iaik.smime.ess
Class ContentHints

java.lang.Object
  iaik.asn1.structures.AttributeValue
      iaik.smime.ess.ESSAttributeValue
          iaik.smime.ess.ContentHints

All Implemented Interfaces:

ASN1Type

public class ContentHints
extends ESSAttributeValue

The S/MIMEv3 ESS ContentHints attribute.

The Enhanced Security Services for S/MIMEv3 (ESS) (RFC 2634) specifies the ContentHints attribute to may be included as an attribute in a SignerInfo to provide information describing the innermost signed content of a multi-layer message at the outermost signature layer.

 ContentHints ::= SEQUENCE {
   contentDescription UTF8String (SIZE (1..MAX)) OPTIONAL,
   contentType ContentType }

 id-aa-contentHint OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840)
     rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) id-aa(2) 4}
 

The contentDescription field may be used to provide information that the recipient may use to select protected messages for processing, such as a message subject. If this field is set, then the attribute is expected to appear on the signedData object enclosing an envelopedData object and not on the inner signedData object. The (SIZE (1..MAX)) construct constrains the sequence to have at least one entry. MAX indicates the upper bound is unspecified. Implementations are free to choose an upper bound that suits their environment.
Messages which contain a signedData object wrapped around an envelopedData object, thus masking the inner content type of the message, SHOULD include a contentHints attribute, except for the case of the data content type. Specific message content types may either force or preclude the inclusion of the contentHints attribute. For example, when a signedData/Receipt is encrypted within an envelopedData object, an outer signedData object MUST be created that encapsulates the envelopedData object and a contentHints attribute with contentType set to the id-ct-receipt object identifier MUST be included in the outer signedData SignerInfo signedAttributes.

When creating a ContentHints object the content type object identifier has to be supplied. Subsequently method setContentDescription may be called to provide a string describing the content:

 ObjectID contentType = ...;
 String contentDescription = ...;
 ContentHints contentHints = new ContentHints(contentType);
 contentHints.setContentDescription(contentDescription);
 

Field Summary

static ObjectID

oid The attributeType object identifier of this ContentHints attribute.

Constructor Summary

ContentHints()
Empty default constructor.

ContentHints(ASN1Object obj)
Creates an ContentHints from its ASN.1 representation.

ContentHints(ObjectID contentType)
Creates an ContentHints for the given content type.

Method Summary

void	decode(ASN1Object obj) Decodes the given ASN.1 ContentHints object for parsing the internal structure.
boolean	equals(java.lang.Object obj) Compares this ContentHints to the specified object.
ObjectID	getAttributeType() Returns the OID identifying the ContentHints attribute type.
java.lang.String	getContentDescription() Returns the (first) content description, if included.
java.lang.String[]	getContentDescriptions() Returns the (first) content description, if included.
ObjectID	getContentType() Returns the content type.
int	hashCode() Returns a hashcode for this ContentHints.
void	setContentDescription(java.lang.String contentDescription) Sets the content description.
void	setContentDescriptions(java.lang.String[] contentDescriptions) Sets the content descriptions (if more than one content description is used).
static void	setMaxNumOfContentDescriptions(int max) Sets the allowed number of content description fields.
ASN1Object	toASN1Object() Returns this ContentHints as ASN1Object.
java.lang.String	toString() Returns a string representation of this ContentHints.

Methods inherited from class iaik.smime.ess.ESSAttributeValue

multipleAllowed

Methods inherited from class iaik.asn1.structures.AttributeValue

getName

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

oid

public static final ObjectID oid

The attributeType object identifier of this ContentHints attribute. The corresponding OID string is "1.2.840.113549.1.9.16.2.4".

Constructor Detail

ContentHints

public ContentHints()

Empty default constructor. Required for dynamic object creation. Shall NOT be used by an application.

ContentHints

public ContentHints(ObjectID contentType)

Creates an ContentHints for the given content type.

Parameters:

contentType - the content type

ContentHints

public ContentHints(ASN1Object obj)
             throws CodingException

Creates an ContentHints from its ASN.1 representation.

Parameters:

obj - the ContentHints as ASN1Object

Throws:

CodingException - if the encoding is invalid

Method Detail

setMaxNumOfContentDescriptions

public static void setMaxNumOfContentDescriptions(int max)

Sets the allowed number of content description fields.

Parameters:

max - the max number of content description fields (default: 1).

getContentType

public ObjectID getContentType()

Returns the content type.

Returns:

the type of the content

setContentDescription

public void setContentDescription(java.lang.String contentDescription)

Sets the content description.

The contentDescription field may be used to provide information that the recipient may use to select protected messages for processing, such as a message subject. If this field is set, then the ContentHints attribute is expected to appear on the signedData object enclosing an envelopedData object and not on the inner signedData object.

Parameters:

contentDescription - a string describing the content

setContentDescriptions

public void setContentDescriptions(java.lang.String[] contentDescriptions)

Sets the content descriptions (if more than one content description is used).

The contentDescription field may be used to provide information that the recipient may use to select protected messages for processing, such as a message subject. If this field is set, then the ContentHints attribute is expected to appear on the signedData object enclosing an envelopedData object and not on the inner signedData object.

Parameters:

contentDescriptions - the content description terms to be set

Throws:

java.lang.IllegalArgumentException - if the number of content description terms exceeds the maximum allowed number setMaxNumOfContentDescriptions of content description terms or any of the array elements is null

getContentDescription

public java.lang.String getContentDescription()

Returns the (first) content description, if included.

The contentDescription field may be used to provide information that the recipient may use to select protected messages for processing, such as a message subject. If this field is set, then the ContentHints attribute is expected to appear on the signedData object enclosing an envelopedData object and not on the inner signedData object.

Returns:

a string describing the content, or null if no ContentDescription is included

getContentDescriptions

public java.lang.String[] getContentDescriptions()

Returns the (first) content description, if included.

The contentDescription field may be used to provide information that the recipient may use to select protected messages for processing, such as a message subject. If this field is set, then the ContentHints attribute is expected to appear on the signedData object enclosing an envelopedData object and not on the inner signedData object.

Returns:

a string describing the content, or null if no ContentDescription is included

decode

public void decode(ASN1Object obj)
            throws CodingException

Decodes the given ASN.1 ContentHints object for parsing the internal structure.

Parameters:

obj - the ContentHints as ASN1Object

Throws:

CodingException - if the encoding is invalid

toASN1Object

public ASN1Object toASN1Object()

Returns this ContentHints as ASN1Object.

Returns:

this ContentHints as ASN1Object

getAttributeType

public ObjectID getAttributeType()

Returns the OID identifying the ContentHints attribute type.

Specified by:

getAttributeType in class AttributeValue

Returns:

the OID identifying the ContentHints attribute type.

equals

public boolean equals(java.lang.Object obj)

Compares this ContentHints to the specified object.

Specified by:

equals in class ESSAttributeValue

Parameters:

obj - the object to compare this ContentHints against.

Returns:

true, if the given object is equal to this ContentHints, false otherwise

hashCode

public int hashCode()

Returns a hashcode for this ContentHints.

Overrides:

hashCode in class ESSAttributeValue

Returns:

a hashcode calculated for this ContentHints

toString

public java.lang.String toString()

Returns a string representation of this ContentHints.

Specified by:

toString in class AttributeValue

Returns:

this ContentHints as string