MessageDecryptor Component

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The MessageDecryptor component decrypts data that is stored in the PKCS#7 format.

Syntax

TsbxMessageDecryptor

Remarks

PKCS#7 (Public Key Cryptography Standard #7) is a common format used to store encrypted and signed data. It is used by a variety of protocols, including S/MIME and CMS.

MessageDecryptor is capable of decrypting encrypted PKCS#7 data stored in EnvelopedData (asymmetric encryption) and EncryptedData (symmetric encryption) subformats. RSA and ECDH key wrapping and all popular symmetric encryption algorithms are supported.

Setting up and using MessageDecryptor is easy:

• Set up your source and destination via InputFile (InputBytes) and OutputFile (OutputBytes) properties.
• For certificate-based (asymmetric) encryption, put the decryption certificate (with its private key included) to the Certificates collection.
• For key-based (symmetric) encryption, assign the symmetric key to Key property. Note: you can find out whether asymmetric or symmetric encryption was used on the input message using the CheckEncryptionType method.
• Call Decrypt to execute the operation.

Note that MessageDecryptor only works with binary PKCS#7-compliant encrypted messages. For processing encrypted S/MIME emails, see MailReader. For decrypting PGP messages, see PGPReader. For raw symmetric encryption, see SymmetricCrypto. For processing XML-ENC messages, see XMLDecryptor. MessageDecryptor decryptor = new MessageDecryptor(); // Select the file which contains the message that will be decrypted decryptor.setInputFile("encryptedMessage.bin"); // Select the file where the decrypted message will be written decryptor.setOutputFile("decryptedMessage.txt"); // Providing the certificate with its private key to decrypt data CertificateList certificateList = new CertificateList(); certificateList.add(new Certificate("cert.pfx","password")); decryptor.setCertificates(certificateList); decryptor.decrypt(); // Decrypt

Property List

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The following is the full list of the properties of the component with short descriptions. Click on the links for further details.

Method List

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The following is the full list of the methods of the component with short descriptions. Click on the links for further details.

Event List

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The following is the full list of the events fired by the component with short descriptions. Click on the links for further details.

Config Settings

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The following is a list of config settings for the component with short descriptions. Click on the links for further details.

CertificateIndex Property (MessageDecryptor Component)

The index of certificate that was used to decrypt the message.

Syntax

__property int CertificateIndex = { read=FCertificateIndex };

Default Value

-1

Remarks

This property contains the index of certificate (one of those residing in Certificates collection) that was used to decrypt the message.

This property is read-only.

Data Type

Integer

CertCount Property (MessageDecryptor Component)

The number of records in the Cert arrays.

Syntax

__property int CertCount = { read=FCertCount, write=FSetCertCount };

Default Value

0

Remarks

This property controls the size of the following arrays:

• CertBytes
• CertHandle

The array indices start at 0 and end at CertCount - 1.

This property is not available at design time.

Data Type

Integer

CertBytes Property (MessageDecryptor Component)

Returns the raw certificate data in DER format.

Syntax

__property DynamicArray CertBytes[int CertIndex] = { read=FCertBytes };

Remarks

Returns the raw certificate data in DER format.

The CertIndex parameter specifies the index of the item in the array. The size of the array is controlled by the CertCount property.

This property is read-only and not available at design time.

Data Type

Byte Array

CertHandle Property (MessageDecryptor Component)

Allows to get or set a 'handle', a unique identifier of the underlying property object.

Syntax

__property __int64 CertHandle[int CertIndex] = { read=FCertHandle, write=FSetCertHandle };

Default Value

0

Remarks

Allows to get or set a 'handle', a unique identifier of the underlying property object. Use this property to assign objects of the same type in a quicker manner, without copying them fieldwise.

When you pass a handle of one object to another, the source object is copied to the destination rather than assigned. It is safe to get rid of the original object after such operation. pdfSigner.setSigningCertHandle(certMgr.getCertHandle());

The CertIndex parameter specifies the index of the item in the array. The size of the array is controlled by the CertCount property.

This property is not available at design time.

Data Type

Long64

EncryptionAlgorithm Property (MessageDecryptor Component)

The symmetric cipher that was used to encrypt the data.

Syntax

__property String EncryptionAlgorithm = { read=FEncryptionAlgorithm };

Default Value

""

Remarks

This property contains the symmetric algorithm that the creator had used to encrypt the message.

