Dkim Delphi DLL Reference Documentation

Dkim

Current Version: 9.5.0.88

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.)

Create/Dispose

var
myObject: HCkDkim;

begin
myObject := CkDkim_Create();

// ...

CkDkim_Dispose(myObject);
end;
function CkDkim_Create: HCkDkim; stdcall;

Creates an instance of the HCkDkim object and returns a handle (i.e. a Pointer). The handle is passed in the 1st argument for the functions listed on this page.

procedure CkDkim_Dispose(handle: HCkDkim); stdcall;

Objects created by calling CkDkim_Create must be freed by calling this method. A memory leak occurs if a handle is not disposed by calling this function.

Properties

AbortCurrent
function CkDkim_getAbortCurrent(objHandle: HCkDkim): wordbool; stdcall;
procedure CkDkim_putAbortCurrent(objHandle: HCkDkim; newPropVal: wordbool); stdcall;
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.)

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DebugLogFilePath
procedure CkDkim_getDebugLogFilePath(objHandle: HCkDkim; outPropVal: HCkString); stdcall;
procedure CkDkim_putDebugLogFilePath(objHandle: HCkDkim; newPropVal: PWideChar); stdcall;
function CkDkim__debugLogFilePath(objHandle: HCkDkim): PWideChar; stdcall;

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.

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DkimAlg
procedure CkDkim_getDkimAlg(objHandle: HCkDkim; outPropVal: HCkString); stdcall;
procedure CkDkim_putDkimAlg(objHandle: HCkDkim; newPropVal: PWideChar); stdcall;
function CkDkim__dkimAlg(objHandle: HCkDkim): PWideChar; stdcall;

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".

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DkimBodyLengthCount
function CkDkim_getDkimBodyLengthCount(objHandle: HCkDkim): Integer; stdcall;
procedure CkDkim_putDkimBodyLengthCount(objHandle: HCkDkim; newPropVal: Integer); stdcall;

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.

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DkimCanon
procedure CkDkim_getDkimCanon(objHandle: HCkDkim; outPropVal: HCkString); stdcall;
procedure CkDkim_putDkimCanon(objHandle: HCkDkim; newPropVal: PWideChar); stdcall;
function CkDkim__dkimCanon(objHandle: HCkDkim): PWideChar; stdcall;

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".

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DkimDomain
procedure CkDkim_getDkimDomain(objHandle: HCkDkim; outPropVal: HCkString); stdcall;
procedure CkDkim_putDkimDomain(objHandle: HCkDkim; newPropVal: PWideChar); stdcall;
function CkDkim__dkimDomain(objHandle: HCkDkim): PWideChar; stdcall;

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

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DkimHeaders
procedure CkDkim_getDkimHeaders(objHandle: HCkDkim; outPropVal: HCkString); stdcall;
procedure CkDkim_putDkimHeaders(objHandle: HCkDkim; newPropVal: PWideChar); stdcall;
function CkDkim__dkimHeaders(objHandle: HCkDkim): PWideChar; stdcall;

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".

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DkimSelector
procedure CkDkim_getDkimSelector(objHandle: HCkDkim; outPropVal: HCkString); stdcall;
procedure CkDkim_putDkimSelector(objHandle: HCkDkim; newPropVal: PWideChar); stdcall;
function CkDkim__dkimSelector(objHandle: HCkDkim): PWideChar; stdcall;

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".

