COSE

Class SignMessage

java.lang.Object

COSE.Attribute

COSE.Message

COSE.SignMessage

public class SignMessage
extends Message

The SignMessage class is used to implement the COSE_Sign object. This provides for a signed object with content and one or more signatures attached. The signatures can be either from a single signer or from multiple different signers. In the case where only one signature is required and the signer can be implicitly known, Sign1Message can be used instead. There is no way to convert a signed message between the two formats.

Create a SignMessage object for a new message, when processing an existing message use Message.DecodeFromBytes to create a SignMessage object.

Examples can be found at
Single Signer Example an example of signing and verify a message with a single signature.
Multiple Signer Example an example of signing and verifying a message which has multiple signatures.

Author:

jimsch

Field Summary

Fields

Modifier and Type	Field and Description
protected List<Signer>	signerList

Fields inherited from class COSE.Message

emitContent, emitTag, messageTag, rgbContent

Fields inherited from class COSE.Attribute

DO_NOT_SEND, DontSendAttributes, externalData, objDontSend, objProtected, objUnprotected, PROTECTED, ProtectedAttributes, rgbProtected, UNPROTECTED, UnprotectedAttributes

Constructor Summary

Constructors

Constructor and Description
SignMessage() Create a signed message object for which the leading tag and the content will be included.
SignMessage(boolean emitTagIn, boolean emitContentIn) Create a signed message object for which the emission of the leading tag and content is controlled by the parameters.

Method Summary

Modifier and Type	Method and Description
void	AddSigner(Signer signedBy) Add a new signer to the message.
protected void	DecodeFromCBORObject(com.upokecenter.cbor.CBORObject obj) Internal function used in creating a SignMessage object from a byte string.
protected com.upokecenter.cbor.CBORObject	EncodeCBORObject() Internal function used to create a serialization of a COSE_Sign message
Signer	getSigner(int iSigner) Return the i-th signer of the message.
int	getSignerCount() Return the number of signers on the message
List<Signer>	getSignerList() Return the list of signers on the message
void	sign() Causes a signature to be created for every signer that does not already have one.
boolean	validate(Signer signerToUse) Validate the signature on a message for a specific signer.

Methods inherited from class COSE.Message

DecodeFromBytes, DecodeFromBytes, EncodeToBytes, EncodeToCBORObject, GetContent, HasContent, SetContent, SetContent

Methods inherited from class COSE.Attribute

addAttribute, addAttribute, addAttribute, AddProtected, AddProtected, AddProtected, AddUnprotected, AddUnprotected, AddUnprotected, findAttribute, findAttribute, findAttribute, findAttribute, getDoNotSendAttributes, getExternal, getProtectedAttributes, getUnprotectedAttributes, removeAttribute, removeAttribute, setExternal

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

signerList

protected List<Signer> signerList

Constructor Detail

SignMessage

public SignMessage()

Create a signed message object for which the leading tag and the content will be included.

SignMessage

public SignMessage(boolean emitTagIn,
                   boolean emitContentIn)

Create a signed message object for which the emission of the leading tag and content is controlled by the parameters.

Parameters:

emitTagIn - emit leading tag when message is serialized

emitContentIn - emit the content as part of the message

Method Detail

DecodeFromCBORObject

protected void DecodeFromCBORObject(com.upokecenter.cbor.CBORObject obj)
                             throws CoseException

Internal function used in creating a SignMessage object from a byte string.

Specified by:

DecodeFromCBORObject in class Message

Parameters:

obj - COSE_Sign encoded object.

Throws:

CoseException - Errors generated by the COSE module

EncodeCBORObject

protected com.upokecenter.cbor.CBORObject EncodeCBORObject()
                                                    throws CoseException

Internal function used to create a serialization of a COSE_Sign message

Specified by:

EncodeCBORObject in class Message

Returns:

CBOR object which can be encoded.

Throws:

CoseException - Errors generated by the COSE module

AddSigner

public void AddSigner(Signer signedBy)

Add a new signer to the message. The details of the signer are provided by the Signer object being added.

Parameters:

signedBy - provides a Signer object containing details for the signer

getSigner

public Signer getSigner(int iSigner)

Return the i-th signer of the message.

Parameters:

iSigner - - which signer to be returned

Returns:

Signer object

getSignerCount

public int getSignerCount()

Return the number of signers on the message

Returns:

number of elements in the signer list

getSignerList

public List<Signer> getSignerList()

Return the list of signers on the message

Returns:

a list of all of the Signer objects.

sign

public void sign()
          throws CoseException

Causes a signature to be created for every signer that does not already have one.

Throws:

CoseException - Errors generated by the COSE module

validate

public boolean validate(Signer signerToUse)
                 throws CoseException

Validate the signature on a message for a specific signer. The signer is required to be one of the Signer objects attached to the message. The key must be attached to the signer before making this call.

Parameters:

signerToUse - which signer to validate with

Returns:

true if the message validates with the signer

Throws:

CoseException - Errors generated by the COSE module