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40
41 /*
42 // Intel(R) Integrated Performance Primitives. Cryptography Primitives.
43 // GF(p^d) methods
44 //
45 */
46 #include "owncp.h"
47
48 #include "pcpgfpxstuff.h"
49 #include "pcpgfpxmethod_com.h"
50
51 //tbcd: temporary excluded: #include <assert.h>
52
cpGFpxMul_com(BNU_CHUNK_T * pR,const BNU_CHUNK_T * pA,const BNU_CHUNK_T * pB,gsEngine * pGFEx)53 BNU_CHUNK_T* cpGFpxMul_com(BNU_CHUNK_T* pR, const BNU_CHUNK_T* pA, const BNU_CHUNK_T* pB, gsEngine* pGFEx)
54 {
55 int extDegree = GFP_EXTDEGREE(pGFEx);
56
57 BNU_CHUNK_T* pGFpolynomial = GFP_MODULUS(pGFEx);
58 int degR = extDegree-1;
59 int elemLen= GFP_FELEN(pGFEx);
60
61 int degB = degR;
62 BNU_CHUNK_T* pTmpProduct = cpGFpGetPool(2, pGFEx);
63 BNU_CHUNK_T* pTmpResult = pTmpProduct + GFP_PELEN(pGFEx);
64
65 gsEngine* pGroundGFE = GFP_PARENT(pGFEx);
66 BNU_CHUNK_T* r = cpGFpGetPool(1, pGroundGFE);
67 int groundElemLen = GFP_FELEN(pGroundGFE);
68
69 const BNU_CHUNK_T* pTmpB = GFPX_IDX_ELEMENT(pB, degB, groundElemLen);
70
71 //tbcd: temporary excluded: assert(NULL!=pTmpProduct && NULL!=r);
72
73 /* clear temporary */
74 cpGFpElementPadd(pTmpProduct, elemLen, 0);
75
76 /* R = A * B[degB-1] */
77 cpGFpxMul_GFE(pTmpResult, pA, pTmpB, pGFEx);
78
79 for(degB-=1; degB>=0; degB--) {
80 /* save R[degR-1] */
81 cpGFpElementCopy(r, GFPX_IDX_ELEMENT(pTmpResult, degR, groundElemLen), groundElemLen);
82
83 { /* R = R * x */
84 int j;
85 for (j=degR; j>=1; j--)
86 cpGFpElementCopy(GFPX_IDX_ELEMENT(pTmpResult, j, groundElemLen), GFPX_IDX_ELEMENT(pTmpResult, j-1, groundElemLen), groundElemLen);
87 cpGFpElementPadd(pTmpResult, groundElemLen, 0);
88 }
89
90 cpGFpxMul_GFE(pTmpProduct, pGFpolynomial, r, pGFEx);
91 GFP_METHOD(pGFEx)->sub(pTmpResult, pTmpResult, pTmpProduct, pGFEx);
92
93 /* B[degB-i] */
94 pTmpB -= groundElemLen;
95 cpGFpxMul_GFE(pTmpProduct, pA, pTmpB, pGFEx);
96 GFP_METHOD(pGFEx)->add(pTmpResult, pTmpResult, pTmpProduct, pGFEx);
97 }
98
99 /* copy result */
100 cpGFpElementCopy(pR, pTmpResult, elemLen);
101
102 /* release pools */
103 cpGFpReleasePool(1, pGroundGFE);
104 cpGFpReleasePool(2, pGFEx);
105
106 return pR;
107 }
108