
Public key accelerator (PKA)
RM0453
716/1454
RM0453 Rev 2
24.5.2 Computation
times
The following tables summarize the PKA computation times, expressed in clock cycles.
Table 168. Modular exponentiation computation times
Exponent length
(in bits)
Mode
Modulus length (in bits)
1024
2048
3072
3
Normal
304000
814000
1728000
Fast
46000
164000
356000
17
Normal
326000
896000
1910000
Fast
68000
246000
534000
2
16
+ 1
Normal
416000
1222000
2616000
Fast
158000
572000
1244000
1024
Normal
11664000
-
-
Fast
11280000
-
-
CRT
(1)
1. CRT stands for chinese remainder theorem optimization (MODE bitfield = 0x07).
3546000
-
-
2048
Normal
-
83834000
-
Fast
-
82046000
-
CRT
-
23468000
-
3072
Normal
-
-
274954000
Fast
-
-
273522000
CRT
-
-
73378000
Table 169. ECC scalar multiplication computation times
(1)
1. These times depend on the number of “1”s included in the scalar parameter.
Mode
Modulus length (in bits)
160
192
256
320
384
512
521
Normal
1634000
2500000
4924000
8508000
13642000
28890000
33160000
Fast
1630000
2494000
4916000
8494000
13614000
28842000
33158000
Table 170. ECDSA signature average computation times
(1)
(2)
1. These values are average execution times of random moduli of given length, as they depend upon the
length and the value of the modulus.
2. The execution time for the moduli that define the finite field of NIST elliptic curves is shorter than that
needed for the moduli used for Brainpool elliptic curves or for random moduli of the same size.
Modulus length (in bits)
160
192
256
320
384
512
521
1760000
2664000
5249000
9016000
14596000
30618000
35540000