This property is read-only and not available at design time.

Data Type

String

EncryptionType Property (MessageDecryptor Component)

Specifies the kind of encrypted message to create.

Syntax

__property TsbxMessageDecryptorEncryptionTypes EncryptionType = { read=FEncryptionType };

enum TsbxMessageDecryptorEncryptionTypes {
  metUnknown=0,
  metCertEncrypted=1,
  metKeyEncrypted=2,
  metCertEncryptedAndAuthenticated=3
};

Default Value

metUnknown

Remarks

Possible values:

This property is read-only.

Data Type

Integer

ExternalCryptoAsyncDocumentID Property (MessageDecryptor Component)

Specifies an optional document ID for SignAsyncBegin() and SignAsyncEnd() calls.

Syntax

__property String ExternalCryptoAsyncDocumentID = { read=FExternalCryptoAsyncDocumentID, write=FSetExternalCryptoAsyncDocumentID };

Default Value

""

Remarks

Specifies an optional document ID for SignAsyncBegin() and SignAsyncEnd() calls.

Use this property when working with multi-signature DCAuth requests and responses to uniquely identify documents signed within a larger batch. On the completion stage, this value helps the signing component identify the correct signature in the returned batch of responses.

If using batched requests, make sure to set this property to the same value on both the pre-signing (SignAsyncBegin) and completion (SignAsyncEnd) stages.

Data Type

String

ExternalCryptoCustomParams Property (MessageDecryptor Component)

Custom parameters to be passed to the signing service (uninterpreted).

Syntax

__property String ExternalCryptoCustomParams = { read=FExternalCryptoCustomParams, write=FSetExternalCryptoCustomParams };

Default Value

""

Remarks

Custom parameters to be passed to the signing service (uninterpreted).

This property is not available at design time.

Data Type

String

ExternalCryptoData Property (MessageDecryptor Component)

Additional data to be included in the async state and mirrored back by the requestor.

Syntax

__property String ExternalCryptoData = { read=FExternalCryptoData, write=FSetExternalCryptoData };

Default Value

""

Remarks

Additional data to be included in the async state and mirrored back by the requestor.

This property is not available at design time.

Data Type

String

ExternalCryptoExternalHashCalculation Property (MessageDecryptor Component)

Specifies whether the message hash is to be calculated at the external endpoint.

Syntax

__property bool ExternalCryptoExternalHashCalculation = { read=FExternalCryptoExternalHashCalculation, write=FSetExternalCryptoExternalHashCalculation };

Default Value

false

Remarks

Specifies whether the message hash is to be calculated at the external endpoint. Please note that this mode is not supported by the DCAuth component.

If set to true, the component will pass a few kilobytes of to-be-signed data from the document to the OnExternalSign event. This only applies when SignExternal() is called.

Data Type

Boolean

ExternalCryptoHashAlgorithm Property (MessageDecryptor Component)

Specifies the request's signature hash algorithm.

Syntax

__property String ExternalCryptoHashAlgorithm = { read=FExternalCryptoHashAlgorithm, write=FSetExternalCryptoHashAlgorithm };

Default Value

"SHA256"

Remarks

Specifies the request's signature hash algorithm.

Data Type

String

ExternalCryptoKeyID Property (MessageDecryptor Component)

The ID of the pre-shared key used for DC request authentication.

Syntax

__property String ExternalCryptoKeyID = { read=FExternalCryptoKeyID, write=FSetExternalCryptoKeyID };

Default Value

""

Remarks

The ID of the pre-shared key used for DC request authentication.

Asynchronous DCAuth-driven communication requires that parties authenticate each other with a secret pre-shared cryptographic key. This provides an extra protection layer for the protocol and diminishes the risk of the private key becoming abused by foreign parties. Use this property to provide the pre-shared key identifier, and use ExternalCryptoKeySecret to pass the key itself.

The same KeyID/KeySecret pair should be used on the DCAuth side for the signing requests to be accepted.

Note: The KeyID/KeySecret scheme is very similar to the AuthKey scheme used in various Cloud service providers to authenticate users.

Example: signer.ExternalCrypto.KeyID = "MainSigningKey"; signer.ExternalCrypto.KeySecret = "abcdef0123456789";

Data Type

String

ExternalCryptoKeySecret Property (MessageDecryptor Component)

The pre-shared key used for DC request authentication.

