QCA::PublicKey Class Reference

#include <QtCrypto>

Inheritance diagram for QCA::PublicKey:

Public Member Functions
	PublicKey ()
	PublicKey (const PrivateKey &k)
	PublicKey (const PublicKey &from)
	PublicKey (const QString &fileName)
bool	canDecrypt () const
bool	canEncrypt () const
bool	canVerify () const
bool	decrypt (const SecureArray &in, SecureArray *out, EncryptionAlgorithm alg)
SecureArray	encrypt (const SecureArray &a, EncryptionAlgorithm alg)
int	maximumEncryptSize (EncryptionAlgorithm alg) const
PublicKey &	operator= (const PublicKey &from)
void	startVerify (SignatureAlgorithm alg, SignatureFormat format=DefaultFormat)
QByteArray	toDER () const
DHPublicKey	toDH () const
DSAPublicKey	toDSA () const
QString	toPEM () const
bool	toPEMFile (const QString &fileName) const
RSAPublicKey	toRSA () const
void	update (const MemoryRegion &a)
bool	validSignature (const QByteArray &sig)
bool	verifyMessage (const MemoryRegion &a, const QByteArray &sig, SignatureAlgorithm alg, SignatureFormat format=DefaultFormat)
Public Member Functions inherited from QCA::PKey
	PKey ()
	PKey (const PKey &from)
int	bitSize () const
bool	canExport () const
bool	canKeyAgree () const
bool	isDH () const
bool	isDSA () const
bool	isNull () const
bool	isPrivate () const
bool	isPublic () const
bool	isRSA () const
bool	operator!= (const PKey &a) const
PKey &	operator= (const PKey &from)
bool	operator== (const PKey &a) const
PrivateKey	toPrivateKey () const
PublicKey	toPublicKey () const
Type	type () const
Public Member Functions inherited from QCA::Algorithm
	Algorithm (const Algorithm &from)
void	change (const QString &type, const QString &provider)
void	change (Provider::Context *c)
Provider::Context *	context ()
const Provider::Context *	context () const
Algorithm &	operator= (const Algorithm &from)
Provider *	provider () const
Provider::Context *	takeContext ()
QString	type () const

Static Public Member Functions
static PublicKey	fromDER (const QByteArray &a, ConvertResult *result=nullptr, const QString &provider=QString())
static PublicKey	fromPEM (const QString &s, ConvertResult *result=nullptr, const QString &provider=QString())
static PublicKey	fromPEMFile (const QString &fileName, ConvertResult *result=nullptr, const QString &provider=QString())
Static Public Member Functions inherited from QCA::PKey
static QList< Type >	supportedIOTypes (const QString &provider=QString())
static QList< Type >	supportedTypes (const QString &provider=QString())

Protected Member Functions
	PublicKey (const QString &type, const QString &provider)
Protected Member Functions inherited from QCA::PKey
	PKey (const QString &type, const QString &provider)
void	set (const PKey &k)
DHPrivateKey	toDHPrivateKey () const
DHPublicKey	toDHPublicKey () const
DSAPrivateKey	toDSAPrivateKey () const
DSAPublicKey	toDSAPublicKey () const
RSAPrivateKey	toRSAPrivateKey () const
RSAPublicKey	toRSAPublicKey () const
Protected Member Functions inherited from QCA::Algorithm
	Algorithm ()
	Algorithm (const QString &type, const QString &provider)

Additional Inherited Members
Public Types inherited from QCA::PKey
enum	Type { RSA , DSA , DH }

Detailed Description

Generic public key.

Examples

rsatest.cpp.

Definition at line 528 of file qca_publickey.h.

Constructor & Destructor Documentation

PublicKey() [1/5]

QCA::PublicKey::PublicKey

(

)

Create an empty (null) public key.

PublicKey() [2/5]

QCA::PublicKey::PublicKey

(

const PrivateKey &

k

)

Create a public key based on a specified private key.

Parameters

k	the private key to extract the public key parts from

PublicKey() [3/5]

QCA::PublicKey::PublicKey

(

const QString &

fileName

)

Import a public key from a PEM representation in a file.

