com.itextpdf.commons.bouncycastle.crypto.modes

Interface IGCMBlockCipher

public interface IGCMBlockCipher

Interface for aes-gcm cryptographic ciphers.

Method Summary

Modifier and Type	Method and Description
void	doFinal(byte[] plainText, int i) Finishes a multiple-part encryption or decryption operation, depending on how this cipher was initialized.
int	getOutputSize(int len) Returns the length in bytes that an output buffer would need to be in order to hold the result of the next doFinal operation, given the input length (in bytes).
int	getUpdateOutputSize(int len) Returns the length in bytes that an output buffer would need to be in order to hold the result of the next update operation, given the input length (in bytes).
void	init(boolean forEncryption, byte[] key, int macSizeBits, byte[] iv) Initialize this cipher with a key and a set of algorithm parameters.
void	processBytes(byte[] input, int inputOffset, int len, byte[] output, int outOffset) Perform a multiple-part encryption or decryption operation (depending on how this cipher was initialized), processing another data part.

Method Detail

init

void init(boolean forEncryption,
          byte[] key,
          int macSizeBits,
          byte[] iv)
   throws GeneralSecurityException

Initialize this cipher with a key and a set of algorithm parameters.

Parameters:

forEncryption - true to use encrypt mode, false to use decrypt mode

key - the encryption key

macSizeBits - MAC size, MAC sizes from 32 bits to 128 bits (must be a multiple of 8)

iv - the IV source buffer

Throws:

GeneralSecurityException - in case any error during encryption or decryption

getUpdateOutputSize

int getUpdateOutputSize(int len)

Returns the length in bytes that an output buffer would need to be in order to hold the result of the next update operation, given the input length (in bytes).

Parameters:

len - input length (in bytes)

Returns:

output length in bytes

processBytes

void processBytes(byte[] input,
                  int inputOffset,
                  int len,
                  byte[] output,
                  int outOffset)
           throws GeneralSecurityException

Perform a multiple-part encryption or decryption operation (depending on how this cipher was initialized), processing another data part.

Parameters:

input - the input buffer

inputOffset - the offset in input where the input starts

len - the input length

output - the buffer for the result

outOffset - the offset in output where the result is stored

Throws:

GeneralSecurityException - in case any error during encryption or decryption

getOutputSize

int getOutputSize(int len)

Returns the length in bytes that an output buffer would need to be in order to hold the result of the next doFinal operation, given the input length (in bytes).

Parameters:

len - input length (in bytes)

Returns:

output length in bytes

doFinal

void doFinal(byte[] plainText,
             int i)
      throws GeneralSecurityException

Finishes a multiple-part encryption or decryption operation, depending on how this cipher was initialized. Input data that may have been buffered during a previous update operation is processed, also the authentication tag is appended in the case of encryption, or verified in the case of decryption.

Parameters:

plainText - the buffer for the result

i - the offset in output where the result is stored

Throws:

GeneralSecurityException - in case any error during encryption or decryption