Dkim Objective-C Reference Documentation
CkoDkim
Current Version: 11.1.0
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
CkoDkim *obj = [[CkoDkim alloc] init];
Properties
AbortCurrent
When set to YES, 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 NO when the next method is called. When the abort occurs, this property is reset to NO. 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
If set to a file path, this property logs the LastErrorText of each Chilkat method or property call to the specified file. This logging helps identify the context and history of Chilkat calls leading up to any crash or hang, aiding in debugging.
Enabling the VerboseLogging property provides more detailed information. This property is mainly used for debugging rare instances where a Chilkat method call causes a hang or crash, which should generally not happen.
Possible causes of hangs include:
- A timeout property set to 0, indicating an infinite timeout.
- A hang occurring within an event callback in the application code.
- An internal bug in the Chilkat code causing the hang.
DkimAlg
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
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.
topDkimCanon
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
The domain name of the signing domain when creating the DKIM-Signature.
topDkimHeaders
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
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
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
Canonicalization algorithm to be used for when creating the DomainKey-Signature. Possible values are simple and nofws. The default value is nofws.
DomainKeyDomain
The domain name of the signing domain when creating the DomainKey-Signature.
topDomainKeyHeaders
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
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
The interval in milliseconds between each AbortCheck event callback, which enables an application to abort certain method calls before they complete. By default, HeartbeatMs is set to 0, meaning no AbortCheck event callbacks will trigger.
LastErrorHtml
Provides HTML-formatted information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.
topLastErrorText
Provides plain text information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.
LastErrorXml
Provides XML-formatted information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.
topLastMethodSuccess
Indicates the success or failure of the most recent method call: YES means success, NO means failure. This property remains unchanged by property setters or getters. This method is present to address challenges in checking for null or Nothing returns in certain programming languages.
VerboseLogging
If set to YES, then the contents of LastErrorText (or LastErrorXml, or LastErrorHtml) may contain more verbose information. The default value is NO. Verbose logging should only be used for debugging. The potentially large quantity of logged information may adversely affect peformance.
VerifyInfo
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"
}
Version
Methods
DkimSign
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 YES for success, NO for failure.
DkimVerify
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 YES for success, NO for failure.
DomainKeySign
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 YES for success, NO for failure.
topDomainKeyVerify
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 YES for success, NO for failure.
LoadPublicKey
domain:(NSString *)domain
publicKey:(NSString *)publicKey;
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 YES for success, NO for failure.
topLoadPublicKeyFile
domain:(NSString *)domain
publicKeyFilepath:(NSString *)publicKeyFilepath;
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 YES for success, NO for failure.
topLoadTaskCaller
NumDkimSigs
Returns the number of DKIM-Signature header fields found in mimeData.
NumDomainKeySigs
Returns the number of DomainKey-Signature header fields found in mimeData.
PrefetchPublicKey
domain:(NSString *)domain;
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 YES for success, NO for failure.
topPrefetchPublicKeyAsync (1)
Creates an asynchronous task to call the PrefetchPublicKey method with the arguments provided.
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
SetDkimPrivateKey
Sets the private key file to be used for creating a DKIM-Signature.
Returns YES for success, NO for failure.
topSetDomainKeyPrivateKey
Sets the private key file to be used for creating a DomainKey-Signature.
Returns YES for success, NO for failure.
topEvents
To implement an event callback, your application would define and implement a class that inherits from CkoBaseProgress. Your application can implement methods to override some or all of the default/empty method implementations of the CkoBaseProgress base class.
For example:
CkoDkim *dkim = [[CkoDkim alloc] init]; MyDkimProgress *callbackObj = [[MyDkimProgress alloc] init]; [dkim setEventCallbackObject:callbackObj];
MyDkimProgress interface example:
#import "CkoDkimProgress.h"
@interface MyDkimProgress : CkoBaseProgress {
}
- (id)init;
- (void)dealloc;
- (void)dispose;
- (void)AbortCheck:(BOOL *)abort;
- (void)PercentDone:(NSNumber *)pctDone
abort:(BOOL *)abort;
- (void)ProgressInfo:(NSString *)name
value:(NSString *)value;
- (void)TaskCompleted:(CkoTask *)task;
@endAbortCheck
Enables a method call to be aborted by triggering the AbortCheck event at intervals defined by the HeartbeatMs property. If HeartbeatMs is set to its default value of 0, no events will occur. For instance, set HeartbeatMs to 200 to trigger 5 AbortCheck events per second.
PercentDone
abort:(BOOL *)abort;
This provides the percentage completion for any method involving network communications or time-consuming processing, assuming the progress can be measured as a percentage. This event is triggered only when it's possible and logical to express the operation's progress as a percentage. The pctDone argument will range from 1 to 100. For methods that finish quickly, the number of PercentDone callbacks may vary, but the final callback will have pctDone equal to 100. For longer operations, callbacks will not exceed one per percentage point (e.g., 1, 2, 3, ..., 98, 99, 100).
The PercentDone callback also acts as an AbortCheck event. For fast methods where PercentDone fires, an AbortCheck event may not trigger since the PercentDone callback already provides an opportunity to abort. For longer operations, where time between PercentDone callbacks is extended, AbortCheck callbacks enable more responsive operation termination.
To abort the operation, set the abort output argument to YES. This will cause the method to terminate and return a failure status or corresponding failure value.
ProgressInfo
value:(NSString *)value;
This event callback provides tag name/value pairs that detail what occurs during a method call. To discover existing tag names, create code to handle the event, emit the pairs, and review them. Most tag names are self-explanatory.
TaskCompleted
Called from the background thread when an asynchronous task completes.