Parameters

fileName

the name of the file containing the public key

See also

fromPEMFile for an alternative method

PublicKey() [4/5]

QCA::PublicKey::PublicKey

(

const PublicKey &

from

)

Copy constructor.

Parameters

from	the PublicKey to copy from

PublicKey() [5/5]

QCA::PublicKey::PublicKey ( const QString & type, const QString & provider )

protected

Create a new key of a specified type.

Parameters

type	the type of key to create
provider	the provider to use, if required

Member Function Documentation

canDecrypt()

bool QCA::PublicKey::canDecrypt

(

)

const

Test if this key can be used for decryption.

Returns

true if the key can be used for decryption

canEncrypt()

bool QCA::PublicKey::canEncrypt

(

)

const

Test if this key can be used for encryption.

Returns

true if the key can be used for encryption

Examples

rsatest.cpp.

canVerify()

bool QCA::PublicKey::canVerify

(

)

const

Test if the key can be used for verifying signatures.

Returns

true of the key can be used for verification

Examples

rsatest.cpp.

decrypt()

bool QCA::PublicKey::decrypt	(	const SecureArray &	in,
		SecureArray *	out,
		EncryptionAlgorithm	alg )

Decrypt the message.

Parameters

in	the cipher (encrypted) data
out	the plain text data
alg	the algorithm to use

Note

This synchronous operation may require event handling, and so it must not be called from the same thread as an EventHandler.

encrypt()

SecureArray QCA::PublicKey::encrypt	(	const SecureArray &	a,
		EncryptionAlgorithm	alg )

Encrypt a message using a specified algorithm.

Parameters

a	the message to encrypt
alg	the algorithm to use

Examples

rsatest.cpp.

fromDER()

static PublicKey QCA::PublicKey::fromDER ( const QByteArray & a, ConvertResult * result = nullptr, const QString & provider = QString() )

static

Import a key in Distinguished Encoding Rules (DER) format.

This function takes a binary array, which is assumed to contain a public key in DER encoding, and returns the key. Unless you don't care whether the import succeeded, you should test the result, as shown below.

QCA::ConvertResult conversionResult;
QCA::PublicKey publicKey = QCA::PublicKey::fromDER(keyArray, &conversionResult);
if (! QCA::ConvertGood == conversionResult)
{
    std::cout << "Public key read failed" << std::endl;
}

Parameters

a	the array containing a DER encoded key
result	pointer to a variable, which returns whether the conversion succeeded (ConvertGood) or not
provider	the name of the provider to use for the import.

fromPEM()

static PublicKey QCA::PublicKey::fromPEM ( const QString & s, ConvertResult * result = nullptr, const QString & provider = QString() )

static

Import a key in Privacy Enhanced Mail (PEM) format.

This function takes a string, which is assumed to contain a public key in PEM encoding, and returns that key. Unless you don't care whether the import succeeded, you should test the result, as shown below.

QCA::ConvertResult conversionResult;
QCA::PublicKey publicKey = QCA::PublicKey::fromPEM(keyAsString, &conversionResult);
if (! QCA::ConvertGood == conversionResult)
{
    std::cout << "Public key read failed" << std::endl;
}

Parameters

s	the string containing a PEM encoded key
result	pointer to a variable, which returns whether the conversion succeeded (ConvertGood) or not
provider	the name of the provider to use for the import.

See also

toPEM, which provides an inverse of fromPEM()

fromPEMFile, which provides an import direct from a file.

fromPEMFile()

static PublicKey QCA::PublicKey::fromPEMFile ( const QString & fileName, ConvertResult * result = nullptr, const QString & provider = QString() )

static

Import a key in Privacy Enhanced Mail (PEM) format from a file.

This function takes the name of a file, which is assumed to contain a public key in PEM encoding, and returns that key. Unless you don't care whether the import succeeded, you should test the result, as shown below.

