This class aim is to minimize encryption output. More...

#include <VirgilTinyCipher.h>

Public Types
enum	PackageSize { PackageSize_Min = 113, PackageSize_Short_SMS = 120, PackageSize_Long_SMS = 1200 }
	Constants that represents maximum number of bytes in one package. More...

Public Member Functions
Configuration
	VirgilTinyCipher (size_t packageSize=PackageSize_Short_SMS)
	Init cipher with given maximum package size. More...

void	reset ()
	Prepare cipher for the next encryption. More...

Encryption
void	encrypt (const VirgilByteArray &data, const VirgilByteArray &recipientPublicKey)
	Encrypt data with given public key. More...

void	encryptAndSign (const VirgilByteArray &data, const VirgilByteArray &recipientPublicKey, const VirgilByteArray &senderPrivateKey, const VirgilByteArray &senderPrivateKeyPassword=VirgilByteArray())
	Encrypt data with given public key and sign package. More...

size_t	getPackageCount () const
	Return total package count. More...

VirgilByteArray	getPackage (size_t index) const
	Return specific package. More...

Decryption
void	addPackage (const VirgilByteArray &package)
	Add package. More...

bool	isPackagesAccumulated () const
	Define whether all packages was accumulated or not. More...

VirgilByteArray	decrypt (const VirgilByteArray &recipientPrivateKey, const VirgilByteArray &recipientPrivateKeyPassword=VirgilByteArray())
	Decrypt accumulated packages. More...

VirgilByteArray	verifyAndDecrypt (const VirgilByteArray &senderPublicKey, const VirgilByteArray &recipientPrivateKey, const VirgilByteArray &recipientPrivateKeyPassword=VirgilByteArray())
	Verify accumulated packages and then decrypt it. More...

Detailed Description

This class aim is to minimize encryption output.

Motivation: If encrypted data is transmitted over GSM module, it very important that encryption output was as small as possible.

Solution: Throw out crypto agility and transfer minimum public information required for decryption.

Pros

Tiny messages.

Cons

Crypto agility is not included in the message, so encrypted messages should not be stored for long term.

Details: During encryption ciper packs encrypted message and service information to the set of packages, which length is limited by maximim package length.

Restrictions

Currently supported public/private keys:

Curve25519

Minimum package length:

113 bytes

See also: VirgilTinyCipher(size_t packageSize); VirgilTinyCipher::PackageSize

Example - Encrypt: VirgilTinyCipher tinyCipher;
VirgilByteArray data = VirgilByteArrayUtils::stringToBytes("String to be encrypted");
tinyCipher.encrypt(data, recipientPublicKey);
for (size_t i = 0; i < tinyCipher.getPackageCount(); ++i) {
VirgilByteArray package = tinyCipher.getPackage(i);
// Send package to the recipient
}

Example - Encrypt and Sign: VirgilTinyCipher tinyCipher;
VirgilByteArray data = VirgilByteArrayUtils::stringToBytes("String to be encrypted");
tinyCipher.encryptAndSign(data, recipientPublicKey, senderPrivateKey, senderPrivateKeyPassword);
for (size_t i = 0; i < tinyCipher.getPackageCount(); ++i) {
VirgilByteArray package = tinyCipher.getPackage(i);
// Send package to the recipient
}

Example - Decrypt: tinyCipher.addPackage(receivedPackage);
if (tinyCipher.isPackagesAccumulated()) {
decryptedData = tinyCipher.decrypt(recipientPrivateKey, recipientPrivateKeyPassword);
}

Example - Verify and Decrypt: tinyCipher.addPackage(receivedPackage);
if (tinyCipher.isPackagesAccumulated()) {
decryptedData = tinyCipher.verifyAndDecrypt(senderPublicKey, recipientPrivateKey, recipientPrivateKeyPassword);
}

Member Enumeration Documentation

enum virgil::crypto::VirgilTinyCipher::PackageSize

Constants that represents maximum number of bytes in one package.

Note: Text representation is 4/3 bigger, i.e 120 * 4/3 = 160 - for short sms.