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DomainKeyAlg
procedure CkDkim_getDomainKeyAlg(objHandle: HCkDkim; outPropVal: HCkString); stdcall;
procedure CkDkim_putDomainKeyAlg(objHandle: HCkDkim; newPropVal: PWideChar); stdcall;
function CkDkim__domainKeyAlg(objHandle: HCkDkim): PWideChar; stdcall;

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

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DomainKeyCanon
procedure CkDkim_getDomainKeyCanon(objHandle: HCkDkim; outPropVal: HCkString); stdcall;
procedure CkDkim_putDomainKeyCanon(objHandle: HCkDkim; newPropVal: PWideChar); stdcall;
function CkDkim__domainKeyCanon(objHandle: HCkDkim): PWideChar; stdcall;

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

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DomainKeyDomain
procedure CkDkim_getDomainKeyDomain(objHandle: HCkDkim; outPropVal: HCkString); stdcall;
procedure CkDkim_putDomainKeyDomain(objHandle: HCkDkim; newPropVal: PWideChar); stdcall;
function CkDkim__domainKeyDomain(objHandle: HCkDkim): PWideChar; stdcall;

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

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DomainKeyHeaders
procedure CkDkim_getDomainKeyHeaders(objHandle: HCkDkim; outPropVal: HCkString); stdcall;
procedure CkDkim_putDomainKeyHeaders(objHandle: HCkDkim; newPropVal: PWideChar); stdcall;
function CkDkim__domainKeyHeaders(objHandle: HCkDkim): PWideChar; stdcall;

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".

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DomainKeySelector
procedure CkDkim_getDomainKeySelector(objHandle: HCkDkim; outPropVal: HCkString); stdcall;
procedure CkDkim_putDomainKeySelector(objHandle: HCkDkim; newPropVal: PWideChar); stdcall;
function CkDkim__domainKeySelector(objHandle: HCkDkim): PWideChar; stdcall;

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".

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HeartbeatMs
function CkDkim_getHeartbeatMs(objHandle: HCkDkim): Integer; stdcall;
procedure CkDkim_putHeartbeatMs(objHandle: HCkDkim; newPropVal: Integer); stdcall;

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.

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LastErrorHtml
procedure CkDkim_getLastErrorHtml(objHandle: HCkDkim; outPropVal: HCkString); stdcall;
function CkDkim__lastErrorHtml(objHandle: HCkDkim): PWideChar; stdcall;

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.

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LastErrorText
procedure CkDkim_getLastErrorText(objHandle: HCkDkim; outPropVal: HCkString); stdcall;
function CkDkim__lastErrorText(objHandle: HCkDkim): PWideChar; stdcall;

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.

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LastErrorXml
procedure CkDkim_getLastErrorXml(objHandle: HCkDkim; outPropVal: HCkString); stdcall;
function CkDkim__lastErrorXml(objHandle: HCkDkim): PWideChar; stdcall;

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.

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LastMethodSuccess
function CkDkim_getLastMethodSuccess(objHandle: HCkDkim): wordbool; stdcall;
procedure CkDkim_putLastMethodSuccess(objHandle: HCkDkim; newPropVal: wordbool); stdcall;
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.

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VerboseLogging
function CkDkim_getVerboseLogging(objHandle: HCkDkim): wordbool; stdcall;
procedure CkDkim_putVerboseLogging(objHandle: HCkDkim; newPropVal: wordbool); stdcall;

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.

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VerifyInfo
procedure CkDkim_getVerifyInfo(objHandle: HCkDkim; outPropVal: HCkString); stdcall;
function CkDkim__verifyInfo(objHandle: HCkDkim): PWideChar; stdcall;
Introduced in version 9.5.0.76

Contains JSON with information about the last DKIM or DomainKey signature verified (or verification failure). The JSON will contain information like this:

{
  "domain": "amazonses.com",
  "selector": "7v7vs6w47njt4pimodk5mmttbegzsi6n",
  "publicKey": "MIGfMA0GCSq...z6uqeQIDAQAB",
  "canonicalization": "relaxed/simple",
  "algorithm": "rsa-sha256",
  "signedHeaders": "Subject:From:To:Date:Mime-Version:Content-Type:References:Message-Id:Feedback-ID",
  "verified": "yes"
}

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Version
procedure CkDkim_getVersion(objHandle: HCkDkim; outPropVal: HCkString); stdcall;
function CkDkim__version(objHandle: HCkDkim): PWideChar; stdcall;

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

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Methods

DkimSign
function CkDkim_DkimSign(objHandle: HCkDkim;
    mimeData: HCkBinData): wordbool; stdcall;
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.

