured). This event is only fired when it is possible to know a percentage completion, and when it makes sense to express the operation as a percentage completed. The pctDone argument will have a value from 1 to 100. For operations (Chilkat method calls) that complete very quickly, the number of PercentDone callbacks will vary, but the final callback should have a value of 100. For long running operations, no more than one callback per percentage point will occur (for example: 1, 2, 3, ... 98, 99, 100).

The PercentDone callback counts as an AbortCheck event. For method calls that complete quickly such that PercentDone events fire, it may be that AbortCheck events don't fire because the opportunity to abort is already provided in the PercentDone callback. For time consuming operations, where the amount of time between PercentDone callbacks are long, AbortCheck callbacks may be used to allow for the operation to be aborted in a more responsive manner.

The abort output argument provides a means for aborting the operation. Setting it to True will cause the method to abort and return a failed status (or whatever return value indicates failure).

Args are passed using Chilkat.PercentDoneEventArgs

Event callback implementation:

Dim WithEvents dkim As Chilkat.Dkim

Private Sub dkim_OnPercentDone(sender As Object, args As Chilkat.PercentDoneEventArgs) Handles dkim.OnPercentDone

    ...

End Sub

Event OnProgressInfo

A general name/value event that provides information about what is happening during a method call. To find out what information is available, write code to handle this event and log the name/value pairs. Most are self-explanatory.

Args are passed using Chilkat.ProgressInfoEventArgs

Event callback implementation:

Dim WithEvents dkim As Chilkat.Dkim

Private Sub dkim_OnProgressInfo(sender As Object, args As Chilkat.ProgressInfoEventArgs) Handles dkim.OnProgressInfo

    ...

End Sub

Event OnTaskCompleted

Called in the background thread when an asynchronous task completes.

VB.NET TaskCompleted Event Callback Example

Args are passed using Chilkat.TaskCompletedEventArgs

Event callback implementation:

Dim WithEvents dkim As Chilkat.Dkim

Private Sub dkim_OnTaskCompleted(sender As Object, args As Chilkat.TaskCompletedEventArgs) Handles dkim.OnTaskCompleted

    ...

End Sub

Event OnTextData

Text data provided by certain methods.

Args are passed using Chilkat.TextDataEventArgs

Event callback implementation:

Dim WithEvents dkim As Chilkat.Dkim

Private Sub dkim_OnTextData(sender As Object, args As Chilkat.TextDataEventArgs) Handles dkim.OnTextData

    ...

End Sub