mirror of
https://github.com/zerotier/ZeroTierOne.git
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61 lines
1.9 KiB
C
61 lines
1.9 KiB
C
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#include "fe25519.h"
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void fe25519_invert(fe25519 *r, const fe25519 *x)
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{
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fe25519 z2;
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fe25519 z9;
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fe25519 z11;
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fe25519 z2_5_0;
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fe25519 z2_10_0;
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fe25519 z2_20_0;
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fe25519 z2_50_0;
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fe25519 z2_100_0;
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fe25519 t;
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int i;
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/* 2 */ fe25519_square(&z2,x);
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/* 4 */ fe25519_square(&t,&z2);
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/* 8 */ fe25519_square(&t,&t);
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/* 9 */ fe25519_mul(&z9,&t,x);
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/* 11 */ fe25519_mul(&z11,&z9,&z2);
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/* 22 */ fe25519_square(&t,&z11);
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/* 2^5 - 2^0 = 31 */ fe25519_mul(&z2_5_0,&t,&z9);
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/* 2^6 - 2^1 */ fe25519_square(&t,&z2_5_0);
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/* 2^20 - 2^10 */ for (i = 1;i < 5;i++) { fe25519_square(&t,&t); }
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/* 2^10 - 2^0 */ fe25519_mul(&z2_10_0,&t,&z2_5_0);
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/* 2^11 - 2^1 */ fe25519_square(&t,&z2_10_0);
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/* 2^20 - 2^10 */ for (i = 1;i < 10;i++) { fe25519_square(&t,&t); }
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/* 2^20 - 2^0 */ fe25519_mul(&z2_20_0,&t,&z2_10_0);
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/* 2^21 - 2^1 */ fe25519_square(&t,&z2_20_0);
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/* 2^40 - 2^20 */ for (i = 1;i < 20;i++) { fe25519_square(&t,&t); }
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/* 2^40 - 2^0 */ fe25519_mul(&t,&t,&z2_20_0);
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/* 2^41 - 2^1 */ fe25519_square(&t,&t);
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/* 2^50 - 2^10 */ for (i = 1;i < 10;i++) { fe25519_square(&t,&t); }
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/* 2^50 - 2^0 */ fe25519_mul(&z2_50_0,&t,&z2_10_0);
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/* 2^51 - 2^1 */ fe25519_square(&t,&z2_50_0);
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/* 2^100 - 2^50 */ for (i = 1;i < 50;i++) { fe25519_square(&t,&t); }
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/* 2^100 - 2^0 */ fe25519_mul(&z2_100_0,&t,&z2_50_0);
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/* 2^101 - 2^1 */ fe25519_square(&t,&z2_100_0);
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/* 2^200 - 2^100 */ for (i = 1;i < 100;i++) { fe25519_square(&t,&t); }
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/* 2^200 - 2^0 */ fe25519_mul(&t,&t,&z2_100_0);
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/* 2^201 - 2^1 */ fe25519_square(&t,&t);
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/* 2^250 - 2^50 */ for (i = 1;i < 50;i++) { fe25519_square(&t,&t); }
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/* 2^250 - 2^0 */ fe25519_mul(&t,&t,&z2_50_0);
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/* 2^251 - 2^1 */ fe25519_square(&t,&t);
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/* 2^252 - 2^2 */ fe25519_square(&t,&t);
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/* 2^253 - 2^3 */ fe25519_square(&t,&t);
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/* 2^254 - 2^4 */ fe25519_square(&t,&t);
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/* 2^255 - 2^5 */ fe25519_square(&t,&t);
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/* 2^255 - 21 */ fe25519_mul(r,&t,&z11);
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}
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