Enumerator
PackageSize_Min	Min.
PackageSize_Short_SMS	Short SMS.
PackageSize_Long_SMS	Long SMS.

Constructor & Destructor Documentation

virgil::crypto::VirgilTinyCipher::VirgilTinyCipher ( size_t packageSize = PackageSize_Short_SMS )

explicit

Init cipher with given maximum package size.

Parameters

packageSize - maximum number of bytes in one package

Exceptions

std::logic_error - if given packageSize less then minimum value

See also: VirgilTinyCipher::PackageSize

Member Function Documentation

void virgil::crypto::VirgilTinyCipher::addPackage ( const VirgilByteArray & package )

Add package.

Accumulate packages before decryption.

Parameters

package - package to be accumulated

See also: To determine that all packages are received call function isPackagesAccumulated().

Exceptions

VirgilCryptoException - if given package is malformed

VirgilByteArray virgil::crypto::VirgilTinyCipher::decrypt	(	const VirgilByteArray &	recipientPrivateKey,
		const VirgilByteArray &	recipientPrivateKeyPassword = `VirgilByteArray()`
	)

Decrypt accumulated packages.

Parameters

recipientPrivateKey	- recipient private key
recipientPrivateKeyPassword	- recipient private key password (optional)

Returns: Decrypted data.

Exceptions

VirgilCryptoException	- if public key or private key are not supported
VirgilCryptoException	- if data is malformed

void virgil::crypto::VirgilTinyCipher::encrypt	(	const VirgilByteArray &	data,
		const VirgilByteArray &	recipientPublicKey
	)

Encrypt data with given public key.

Parameters

data	- data to be encrypted
recipientPublicKey	- recipient public key

See also: getPackage()

Exceptions

VirgilCryptoException - if public key is not supported

void virgil::crypto::VirgilTinyCipher::encryptAndSign	(	const VirgilByteArray &	data,
		const VirgilByteArray &	recipientPublicKey,
		const VirgilByteArray &	senderPrivateKey,
		const VirgilByteArray &	senderPrivateKeyPassword = `VirgilByteArray()`
	)

Encrypt data with given public key and sign package.

Parameters

data	- data to be encrypted
recipientPublicKey	- recipient public key
senderPrivateKey	- sender private key
senderPrivateKeyPassword	- sender private key password (optional)

See also: Related links can be found in the encrypt() function description.

Exceptions

VirgilCryptoException	- if public key is not supported
VirgilCryptoException	- if private key is not supported
VirgilCryptoException	- if private key password is wrong

VirgilByteArray virgil::crypto::VirgilTinyCipher::getPackage ( size_t index ) const

Return specific package.

Return package with specific index.

Parameters

index - package index

Note: Packages are available when encryption process is completed.

Exceptions

std::out_of_range - if package with given index is not exists

size_t virgil::crypto::VirgilTinyCipher::getPackageCount ( ) const

Return total package count.

Note: Package count is known when encryption process is completed.

See also: getPackage()

bool virgil::crypto::VirgilTinyCipher::isPackagesAccumulated ( ) const

Define whether all packages was accumulated or not.

Returns: true - if all packages was successfully accumulated, false otherwise

See also: addPackage()

void virgil::crypto::VirgilTinyCipher::reset ( )

Prepare cipher for the next encryption.

Note: SHOULD be used before the next encryption.

VirgilByteArray virgil::crypto::VirgilTinyCipher::verifyAndDecrypt	(	const VirgilByteArray &	senderPublicKey,
		const VirgilByteArray &	recipientPrivateKey,
		const VirgilByteArray &	recipientPrivateKeyPassword = `VirgilByteArray()`
	)

Verify accumulated packages and then decrypt it.

Parameters

senderPublicKey	- sender public key
recipientPrivateKey	- recipient private key
recipientPrivateKeyPassword	- recipient private key password (optional)

Exceptions

VirgilCryptoException	- if public key or private key are not supported
VirgilCryptoException	- if data is malformed

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

include/virgil/crypto/VirgilTinyCipher.h

Public Types

Public Member Functions

Detailed Description

Member Enumeration Documentation

Constructor & Destructor Documentation

Member Function Documentation