More Information and Examples
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DkimVerify
function CkDkim_DkimVerify(objHandle: HCkDkim;
    sigIndex: Integer;
    mimeData: HCkBinData): wordbool; stdcall;
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.

On return, the VerifyInfo property will contain additional information about the DKIM-Signature that was verified (or not verified).

Returns True for success, False for failure.

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DomainKeySign
function CkDkim_DomainKeySign(objHandle: HCkDkim;
    mimeData: HCkBinData): wordbool; stdcall;
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.

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DomainKeyVerify
function CkDkim_DomainKeyVerify(objHandle: HCkDkim;
    sigIndex: Integer;
    mimeData: HCkBinData): wordbool; stdcall;
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.

On return, the VerifyInfo property will contain additional information about the DKIM-Signature that was verified (or not verified).

Returns True for success, False for failure.

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LoadPublicKey
function CkDkim_LoadPublicKey(objHandle: HCkDkim;
    selector: PWideChar;
    domain: PWideChar;
    publicKey: PWideChar): wordbool; stdcall;

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.

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LoadPublicKeyFile
function CkDkim_LoadPublicKeyFile(objHandle: HCkDkim;
    selector: PWideChar;
    domain: PWideChar;
    publicKeyFilepath: PWideChar): wordbool; stdcall;

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.

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LoadTaskCaller
function CkDkim_LoadTaskCaller(objHandle: HCkDkim;
    task: HCkTask): wordbool; stdcall;
Introduced in version 9.5.0.80

Loads the caller of the task's async method.

Returns True for success, False for failure.

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NumDkimSigs
function CkDkim_NumDkimSigs(objHandle: HCkDkim;
    mimeData: HCkBinData): Integer; stdcall;
Introduced in version 9.5.0.76

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

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NumDomainKeySigs
function CkDkim_NumDomainKeySigs(objHandle: HCkDkim;
    mimeData: HCkBinData): Integer; stdcall;
Introduced in version 9.5.0.76

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

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PrefetchPublicKey
function CkDkim_PrefetchPublicKey(objHandle: HCkDkim;
    selector: PWideChar;
    domain: PWideChar): wordbool; stdcall;

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.

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PrefetchPublicKeyAsync (1)
function CkDkim_PrefetchPublicKeyAsync(objHandle: HCkDkim;
    selector: PWideChar;
    domain: PWideChar): HCkTask; stdcall;

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 nil on failure

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SetDkimPrivateKey
function CkDkim_SetDkimPrivateKey(objHandle: HCkDkim;
    privateKey: HCkPrivateKey): wordbool; stdcall;
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.

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SetDomainKeyPrivateKey
function CkDkim_SetDomainKeyPrivateKey(objHandle: HCkDkim;
    privateKey: HCkPrivateKey): wordbool; stdcall;
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.

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Events

Chilkat supports event callbacks for the Delphi DLL starting in version 9.5.0.82.

AbortCheck
function MyAbortCheck(): Integer; cdecl;
Introduced in version 9.5.0.82

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. Return True to abort; return False to continue (not abort)

More Information and Examples
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PercentDone
function MyPercentDone(pctDone: Integer): Integer; cdecl;
Introduced in version 9.5.0.82

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.

Return True to abort; return False to continue (not abort)

More Information and Examples
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ProgressInfo
procedure MyProgressInfo(name: PWideChar; value: PWideChar) cdecl;
Introduced in version 9.5.0.82

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.

More Information and Examples
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TaskCompleted
procedure MyTaskCompleted(task: HCkTask) cdecl;
Introduced in version 9.5.0.82

Called in the background thread when an asynchronous task completes.

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