Syntax

__property String ExternalCryptoKeySecret = { read=FExternalCryptoKeySecret, write=FSetExternalCryptoKeySecret };

Default Value

""

Remarks

The pre-shared key used for DC request authentication. This key must be set and match the key used by the DCAuth counterpart for the scheme to work.

Read more about configuring authentication in the ExternalCryptoKeyID topic.

Data Type

String

ExternalCryptoMethod Property (MessageDecryptor Component)

Specifies the asynchronous signing method.

Syntax

__property TsbxMessageDecryptorExternalCryptoMethods ExternalCryptoMethod = { read=FExternalCryptoMethod, write=FSetExternalCryptoMethod };

enum TsbxMessageDecryptorExternalCryptoMethods {
  asmdPKCS1=0,
  asmdPKCS7=1
};

Default Value

asmdPKCS1

Remarks

Specifies the asynchronous signing method. This is typically defined by the DC server capabilities and setup.

Available options:

Data Type

Integer

ExternalCryptoMode Property (MessageDecryptor Component)

Specifies the external cryptography mode.

Syntax

__property TsbxMessageDecryptorExternalCryptoModes ExternalCryptoMode = { read=FExternalCryptoMode, write=FSetExternalCryptoMode };

enum TsbxMessageDecryptorExternalCryptoModes {
  ecmDefault=0,
  ecmDisabled=1,
  ecmGeneric=2,
  ecmDCAuth=3,
  ecmDCAuthJSON=4
};

Default Value

ecmDefault

Remarks

Specifies the external cryptography mode.

Available options:

This property is not available at design time.

Data Type

Integer

ExternalCryptoPublicKeyAlgorithm Property (MessageDecryptor Component)

Provide the public key algorithm here if the certificate is not available on the pre-signing stage.

Syntax

__property String ExternalCryptoPublicKeyAlgorithm = { read=FExternalCryptoPublicKeyAlgorithm, write=FSetExternalCryptoPublicKeyAlgorithm };

Default Value

""

Remarks

Provide the public key algorithm here if the certificate is not available on the pre-signing stage.

Data Type

String

FIPSMode Property (MessageDecryptor Component)

Reserved.

Syntax

__property bool FIPSMode = { read=FFIPSMode, write=FSetFIPSMode };

Default Value

false

Remarks

This property is reserved for future use.

Data Type

Boolean

InputBytes Property (MessageDecryptor Component)

Use this property to pass the input to component in byte array form.

Syntax

__property DynamicArray InputBytes = { read=FInputBytes, write=FSetInputBytes };

Remarks

Assign a byte array containing the data to be processed to this property.

This property is not available at design time.

Data Type

Byte Array

InputFile Property (MessageDecryptor Component)

Path to the file containing the encrypted message.

Syntax

__property String InputFile = { read=FInputFile, write=FSetInputFile };

Default Value

""

Remarks

Use this property to provide a file containing the encrypted data.

Data Type

String

Key Property (MessageDecryptor Component)

The symmetric key to use for decryption.

Syntax

__property DynamicArray Key = { read=FKey, write=FSetKey };

Remarks

Use this property to provide the symmetric key to decrypt the data. This property is only applicable for processing data of EncryptedData subtype.

Assign this property before calling Decrypt.

This property is not available at design time.

Data Type

Byte Array

OutputBytes Property (MessageDecryptor Component)

Use this property to read the output the component object has produced.

Syntax

__property DynamicArray OutputBytes = { read=FOutputBytes };

Remarks

Read the contents of this property after the operation has completed to read the produced output. This property will only be set if the OutputFile and OutputStream properties had not been assigned.

This property is read-only and not available at design time.

Data Type

Byte Array

OutputFile Property (MessageDecryptor Component)

Path to the file to save the decrypted data to.

Syntax

__property String OutputFile = { read=FOutputFile, write=FSetOutputFile };

Default Value

""

Remarks

Use this property to specify the output file where the decrypted message should be saved.

Data Type

String

SignedAttributeCount Property (MessageDecryptor Component)

The number of records in the SignedAttribute arrays.

Syntax

__property int SignedAttributeCount = { read=FSignedAttributeCount };

Default Value

0

Remarks

This property controls the size of the following arrays:

• SignedAttributeOID
• SignedAttributeValue

The array indices start at 0 and end at SignedAttributeCount - 1.

This property is read-only and not available at design time.

