Datasheet

}
else
if(PUKCL(u2Status) == PUKCL_WRONG_SIGNATURE)
{
...
}
else // Manage the error
43.3.7.10.6 Constraints
No overlapping between either input and output are allowed. The following conditions must be avoided to
ensure the service works correctly:
• nu1ModBase, nu1CnsBase, nu1PointABase, nu1PointPublicKeyGen, nu1PointSignature,
nu1OrderPointBase,nu1ABBase, nu1Workspace or nu1HashBase are not aligned on 32-bit
boundaries
• {nu1ModBase, u2ModLength + 4}, {nu1CnsBase, u2ModLength + 8}, {nu1PointABase,
3*u2ModLength + 12}, {nu1PointPublicKeyGen, 3*u2ModLength + 12}, {nu1PointSignature,
2*u2ScalarLength + 8}, {nu1OrderPointBase, u2ScalarLength + 4}, {nu1ABBase, 2*u2ModLength
+ 8}, {nu1Workspace, <WorkspaceLength>} or {nu1HashBase, u2ScalarLength + 4} are not in Crypto
RAM
• u2ModLength is either: < 12, > 0xffc or not a 32-bit length
• All overlapping between {nu1ModBase, u2ModLength + 4}, {nu1CnsBase, u2ModLength +8},
{nu1PointABase, 3*u2ModLength + 12}, {nu1PointPublicKeyGen, 3*u2ModLength + 12},
{nu1PointSignature, 2*u2ScalarLength + 8}, {nu1OrderPointBase, u2ScalarLength + 4},
{nu1ABBase, 2*u2ModLength + 8}, {nu1Workspace, <WorkspaceLength>} and {nu1HashBase,
u2ScalarLength + 4}
43.3.7.10.7 Status Returned Values
Table 43-111. GF2NEcDsaVerifyFast Service Return Codes
Returned Status Importance Meaning
PUKCL_OK – The computation passed without errors. The signature is
correct.
PUKCL_WRONG_SIGNATURE Warning The signature is incorrect.
43.3.8 PUKCL Requirements and Performance
43.3.8.1 Services Stack Usage
This library is using the main core to execute its computations, and therefore is also sharing some
resources with the application.
It may be important for the application to know RAM usage by the library functions and to be aware that
the library does not use any global variables.
The following table provides the minimum number of bytes used by the library that have to be available
on the stacks to ensure that the functionality can be executed correctly. In some cases, the library may
use less bytes than the specified number for some options. This table contains estimated values.
Table 43-112. Services Stack Usage
PUKCL Service STACK Usage (Bytes)
SelfTest 112
ClearFlags 0
SAM D5x/E5x Family Data Sheet
Public Key Cryptography Controller (PUKCC)
© 2019 Microchip Technology Inc.
Datasheet
DS60001507E-page 1566