CRS-AVR010X-ECC cryptographic software implements ECDSA digital signature
and ECDH algorithm. It supports 8-bit AVR microcontrollers manufactured
by Atmel. Since complex calculations are required, we strongly recommend to use the
software only for ATmega microcontrollers.
Moreover, the software offers the implementation of
CRS-AVR020X-RBG random bit generator based on the properties of Analog-to-Digital
Converter. Hence the functionality of the software is full only when used along with
microcontrollers with built-in converter.
Depending on the configuration, the CRS-AVR010X-ECC implementation requires from 5 to
8 kB of Flash memory of microcontroller and from 750 to 900 B of SRAM memory.
The software is available in four versions, each one offering different level of
cryptographic protection. The table below presents the relation between the implemented
domain of elliptic curve and the level of protection provided. Every row of the table
corresponds to an equal level of protection. For instance: the cryptographic power
of the secp160r1 domain is equal to the power of an 80-bit key symmetric cipher and the
power of a 1024-bit RSA key.
The cryptographic domains employed are commonly known and had been published in the
SEC 2 standard.
However, choosing the most suitable domain for a particular application is not an
easy task. First of all, one should decide whether to give priority to the speed or
to the security level. The secp160r1 domain is the fastest one but provides a lower
level of protection comparing with secp192r1, secp224r1 and secp256r1. The table
below presents predictions made by the National Institute for Standards and Technology
(NIST) regarding the time period until which
particular domains are expected to assure security.
The times of completing particular operations are available in the section entitled
The table below presents operating times for particular domains
The operation of the ECDSA signature may be accelerated by employing additional
memory. The table below presents the indispensable memory and operating time for
completing a signature for particular domains.
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