Cryptography for Intel® Integrated Performance Primitives Developer Reference

Developer Reference

Contents

GFpxInit

Initializes the context of a GF(p
d
) field.

Syntax

IppStatus ippsGFpxInit(const IppsGFpState* 
pParentGF
, int 
extDeg
, const IppsGfpElement* const
ppGroundElm[]
, int
polyTerms
, const IppsGFpMethod* 
method
, IppsGFpState* 
pGFpx
);
Include Files
ippcp.h
Parameters
pParentGF
Pointer to the context of the finite field GF(
p
) being extended.
extDeg
Degree of the extension.
ppGroundElm[]
Double pointer to the array of
IppsGFpElement
 contexts representing coefficients of the field polynomial.
polyTerms
Number of the field polynomial coefficients.
method
Pointer to the implementation of a basic arithmetic (methods) over the extended GF(
p
) finite field.
pGFpx
Pointer to the context of the GF(
p
d
) field being initialized.
Description
The function initializes the memory buffer
pGFpx
 associated with the
IppsGFpState
 context and sets up the specific irreducible polynomial. The initialized context is used in the functions that create contexts of elements of the GF(
p
d
) field and perform operations with the field elements.
The function assumes the use of a general field polynomial
g
(
x
) =
x
d
 +
x
d
 - 1
a
d
- 1
 +
x
d
 - 2
a
d
- 2
 + ⋯ +
x
1
a
1
 +
a
0
 over GF(
p
).
  • The function does not check the polynomial's irreducibility.
  • In general, the GF(
    p
    d
    ) extension requires a field polynomial
    g
    (
    x
    ) of degree
    d
    . However, because
    g
    (
    x
    ) is considered a monic polynomial (the coefficient of
    x
    d
     is always assumed equal to 1), the leading coefficient is not required:
    polyTerms
     <= (
    extDeg
     - 1).
  • When calling the functions over the GF(
    p
    d
    ) field, a properly initialized
    pParentGF
     context of the finite field GF(
    p
    ) is required.
  • Do not release the
    pParentGF
     context of the parent field as long as application deals with either the parent or the extended finite field pointed to by
    pGFpx
    .
Return Values
ippStsNoErr
Indicates no error. Any other value indicates an error or warning.
ippStsNullPtrErr
Indicates an error condition if any of the specified pointers is
NULL
.
ippStsContextMatchErr
Indicates an error condition if any of the context parameters referenced by elements of
ppGroundElm[]
 or
pParentGF
 does not match the operation.
ippStsBadArgErr
Indicates an error condition in the following cases:
  • extDeg
     > 8 or
    extDeg
     < 2.
  • polyTerms
     > (
    extDeg
     - 1) or
    polyTerms
     < 1.
  • method
     is not an output of a
    GFpxMethod
     function.
  • method
     is not compatible with the value of
    extDeg
    .
ippStsOutOfRangeErr
Indicates an error condition if the length of any of the values defined by
ppGroundElm[]
 is not equal to the length of an element of the parent finite field
pParentGF
.

Product and Performance Information

1

Performance varies by use, configuration and other factors. Learn more at www.Intel.com/PerformanceIndex.