DAMessage Class Reference

Encapsulates a message and various (optional) crypto parameters. More...

#include <DigitalAuthenticationFramework.h>

List of all members.

Public Member Functions
	DAMessage ()
	Constructor Creates an empty message with all zero-length entries.
bool	getMechanism (DAMechanism &mech) const
	Return cryptographic mechanism identifier.
bool	getIV (DAData &iv) const
	Return IV.
bool	getPlaintext (DAData &data) const
	Get the original plaintext/signed message.
bool	getCiphertext (DAData &data) const
	Get the final encrypted message or signature.
DADigestType	getDigestType () const
	Gets digest (hash) type used for signature.
void	setMechanism (const DAMechanism &mech)
	Set Crypto Algorithm.
bool	setMechanismForRSAPkcs1Signature ()
	Set mechanism appropriately for RSA-SSA-PKCS1 signatures.
bool	setMechanismForDSA ()
	Set mechanism appropriately for DSA algorithm.
bool	setMechanismForECDSA ()
	Set mechanism appropriately for ECDSA algorithm.
void	setIV (const DAData &iv)
	Set IV.
void	setPlaintext (const DAData &data)
	Set plaintext buffer.
void	setCiphertext (const DAData &data)
	Set ciphertext buffer.
void	setDigestType (DADigestType dtype)
	Set digest type.
void	unsetMechanism ()
	Remove Crypto Algorithm.
void	unsetIV ()
	Remove IV.
void	unsetPlaintext ()
	Remove plaintext.
void	unsetCiphertext ()
	Remove ciphertext.
void	unsetDigestType ()
	Unset digestType.
bool	applyDefaultDigest ()
	Ensure a DAMessage contains a message hash for signature.
bool	getPkcs1SignatureData (DAData &msg)
	Create a byte string suitable for RSA PKCS#1 signature.
Static Public Member Functions
static DADigestType	getDigestFromMech (const DAMechanism &mech)
	Get hash type associated with a mechanism.
Protected Types
enum	{ HAVE_PLAINTEXT = 1, HAVE_CIPHERTEXT = 2, HAVE_IV = 4, HAVE_MECH = 8 }
Protected Attributes
DAData	m_plaintext
	Plaintext bytes.
DAData	m_ciphertext
	Ciphertext bytes.
DAData	m_iv
	IV bytes.
DAMechanism	m_mech
	Mechanism (OID)
unsigned	m_flags
	Flags (HAVE_PLAINTEXT etc)
DADigestType	m_digestType
	Digest used for signed message.

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Detailed Description

Encapsulates a message and various (optional) crypto parameters.

Keys operate on Messages.

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Member Enumeration Documentation

anonymous enum [protected]

Enumerator:

HAVE_PLAINTEXT	m_plaintext has been set
HAVE_CIPHERTEXT	m_ciphertext has been set
HAVE_IV	m_iv has been set
HAVE_MECH	m_mech has been set

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Member Function Documentation

bool DAMessage::applyDefaultDigest

(

)

Ensure a DAMessage contains a message hash for signature.

If the digest type (see getDigestType()) is not DA_DIGEST_NONE, leaves the message unchanged, and returns true.

Otherwise, if the mechanism (see getMechanism()) has already been set, applies the hash algorithm appropriate to that mechanism. The message's plaintext field is replaced by the hash, and the digest type is set accordingly. This method will return true if the operation succeeded, and false if the mechanism was not recognised.

If the mechanism was not set, a default hash algorithm is chosen (in this release, SHA-256). The plaintext is replaced by its hash, and the digest type field is set (to DA_DIGEST_SHA256). The method then returns true.

Returns:

true if operation succeeded, false if the mechanism was set on entry but not for a supported hash type.

static DADigestType DAMessage::getDigestFromMech

(

const DAMechanism &

mech

)

[static]

Get hash type associated with a mechanism.

Parameters:

mech	Specifier for an (asymmetric) signature mechanism

Returns:

Digest type associated with this mechanism, or DA_DIGEST_NONE if it's unrecognised.

DADigestType DAMessage::getDigestType

(

)

const [inline]

Gets digest (hash) type used for signature.

Returns:

DA_DIGEST_NONE if message is not hashed

bool DAMessage::getMechanism

(

DAMechanism &

mech

)

const [inline]

Return cryptographic mechanism identifier.

This is, in most cases, a value chosen from class CommonMech. It is set by the DAKey::sign() and DAKey::encrypt() methods, and must be set by the called before DAKey::verify() and DAKey::decrypt().

Returns:

true if a mechanism was set (and mech had a value assigned). Returns false if no mechanism is set.

bool DAMessage::getPkcs1SignatureData

(

DAData &

msg

)

Create a byte string suitable for RSA PKCS#1 signature.

Parameters:

msg	Byte-block returned. This is the DER encoding of a SEQUENCE containing the OID of the hash function followed by the hash value. See e.g. RFC 3447 section 9.2. This function will also apply a default hash function if the message doesn't have a digest type set.

Returns:

true if operation succeeded, false if the DAMessage is invalid/unsuitable.

bool DAMessage::setMechanismForDSA

(

)

Set mechanism appropriately for DSA algorithm.

Chooses a suitable DAMechanism (see common_mechs.h) for the hash algorithm identified by the m_digestType field, and sets it as the m_mech field.

Returns:

false if invalid mechanism in m_digestType.

bool DAMessage::setMechanismForECDSA

(

)

Set mechanism appropriately for ECDSA algorithm.

Chooses a suitable DAMechanism (see common_mechs.h) for the hash algorithm identified by the m_digestType field, and sets it as the m_mech field.

Returns:

false if invalid mechanism in m_digestType.

bool DAMessage::setMechanismForRSAPkcs1Signature

(

)

Set mechanism appropriately for RSA-SSA-PKCS1 signatures.

Chooses a suitable DAMechanism (see common_mechs.h) for the hash algorithm identified by the m_digestType field, and sets it as the m_mech field.

Returns:

false if invalid mechanism in m_digestType.

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The documentation for this class was generated from the following file:

• DigitalAuthenticationFramework.h