Datasheet

Important: Before using this service:
• Ensure that the constant Cns has been calculated with the setup of the Modular Reduction
service.
• Be sure to follow the directives given for the RNG on the chip you use (particularly
initialization, seeding) and compulsorily start the RNG
.
43.3.6.9.4 Parameters Definition
Table 43-81. ZpEccRandomiseCoordinate Service Parameters
Parameter Type Direction Location Data Length Before
Executing the
Service
After
Executing the
Service
nu1ModBase nu1 I Crypto RAM u2ModLength + 4 Base of
modulus P
Base of
modulus P
nu1CnsBase nu1 I Crypto RAM u2ModLength + 8 Base of Cns Base of Cns
u2ModLength u2 I – – Length of
modulus P
Length of
modulus P
nu1PointBase nu1 I Crypto RAM 3*u2ModLength
+ 12
Input point Resulting point
nu1RandomBase nu1 I Crypto RAM u2ModLength + 4 Random Corrupted
nu1Workspace nu1 I Crypto RAM 3*u2ModLength
+ 28
– Workspace
43.3.6.9.5 Code Example
PUKCL_PARAM PUKCLParam;
PPUKCL_PARAM pvPUKCLParam = &PUKCLParam;
// ! The Random Number Generator must be initialized and started
// ! following the directives given for the RNG on the chip
PUKCL (u2Option) = 0;
// Depending on the option specified, not all fields should be filled
PUKCL _ZpEccRandomiseCoordinate(nu1ModBase) = <Base of the ram location of P>;
PUKCL _ZpEccRandomiseCoordinate(u2ModLength) = <Byte length of P>;
PUKCL _ZpEccRandomiseCoordinate(nu1CnsBase) = <Base of the ram location of Cns>;
PUKCL_ZpEccRandomiseCoordinate(nu1RandomBase) = <Base of the ram location where the the RNG
is stored>;
PUKCL _ZpEccRandomiseCoordinate(nu1PointBase) = <Base of the ram location of the point>;
PUKCL _ZpEccRandomiseCoordinate(nu1Workspace) = <Base of the ram location of the workspace>;
...
// vPUKCL_Process() is a macro command, which populates the service name
// and then calls the library...
vPUKCL_Process(ZpEccRandomiseCoordinate,&PUKCLParam);
if (PUKCL (u2Status) == PUKCL_OK)
{
...
}
else // Manage the error
SAM D5x/E5x Family Data Sheet
Public Key Cryptography Controller (PUKCC)
© 2019 Microchip Technology Inc.
Datasheet
DS60001507E-page 1528