com.amazonaws.encryptionsdk.internal

Class EncryptionHandler

java.lang.Object

com.amazonaws.encryptionsdk.internal.EncryptionHandler

All Implemented Interfaces:

CryptoHandler, MessageCryptoHandler

public class EncryptionHandler
extends Object
implements MessageCryptoHandler

This class implements the CryptoHandler interface by providing methods for the encryption of plaintext data.

This class creates the ciphertext headers and delegates the encryption of the plaintext to the BlockEncryptionHandler or FrameEncryptionHandler based on the content type.

Constructor Summary

Constructors

Constructor and Description
EncryptionHandler(int frameSize, EncryptionMaterials result, CommitmentPolicy commitmentPolicy) Create an encryption handler using the provided master key and encryption context.

Method Summary

Modifier and Type	Method and Description
int	doFinal(byte[] out, int outOff) Finish encryption of the plaintext bytes.
int	estimateFinalOutputSize() Return the size of the output buffer required for a call to CryptoHandler.doFinal(byte[], int).
int	estimateOutputSize(int inLen) Return the size of the output buffer required for a processBytes plus a doFinal with an input of inLen bytes.
int	estimatePartialOutputSize(int inLen) Return the size of the output buffer required for a call to CryptoHandler.processBytes(byte[], int, int, byte[], int).
Map<String,String>	getEncryptionContext() Return the encryption context.
CiphertextHeaders	getHeaders()
List<? extends MasterKey<?>>	getMasterKeys() All used MasterKeys.
boolean	isComplete() For decrypt and parsing flows returns true when this has handled as many bytes as it can.
ProcessingSummary	processBytes(byte[] in, int off, int len, byte[] out, int outOff) Encrypt a block of bytes from in putting the plaintext result into out.
void	setMaxInputLength(long size) Informs this handler of an upper bound on the input data size.

Methods inherited from class java.lang.Object

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

Constructor Detail

EncryptionHandler

public EncryptionHandler(int frameSize,
                         EncryptionMaterials result,
                         CommitmentPolicy commitmentPolicy)
                  throws AwsCryptoException

Create an encryption handler using the provided master key and encryption context.

Parameters:

frameSize - The encryption frame size, or zero for a one-shot encryption task

result - The EncryptionMaterials with the crypto materials for this encryption job

Throws:

AwsCryptoException - if the encryption context or master key is null.

Method Detail

processBytes

public ProcessingSummary processBytes(byte[] in,
                                      int off,
                                      int len,
                                      byte[] out,
                                      int outOff)
                               throws AwsCryptoException,
                                      BadCiphertextException

Encrypt a block of bytes from in putting the plaintext result into out.

It encrypts by performing the following operations:

1. if this is the first call to encrypt, write the ciphertext headers to the output being returned.
2. else, pass off the input data to underlying content cryptohandler.

Specified by:

processBytes in interface CryptoHandler

Parameters:

in - the input byte array.

off - the offset into the in array where the data to be encrypted starts.

len - the number of bytes to be encrypted.

out - the output buffer the encrypted bytes go into.

outOff - the offset into the output byte array the encrypted data starts at.

Returns:

the number of bytes written to out and processed

Throws:

AwsCryptoException - if len or offset values are negative.

BadCiphertextException - thrown by the underlying cipher handler.

doFinal

public int doFinal(byte[] out,
                   int outOff)
            throws BadCiphertextException

Finish encryption of the plaintext bytes.

Specified by:

doFinal in interface CryptoHandler

Parameters:

out - space for any resulting output data.

outOff - offset into out to start copying the data at.

Returns:

number of bytes written into out.

Throws:

BadCiphertextException - thrown by the underlying cipher handler.

estimateOutputSize

public int estimateOutputSize(int inLen)

Return the size of the output buffer required for a processBytes plus a doFinal with an input of inLen bytes.

Specified by:

estimateOutputSize in interface CryptoHandler

Parameters:

inLen - the length of the input.

Returns:

the space required to accommodate a call to processBytes and doFinal with len bytes of input.

estimatePartialOutputSize

public int estimatePartialOutputSize(int inLen)

Description copied from interface: CryptoHandler

Return the size of the output buffer required for a call to CryptoHandler.processBytes(byte[], int, int, byte[], int).

Note this method is allowed to return an estimation of the output size that is greater than the actual size of the output. Returning an estimate that is lesser than the actual size of the output will result in underflow exceptions.

Specified by:

estimatePartialOutputSize in interface CryptoHandler

Parameters:

inLen - the length of the input.

Returns:

the space required to accommodate a call to CryptoHandler.processBytes(byte[], int, int, byte[], int) with an input of size inLen bytes.

estimateFinalOutputSize

public int estimateFinalOutputSize()

Description copied from interface: CryptoHandler

Return the size of the output buffer required for a call to CryptoHandler.doFinal(byte[], int).

Note this method is allowed to return an estimation of the output size that is greater than the actual size of the output. Returning an estimate that is lesser than the actual size of the output will result in underflow exceptions.

Specified by:

estimateFinalOutputSize in interface CryptoHandler

Returns:

the space required to accomodate a call to CryptoHandler.doFinal(byte[], int)

getEncryptionContext

public Map<String,String> getEncryptionContext()

Return the encryption context.

Specified by:

getEncryptionContext in interface MessageCryptoHandler

Returns:

the key-value map containing encryption context.

getHeaders

public CiphertextHeaders getHeaders()

Specified by:

getHeaders in interface MessageCryptoHandler

setMaxInputLength

public void setMaxInputLength(long size)

Description copied from interface: MessageCryptoHandler

Informs this handler of an upper bound on the input data size. The handler will throw an exception if this bound is exceeded, and may use it to perform performance optimizations as well.

If this method is called multiple times, the smallest bound will be used.

Specified by:

setMaxInputLength in interface MessageCryptoHandler

Parameters:

size - An upper bound on the input data size.

getMasterKeys

public List<? extends MasterKey<?>> getMasterKeys()

Description copied from interface: MessageCryptoHandler

All used MasterKeys. For encryption flows, these are all the MasterKeys used to protect the data. In the decryption flow, it is the single MasterKey actually used to decrypt the data.

Specified by:

getMasterKeys in interface MessageCryptoHandler

isComplete

public boolean isComplete()

Description copied from interface: CryptoHandler

For decrypt and parsing flows returns true when this has handled as many bytes as it can. This usually means that it has reached the end of an object, file, or other delimited stream.

Specified by:

isComplete in interface CryptoHandler