com.iotize.jvm

Class MbedTLS

java.lang.Object

com.iotize.jvm.MbedTLS

public final class MbedTLS
extends java.lang.Object

This class relays the calls to the MBED-TLS C functions, and other data computation helpers.

Field Summary

Fields

Modifier and Type	Field and Description
static int	AESCBC
static int	AESCFB128
static int	AESCFB8
static int	AESECB
static int	MBEDTLS_AES_DECRYPT
static int	MBEDTLS_AES_ENCRYPT

Constructor Summary

Constructors

Constructor and Description
MbedTLS(int algo, int mode) Creates a new MbedTLS, with the given AES algorithm and AES Mode.

Method Summary

Modifier and Type	Method and Description
int	aesCrypt(int length, java.lang.Integer ivOff, byte[] iv, byte[] input, byte[] output) Buffer Encryption/Decryption (depending on modeMBED)
int	aesSetkey(byte[] key, int keylen) Sets initial key before Encryption/Decryption
static short	CRC16(short polynom, short preloadValue, int length, byte[] buffer) Allows to compute 16 bits CRC on a given byte buffer (always starts from the first byte of the buffer)

Methods inherited from class java.lang.Object

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

Field Detail

MBEDTLS_AES_DECRYPT

public static final int MBEDTLS_AES_DECRYPT

See Also:

Constant Field Values

MBEDTLS_AES_ENCRYPT

public static final int MBEDTLS_AES_ENCRYPT

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Constant Field Values

AESECB

public static final int AESECB

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Constant Field Values

AESCBC

public static final int AESCBC

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Constant Field Values

AESCFB128

public static final int AESCFB128

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Constant Field Values

AESCFB8

public static final int AESCFB8

See Also:

Constant Field Values

Constructor Detail

MbedTLS

public MbedTLS(int algo,
               int mode)

Creates a new MbedTLS, with the given AES algorithm and AES Mode.

Parameters:

algo - AES algorithm to use for encryption

• AESECB = 0
• AESCBC = 1
• AESCFB128 = 2
• AESCFB8 = 3

mode - AES mode

• MBEDTLS_AES_DECRYPT = 0
• MBEDTLS_AES_ENCRYPT = 1

Method Detail

aesSetkey

public int aesSetkey(byte[] key,
                     int keylen)

Sets initial key before Encryption/Decryption

Parameters:

key - decryption key

keybits - must be 128, 192 or 256

Returns:

0 if successful

aesCrypt

public int aesCrypt(int length,
                    java.lang.Integer ivOff,
                    byte[] iv,
                    byte[] input,
                    byte[] output)

Buffer Encryption/Decryption (depending on modeMBED)

Parameters:

length - length of the input data

ivOff - offset in IV (updated after use) (only for AESCFB128)

iv - initialization vector (updated after use)

input - buffer holding the input data

output - buffer holding the output data

Returns:

0 if successful

CRC16

public static short CRC16(short polynom,
                          short preloadValue,
                          int length,
                          byte[] buffer)

Allows to compute 16 bits CRC on a given byte buffer (always starts from the first byte of the buffer)

Parameters:

polynom - the polynom used in the

preloadValue - the starting value of the calculation. Usually 0xFFFF

length - the number of bytes of the buffer used for the computation.

buffer - array of the bytes used for computation

Returns:

the 16bits value of the computed CRC