Datasheet

The following table details the size of the point and the precomputation table, depending on the chosen
window size option.
Table 43-91. ZpEcDsaQuickVerify Service Window Size and Precomputation Table Size Options
Option Specified Point and Precomputation
Table Size
PUKCL_ZPECCMUL_WINSIZE_A_VAL_TO_OPT(WA) WA in [2, 15] (3*(u2ModLength + 4)) * (2
(WA-2)
)
PUKCL_ZPECCMUL_WINSIZE_B_VAL_TO_OPT(WB) WB in [2,
15]
(3*(u2ModLength + 4)) * (2
(WB-2)
)
The Point Signature can be located in PUKCC RAM or in system RAM. If the Point Signature is entirely in
system RAM with no part in PUKCC RAM this can be signaled by us ing the option
PUKCL_ZPECCMUL_SCAL_IN_CLASSIC_RAM. In all other cases this option must not be used.
The following table describes this option.
Table 43-92. ZpEcDsaQuickVerify Service Point Signature in Classical RAM Option
Option Purpose
PUKCL_ZPECCMUL_SCAL_IN_CLASSIC_RAM The Point Signature can be located in Crypto RAM or
in system RAM. If the Point Signature is entirely in
system RAM with no part in PUKCC RAM this can be
signaled by using this option. In all other cases this
option must not be used.
43.3.6.13.6 Code Example
PUKCL_PARAM PUKCLParam;
PPUKCL_PARAM pvPUKCLParam = &PUKCLParam;
PUKCL(u2Option) = <Point Signature location and windows sizes>;
PUKCL_ZpEcDsaQuickVerify(pu1ModCnsBase) = <Base of the ram location of P and Cns>;
PUKCL_ZpEcDsaQuickVerify(u2ModLength) = <Byte length of P>;
PUKCL_ZpEcDsaQuickVerify(pu1PointABase) = <Base of the ram location of the A point>;
PUKCL_ZpEcDsaQuickVerify(pu1PointPublicKeyGen) = <Base of the Public Key>;
PUKCL_ZpEcDsaQuickVerify(pu1PointSignature) = <Base of the Signature (r, s)>;
PUKCL_ZpEcDsaQuickVerify(pu1OrderPointBase) = <Base of the order of the A point>;
PUKCL_ZpEcDsaQuickVerify(pu1AWorkBase) = <Base of the ram location of the parameter A of the
elliptic curve and workspace>;
PUKCL_ZpEcDsaQuickVerify(pu1HashBase) = <Base of the SHA resulting hash>;
PUKCL_ZpEcDsaQuickVerify(u2ScalarLength) = <Byte length of R and S in Point Signature>;
. . .
// vPUKCL_Process() is a macro command, which populates the service name
// and then calls the library...
vPUKCL_Process(ZpEcDsaQuickVerify, pvPUKCLParam);
if (PUKCL(u2Status) == PUKCL_OK)
{
...
}
else
if ( PUKCL(u2Status) = PUKCL_WRONG_SIGNATURE )
{
...
}
else // Manage the error
43.3.6.13.7 Constraints
No overlapping between either input and output are allowed. The following conditions must be avoided to
ensure that the service works correctly:
SAM D5x/E5x Family Data Sheet
Public Key Cryptography Controller (PUKCC)
© 2019 Microchip Technology Inc.
Datasheet
DS60001507E-page 1541