Data Type

Integer

SignedAttributeOID Property (MessageDecryptor Component)

The object identifier of the attribute.

Syntax

__property String SignedAttributeOID[int SignedAttributeIndex] = { read=FSignedAttributeOID };

Default Value

""

Remarks

The object identifier of the attribute.

The SignedAttributeIndex parameter specifies the index of the item in the array. The size of the array is controlled by the SignedAttributeCount property.

This property is read-only and not available at design time.

Data Type

String

SignedAttributeValue Property (MessageDecryptor Component)

The value of the attribute.

Syntax

__property DynamicArray SignedAttributeValue[int SignedAttributeIndex] = { read=FSignedAttributeValue };

Remarks

The value of the attribute.

The SignedAttributeIndex parameter specifies the index of the item in the array. The size of the array is controlled by the SignedAttributeCount property.

This property is read-only and not available at design time.

Data Type

Byte Array

UnsignedAttributeCount Property (MessageDecryptor Component)

The number of records in the UnsignedAttribute arrays.

Syntax

__property int UnsignedAttributeCount = { read=FUnsignedAttributeCount };

Default Value

0

Remarks

This property controls the size of the following arrays:

• UnsignedAttributeOID
• UnsignedAttributeValue

The array indices start at 0 and end at UnsignedAttributeCount - 1.

This property is read-only and not available at design time.

Data Type

Integer

UnsignedAttributeOID Property (MessageDecryptor Component)

The object identifier of the attribute.

Syntax

__property String UnsignedAttributeOID[int UnsignedAttributeIndex] = { read=FUnsignedAttributeOID };

Default Value

""

Remarks

The object identifier of the attribute.

The UnsignedAttributeIndex parameter specifies the index of the item in the array. The size of the array is controlled by the UnsignedAttributeCount property.

This property is read-only and not available at design time.

Data Type

String

UnsignedAttributeValue Property (MessageDecryptor Component)

The value of the attribute.

Syntax

__property DynamicArray UnsignedAttributeValue[int UnsignedAttributeIndex] = { read=FUnsignedAttributeValue };

Remarks

The value of the attribute.

The UnsignedAttributeIndex parameter specifies the index of the item in the array. The size of the array is controlled by the UnsignedAttributeCount property.

This property is read-only and not available at design time.

Data Type

Byte Array

CheckEncryptionType Method (MessageDecryptor Component)

Determines the type of encrypted message in the supplied file.

Syntax

int __fastcall CheckEncryptionType();

Remarks

Use this method to determine the kind of the signature stored in InputFile (InputStream).

Config Method (MessageDecryptor Component)

Sets or retrieves a configuration setting.

Syntax

String __fastcall Config(String ConfigurationString);

Remarks

Config is a generic method available in every component. It is used to set and retrieve configuration settings for the component.

These settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the component, access to these internal properties is provided through the Config method.

To set a configuration setting named PROPERTY, you must call Config("PROPERTY=VALUE"), where VALUE is the value of the setting expressed as a string. For boolean values, use the strings "True", "False", "0", "1", "Yes", or "No" (case does not matter).

To read (query) the value of a configuration setting, you must call Config("PROPERTY"). The value will be returned as a string.

Decrypt Method (MessageDecryptor Component)

Attempts to decrypt an encrypted PKCS#7 message.

Syntax

void __fastcall Decrypt();

Remarks

Call this method to attempt to decrypt the PKCS#7 encrypted data. This call supports EnvelopedData and EncryptedData subtypes on input.

Use InputFile or InputStream property to provide the data, and either Certificates or Key to supply the decryption key material.

When processing enveloped data, the component may fire RecipientFound event to report recipient information.

DoAction Method (MessageDecryptor Component)

Performs an additional action.

Syntax

String __fastcall DoAction(String ActionID, String ActionParams);

Remarks

DoAction is a generic method available in every component. It is used to perform an additional action introduced after the product major release. The list of actions is not fixed, and may be flexibly extended over time.

The unique identifier (case insensitive) of the action is provided in the ActionID parameter.

ActionParams contains the value of a single parameter, or a list of multiple parameters for the action in the form of PARAM1=VALUE1;PARAM2=VALUE2;....

Common ActionIDs:

Reset Method (MessageDecryptor Component)

Resets the component settings.

Syntax

void __fastcall Reset();

Remarks

Reset is a generic method available in every component.

