Package com.dracoon.sdk.crypto

Class Crypto

java.lang.Object

com.dracoon.sdk.crypto.Crypto

public class Crypto
extends Object

This class is the main class of the Dracoon Crypto Library.

The class provides methods for:
- User key pair generation: generateUserKeyPair
- User key pair check: checkUserKeyPair
- File key generation: generateFileKey
- File key encryption: encryptFileKey
- File key decryption: decryptFileKey
- Cipher creation for file encryption: createFileEncryptionCipher
- Cipher creation for file decryption: createFileDecryptionCipher

Method Summary

Modifier and Type	Method	Description
static boolean	checkUserKeyPair(UserKeyPair userKeyPair, char[] password)	Checks if a user key pair can be unlocked.
static FileDecryptionCipher	createFileDecryptionCipher(PlainFileKey fileKey)	Creates a file decryption cipher.
static FileEncryptionCipher	createFileEncryptionCipher(PlainFileKey fileKey)	Creates a file encryption cipher.
static PlainFileKey	decryptFileKey(EncryptedFileKey encFileKey, UserPrivateKey userPrivateKey, char[] password)	Decrypts a file key.
static EncryptedFileKey	encryptFileKey(PlainFileKey plainFileKey, UserPublicKey userPublicKey)	Encrypts a file key.
static PlainFileKey	generateFileKey(PlainFileKey.Version version)	Generates a random file key. IMPORTANT!!!: Never reuse the returned file key! Use the returned file key only for the encryption of one file! The file key consists of a cryptographic key and initialization vector.
static UserKeyPair	generateUserKeyPair(UserKeyPair.Version version, char[] password)	Generates a random user key pair.

Methods inherited from class java.lang.Object

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

Method Details

generateUserKeyPair

public static UserKeyPair generateUserKeyPair(UserKeyPair.Version version,
 char[] password)
                                       throws IllegalArgumentException,
InvalidKeyPairException,
InvalidPasswordException,
CryptoSystemException

Generates a random user key pair.

Parameters:

version - The version for which the key pair should be created.

password - The password which should be used to secure the private key.

Returns:

The generated user key pair.

Throws:

IllegalArgumentException - If a parameter is invalid (e.g. null).

InvalidKeyPairException - If the version for the user key pair is not supported.

InvalidPasswordException - If the password to secure the private key is invalid.

CryptoSystemException - If a unknown error occurred.

checkUserKeyPair

public static boolean checkUserKeyPair(UserKeyPair userKeyPair,
 char[] password)
                                throws InvalidKeyPairException,
CryptoSystemException

Checks if a user key pair can be unlocked.

Parameters:

userKeyPair - The user key pair which should be unlocked.

password - The password which secures the private key.

Returns:

True if the user key pair could be unlocked. Otherwise false.

Throws:

IllegalArgumentException - If a parameter is invalid (e.g. null).

InvalidKeyPairException - If the user key pair is invalid.

CryptoSystemException - If a unknown error occurred.

encryptFileKey

public static EncryptedFileKey encryptFileKey(PlainFileKey plainFileKey,
 UserPublicKey userPublicKey)
                                       throws InvalidFileKeyException,
InvalidKeyPairException,
CryptoSystemException

Encrypts a file key.

Parameters:

plainFileKey - The file key to encrypt.

userPublicKey - The public key which should be used at the encryption.

Returns:

The encrypted file key.

Throws:

IllegalArgumentException - If a parameter is invalid (e.g. null).

InvalidFileKeyException - If the provided plain file key is invalid.

InvalidKeyPairException - If the provided public key is invalid.

CryptoSystemException - If a unknown error occurred.

decryptFileKey

public static PlainFileKey decryptFileKey(EncryptedFileKey encFileKey,
 UserPrivateKey userPrivateKey,
 char[] password)
                                   throws InvalidFileKeyException,
InvalidKeyPairException,
InvalidPasswordException,
CryptoSystemException

Decrypts a file key.

Parameters:

encFileKey - The file key to decrypt.

userPrivateKey - The private key which should be used at the decryption.

password - The password which secures the private key.

Returns:

The decrypted file key.

Throws:

IllegalArgumentException - If a parameter is invalid (e.g. null).

InvalidFileKeyException - If the provided encrypted file key is invalid.

InvalidKeyPairException - If the provided private key is invalid.

InvalidPasswordException - If the provided private key password is invalid.

CryptoSystemException - If a unknown error occurred.

generateFileKey

public static PlainFileKey generateFileKey(PlainFileKey.Version version)

Generates a random file key.

IMPORTANT!!!: Never reuse the returned file key! Use the returned file key only for the encryption of one file!

The file key consists of a cryptographic key and initialization vector. If you reuse both, you compromise the privacy of the encrypted file!

Parameters:

version - The encryption version for which the file key should be created.

Returns:

The generated file key.

Throws:

IllegalArgumentException - If a parameter is invalid (e.g. null).

createFileEncryptionCipher

public static FileEncryptionCipher createFileEncryptionCipher(PlainFileKey fileKey)
                                                       throws CryptoSystemException

Creates a file encryption cipher.

Parameters:

fileKey - The file key which should be used at the encryption.

Returns:

The file encryption cipher.

Throws:

IllegalArgumentException - If a parameter is invalid (e.g. null).

CryptoSystemException - If a unknown error occurred.

createFileDecryptionCipher

public static FileDecryptionCipher createFileDecryptionCipher(PlainFileKey fileKey)
                                                       throws CryptoSystemException

Creates a file decryption cipher.

Parameters:

fileKey - The file key which should be used at the decryption.

Returns:

The file decryption cipher.

Throws:

IllegalArgumentException - If a parameter is invalid (e.g. null).

CryptoSystemException - If a unknown error occurred.