Function

Decrypt bufferRF

Purpose

The decryption of payload data encrypted by encryptBufferRF

Syntax

void decryptBufferRF(uns8 X)

Parameters

X.0-5:   Number of 16 B blocks to be decrypted (1 to 4)

X.6:

•     0        User key specified by setUserKey is used

•     1        User key in bufferINFO[0 to 15] is used

Input values

 –

Return value

  –

Output values

The specified number of blocks in bufferRF is decrypted by the User key.

Preconditions

•   The same User key must be used as the one used for preceding encryption.

•   For networking as well as non-networking communication.

•   It is not necessary to decrypt data within IQRF wireless. Decryption can alternatively be done e.g. by a superordinate system.

Remarks

•     If blocks < 4, the rest of bufferRF remains unchanged.

•     Industry standard AES-128 b ECB decryption is used.

Side effects

  –

See also

setUserKey, encryptBufferRF

Example 1

bufferINFO[0 to 15] = ...;

setUserKey();                    // Must be the same key as for encryption

     ...

if (RFRXpacket())

{

  decryptBufferRF(2);            // 32 B decrypted, the rest remains unchanged

     ...                         // User key defined by setUserKey()

}

Example 2

bufferINFO[0 to 15] = ...;              // Must be the same key as for encryption

     ...

if (RFRXpacket())

{

  decryptBufferRF(0b01000000 | 2);      // 32 B decrypted, the rest remains unchanged

     ...                                // User key from bufferINFO

}