This is an automated email from the ASF dual-hosted git repository. sandreoli pushed a commit to branch add-multiple-exponent-api in repository https://gitbox.apache.org/repos/asf/incubator-milagro-crypto-c.git
commit 32ac3e7fbf23be73b7965c47e043250477d09cf0 Author: Samuele Andreoli <[email protected]> AuthorDate: Tue Feb 4 10:18:34 2020 +0000 add constant time triple exponent --- include/ff.h.in | 16 ++++++++++- src/ff.c.in | 58 +++++++++++++++++++++++++++++++++++++++ test/test_ff_consistency_WWW.c.in | 10 +++++++ 3 files changed, 83 insertions(+), 1 deletion(-) diff --git a/include/ff.h.in b/include/ff.h.in index 7096162..0bcf458 100644 --- a/include/ff.h.in +++ b/include/ff.h.in @@ -253,7 +253,7 @@ extern void FF_WWW_skpow(BIG_XXX *r,BIG_XXX *x,BIG_XXX * e,BIG_XXX *p,int n, int @param n size of FF in BIGs */ extern void FF_WWW_skspow(BIG_XXX *r,BIG_XXX *x,BIG_XXX e,BIG_XXX *p,int n); -/** @brief Calculate r=x^e.y^f mod p for big e and f, side channel resistant +/** @brief Calculate r=x^e.y^f mod p for FF e and f, side channel resistant * @param r FF instance, on exit = x^e.y^f mod p @param x FF instance @@ -265,6 +265,20 @@ extern void FF_WWW_skspow(BIG_XXX *r,BIG_XXX *x,BIG_XXX e,BIG_XXX *p,int n); @param en size of the exponent in BIGs */ extern void FF_WWW_skpow2(BIG_XXX *r,BIG_XXX *x, BIG_XXX *e, BIG_XXX *y, BIG_XXX *f, BIG_XXX *p, int n, int en); +/** @brief Calculate r=x^e.y^f.z^g mod p for FF e, f and g, side channel resistant + * + @param r FF instance, on exit = x^e.y^f.z^g mod p + @param x FF instance + @param e FF exponent + @param y FF instance + @param f FF exponent + @param z FF instance + @param g FF exponent + @param p FF modulus + @param n size of FF in BIGs + @param en size of the exponent in BIGs + */ +extern void FF_WWW_skpow3(BIG_XXX *r,BIG_XXX *x, BIG_XXX *e, BIG_XXX *y, BIG_XXX *f, BIG_XXX *z, BIG_XXX *g, BIG_XXX *p, int n, int en); /** @brief Calculate r=x^e mod p * For very short integer exponent diff --git a/src/ff.c.in b/src/ff.c.in index 2ce8da1..3f83bc2 100644 --- a/src/ff.c.in +++ b/src/ff.c.in @@ -866,6 +866,64 @@ void FF_WWW_skpow2(BIG_XXX r[],BIG_XXX x[], BIG_XXX e[], BIG_XXX y[], BIG_XXX f[ FF_WWW_redc(r,p,ND,n); } +/* r=x^e*y^f mod p - side channel resistant */ +void FF_WWW_skpow3(BIG_XXX r[],BIG_XXX x[], BIG_XXX e[], BIG_XXX y[], BIG_XXX f[], BIG_XXX z[], BIG_XXX g[], BIG_XXX p[], int n, int en) +{ + int i,b; +#ifndef C99 + BIG_XXX xn[FFLEN_WWW],yn[FFLEN_WWW],zn[FFLEN_WWW],xy[FFLEN_WWW],xz[FFLEN_WWW],yz[FFLEN_WWW],xyz[FFLEN_WWW],w[FFLEN_WWW],ND[FFLEN_WWW]; +#else + BIG_XXX xn[n],yn[n],zn[n],xy[n],xz[n],yz[n],xyz[n],w[n],ND[n]; +#endif + + FF_WWW_invmod2m(ND, p, n); + + FF_WWW_copy(xn, x, n); + FF_WWW_copy(yn, y, n); + FF_WWW_copy(zn, z, n); + FF_WWW_nres(xn, p, n); + FF_WWW_nres(yn, p, n); + FF_WWW_nres(zn, p, n); + FF_WWW_modmul(xy, xn, yn, p, ND, n); + FF_WWW_modmul(xz, xn, zn, p, ND, n); + FF_WWW_modmul(yz, yn, zn, p, ND, n); + FF_WWW_modmul(xyz, xy, zn, p, ND, n); + FF_WWW_one(w, n); + FF_WWW_one(r, n); + FF_WWW_nres(w, p, n); + FF_WWW_nres(r, p, n); + + for (i=8*MODBYTES_XXX*en-1; i>=0; i--) + { + b = BIG_XXX_bit(g[i/BIGBITS_XXX],i%BIGBITS_XXX); + b <<= 1; + b = b | BIG_XXX_bit(f[i/BIGBITS_XXX],i%BIGBITS_XXX); + b <<= 1; + b = b | BIG_XXX_bit(e[i/BIGBITS_XXX],i%BIGBITS_XXX); + + FF_WWW_cswap(w, xn, b == 0x01, n); + FF_WWW_cswap(w, yn, b == 0x02, n); + FF_WWW_cswap(w, zn, b == 0x04, n); + FF_WWW_cswap(w, xy, b == 0x03, n); + FF_WWW_cswap(w, xz, b == 0x05, n); + FF_WWW_cswap(w, yz, b == 0x06, n); + FF_WWW_cswap(w, xyz, b == 0x07, n); + + FF_WWW_modsqr(r, r, p, ND, n); + FF_WWW_modmul(r, w, r, p, ND, n); + + FF_WWW_cswap(w, xn, b == 0x01, n); + FF_WWW_cswap(w, yn, b == 0x02, n); + FF_WWW_cswap(w, zn, b == 0x04, n); + FF_WWW_cswap(w, xy, b == 0x03, n); + FF_WWW_cswap(w, xz, b == 0x05, n); + FF_WWW_cswap(w, yz, b == 0x06, n); + FF_WWW_cswap(w, xyz, b == 0x07, n); + } + + FF_WWW_redc(r, p, ND, n); +} + /* raise to an integer power - right-to-left method */ void FF_WWW_power(BIG_XXX r[],BIG_XXX x[],int e,BIG_XXX p[],int n) { diff --git a/test/test_ff_consistency_WWW.c.in b/test/test_ff_consistency_WWW.c.in index 56fa552..f077a5d 100644 --- a/test/test_ff_consistency_WWW.c.in +++ b/test/test_ff_consistency_WWW.c.in @@ -324,6 +324,16 @@ int main() exit(EXIT_FAILURE); } + // Test triple exponent for secret key + FF_WWW_zero(N, HFLEN_WWW); + FF_WWW_skpow3(N, A, E, B, F, C, G, P, HFLEN_WWW, HFLEN_WWW); + + if(FF_WWW_comp(N, L, HFLEN_WWW)) + { + printf("ERROR testing pow3"); + exit(EXIT_FAILURE); + } + // Test quadruple exponent FF_WWW_pow(N, D, H, P, HFLEN_WWW); FF_WWW_mul(Q, L, N, HFLEN_WWW);
