CC2520_11 Datasheet, PDF (94/133 Pages) Texas Instruments – 2.4 GHZ IEEE 802.15.4/ZIGBEE RF TRANSCEIVER

CC2520 DATASHEET
2.4 GHZ IEEE 802.15.4/ZIGBEE® RF TRANSCEIVER
SWRS068 – DECEMBER 2007
Memory before
A+2^C-1
2^C bytes
A
INC(P,C,A)
Increment
A+15-C
16-C bytes plaintext
A
16K+15
16 bytes key
16K
A+15-C
16-C bytes plaintext
A
16K+15
16 bytes key
16K
ECB(P,K,C,A,E)
zero
padding to
16 bytes
AES
encryption
ECBO(P,K,C,A)
zero
padding to
16 bytes
AES
encryption
Memory after
A+2^C-1
A
2^C bytes
0≤C≤2
E+15
16 bytes ciphertext
E
A+15-C
16-C bytes plaintext
A
16K+15
16 bytes key
16K
A+15
16 bytes ciphertext
A
16K+15
16 bytes key
16K
E+15-C
16-C bytes plaintext
E
A+15
16 bytes counter
A
16K+15
16 bytes key
16K
ECBX(P,K,C,A,E)
AES
encryption
Figure 36: Simple encryption instructions
E+15-C
16-C bytes ciphertext
E
A+15
16 bytes counter
A
16K+15
16 bytes key
16K
26.2 INC
The INC instruction increments 1, 2 or 4 bytes, with the LSB at address A. Note that C=3 is an illegal
parameter value.
26.3 ECB
The ECB instruction performs basic block encryption. It is mainly intended as a function used by the more
complicated instructions such as CBC-MAC and CCM. ECB by itself is not very useful, because there is no
decryption instruction. The cipher text output can not be recovered. This should not be considered as a
weakness, because ECB block encryption/decryption is not considered to be a secure form of
communicating.
The values of the parameters E and C should be selected with care so that the instruction does not
overwrite a section of the memory that is already in use. The ECB instruction will work exactly as ECBO if
E=A.
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