Error Event (MessageDecryptor Component)

Information about errors during PKCS#7 message decryption.

Syntax

typedef struct {
  int ErrorCode;
  String Description;
} TsbxMessageDecryptorErrorEventParams;
typedef void __fastcall (__closure *TsbxMessageDecryptorErrorEvent)(System::TObject* Sender, TsbxMessageDecryptorErrorEventParams *e);
__property TsbxMessageDecryptorErrorEvent OnError = { read=FOnError, write=FOnError };

Remarks

The event is fired in case of exceptional conditions during message processing.

ErrorCode contains an error code and Description contains a textual description of the error. For a list of valid error codes and their descriptions, please refer to the Messages section.

ExternalDecrypt Event (MessageDecryptor Component)

Handles remote or external decryption.

Syntax

typedef struct {
  String OperationId;
  String Algorithm;
  String Pars;
  String EncryptedData;
  String Data;
} TsbxMessageDecryptorExternalDecryptEventParams;
typedef void __fastcall (__closure *TsbxMessageDecryptorExternalDecryptEvent)(System::TObject* Sender, TsbxMessageDecryptorExternalDecryptEventParams *e);
__property TsbxMessageDecryptorExternalDecryptEvent OnExternalDecrypt = { read=FOnExternalDecrypt, write=FOnExternalDecrypt };

Remarks

Assign a handler to this event if you need to delegate a low-level decryption operation to an external, remote, or custom decryption engine. The handler receives an encrypted value in the EncryptedData parameter, and is expected to decrypt it and place the decrypted value into the Data parameter.

OperationId provides a comment about the operation and its origin. It depends on the exact component being used, and may be empty. Algorithm specifies the encryption algorithm being used, and Pars contains algorithm-dependent parameters.

The component uses base16 (hex) encoding for the EncryptedData, Data, and Pars parameters. If your decryption engine uses a different input and output encoding, you may need to decode and/or encode the data before and/or after the decryption.

Sample data encoded in base16: a0dee2a0382afbb09120ffa7ccd8a152 - lower case base16 A0DEE2A0382AFBB09120FFA7CCD8A152 - upper case base16

Notification Event (MessageDecryptor Component)

This event notifies the application about an underlying control flow event.

Syntax

typedef struct {
  String EventID;
  String EventParam;
} TsbxMessageDecryptorNotificationEventParams;
typedef void __fastcall (__closure *TsbxMessageDecryptorNotificationEvent)(System::TObject* Sender, TsbxMessageDecryptorNotificationEventParams *e);
__property TsbxMessageDecryptorNotificationEvent OnNotification = { read=FOnNotification, write=FOnNotification };

Remarks

The component fires this event to let the application know about some event, occurrence, or milestone in the component. For example, it may fire to report completion of the document processing. The list of events being reported is not fixed, and may be flexibly extended over time.

The unique identifier of the event is provided in the EventID parameter. EventParam contains any parameters accompanying the occurrence. Depending on the type of the component, the exact action it is performing, or the document being processed, one or both may be omitted.

RecipientFound Event (MessageDecryptor Component)

Fires to report a message addressee parameters.

Syntax

typedef struct {
  String IssuerRDN;
  DynamicArray SerialNumber;
  DynamicArray SubjectKeyID;
  bool CertFound;
} TsbxMessageDecryptorRecipientFoundEventParams;
typedef void __fastcall (__closure *TsbxMessageDecryptorRecipientFoundEvent)(System::TObject* Sender, TsbxMessageDecryptorRecipientFoundEventParams *e);
__property TsbxMessageDecryptorRecipientFoundEvent OnRecipientFound = { read=FOnRecipientFound, write=FOnRecipientFound };

Remarks

This event is fired for each addressee the message is encrypted for. It may fire several times in a row if the message is encrypted for more than one recipient.

The IssuerRDN, SerialNumber, and SubjectKeyID parameters to identify the recipient's certificate. CertFound indicates if the specified certificate has been located in Certificates collection. If it wasn't, you might want to look up the certificate manually, and add it to the collection inside the event handler.

Config Settings (MessageDecryptor Component)

The component accepts one or more of the following configuration settings. Configuration settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the component, access to these internal properties is provided through the Config method.

MessageDecryptor Config Settings

Base Config Settings

Trappable Errors (MessageDecryptor Component)

MessageDecryptor Errors