QCA::ConvertResult conversionResult;
QCA::PublicKey publicKey = QCA::PublicKey::fromPEMFile(fileName, &conversionResult);
if (! QCA::ConvertGood == conversionResult)
{
    std::cout << "Public key read failed" << std::endl;
}

Parameters

fileName	a string containing the name of the file
result	pointer to a variable, which returns whether the conversion succeeded (ConvertGood) or not
provider	the name of the provider to use for the import.

See also

toPEMFile, which provides an inverse of fromPEMFile()

fromPEM, which provides an import from a string

Note

there is also a constructor form that can import from a file

maximumEncryptSize()

int QCA::PublicKey::maximumEncryptSize

(

EncryptionAlgorithm

alg

)

const

The maximum message size that can be encrypted with a specified algorithm.

Parameters

alg	the algorithm to check

operator=()

PublicKey & QCA::PublicKey::operator=

(

const PublicKey &

from

)

Assignment operator.

Parameters

from	the PublicKey to copy from

startVerify()

void QCA::PublicKey::startVerify	(	SignatureAlgorithm	alg,
		SignatureFormat	format = DefaultFormat )

Initialise the signature verification process.

Parameters

alg	the algorithm to use for signing
format	the specific format to use, for DSA

Examples

rsatest.cpp.

toDER()

QByteArray QCA::PublicKey::toDER

(

)

const

Export the key in Distinguished Encoding Rules (DER) format.

toDH()

DHPublicKey QCA::PublicKey::toDH

(

)

const

Convenience method to convert this key to a DHPublicKey.

Note that if the key is not an DH key (eg it is DSA or RSA), then this will produce a null key.

toDSA()

DSAPublicKey QCA::PublicKey::toDSA

(

)

const

Convenience method to convert this key to a DSAPublicKey.

Note that if the key is not an DSA key (eg it is RSA or DH), then this will produce a null key.

toPEM()

QString QCA::PublicKey::toPEM

(

)

const

Export the key in Privacy Enhanced Mail (PEM) format.

See also

toPEMFile provides a convenient way to save the PEM encoded key to a file

fromPEM provides an inverse of toPEM, converting the PEM encoded key back to a PublicKey

toPEMFile()

bool QCA::PublicKey::toPEMFile

(

const QString &

fileName

)

const

Export the key in Privacy Enhanced Mail (PEM) to a file.

Parameters

fileName

the name (and path, if necessary) of the file to save the PEM encoded key to.

See also

toPEM for a version that exports to a QString, which may be useful if you need to do more sophisticated handling

fromPEMFile provides an inverse of toPEMFile, reading a PEM encoded key from a file

toRSA()

RSAPublicKey QCA::PublicKey::toRSA

(

)

const

Convenience method to convert this key to an RSAPublicKey.

Note that if the key is not an RSA key (eg it is DSA or DH), then this will produce a null key.

update()

void QCA::PublicKey::update

(

const MemoryRegion &

a

)

Update the signature verification process with more data.

Parameters

a	the array containing the data that should be added to the signature

Examples

rsatest.cpp.

validSignature()

bool QCA::PublicKey::validSignature

(

const QByteArray &

sig

)

Check the signature is valid for the message.

The process to check that a signature is correct is shown below:

// note that pubkey is a PublicKey
if( pubkey.canVerify() )
{
    pubkey.startVerify( QCA::EMSA3_MD5 );
    pubkey.update( theMessage ); // might be called multiple times
    if ( pubkey.validSignature( theSignature ) )
    {
        // then signature is valid
    }
    else
    {
        // then signature is invalid
    }
}

Parameters

sig	the signature to check

Returns

true if the signature is correct

Examples

rsatest.cpp.

verifyMessage()

bool QCA::PublicKey::verifyMessage	(	const MemoryRegion &	a,
		const QByteArray &	sig,
		SignatureAlgorithm	alg,
		SignatureFormat	format = DefaultFormat )

Single step message verification.

If you have the whole message to be verified, then this offers a more convenient approach to verification.

Parameters

a	the message to check the signature on
sig	the signature to be checked
alg	the algorithm to use
format	the signature format to use, for DSA

Returns

true if the signature is valid for the message

Examples

rsatest.cpp.

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

• qca_publickey.h