129 lines
3.3 KiB
C
129 lines
3.3 KiB
C
/*
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* Elliptic Curve Digital Signature Algorithm (ECDSA)
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*
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*
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* This program generates one set of public and private keys in files
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* public.ecs and private.ecs respectively. Notice that the public key
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* can be much shorter in this scheme, for the same security level.
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*
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* It is assumed that Curve parameters are to be found in file common.ecs
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*
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* The curve is y^2=x^3+Ax+b mod p
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*
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* The file common.ecs is presumed to exist, and to contain the domain
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* information {p,A,B,q,x,y}, where A and B are curve parameters, (x,y) are
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* a point of order q, p is the prime modulus, and q is the order of the
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* point (x,y). In fact normally q is the prime number of points counted
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* on the curve.
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*
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* This program is written for static mode.
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* For a 160-bit modulus p, MR_STATIC could be defined as 5 in mirdef.h
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* for a 32-bit processor, or 10 for a 16-bit processor.
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* The system parameters can be found in the file common.ecs
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* Assumes MR_GENERIC_MT is defined in mirdef.h
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*
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*/
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#include <stdio.h>
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#include "miracl.h"
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int main()
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{
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FILE *fp;
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int ep,bits;
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epoint *g,*w;
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big a,b,p,q,x,y,d;
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long seed;
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miracl instance;
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miracl *mip=&instance;
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char mem[MR_BIG_RESERVE(7)]; /* reserve space on the stack for 7 bigs */
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char mem1[MR_ECP_RESERVE(2)]; /* and two elliptic curve points */
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memset(mem,0,MR_BIG_RESERVE(7));
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memset(mem1,0,MR_ECP_RESERVE(2));
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#ifndef MR_EDWARDS
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fp=fopen("common.ecs","rt");
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if (fp==NULL)
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{
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printf("file common.ecs does not exist\n");
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return 0;
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}
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fscanf(fp,"%d\n",&bits);
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#else
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fp=fopen("edwards.ecs","rt");
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if (fp==NULL)
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{
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printf("file edwards.ecs does not exist\n");
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return 0;
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}
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fscanf(fp,"%d\n",&bits);
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#endif
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mirsys(mip,bits/4,16); /* Use Hex internally */
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a=mirvar_mem(mip,mem,0);
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b=mirvar_mem(mip,mem,1);
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p=mirvar_mem(mip,mem,2);
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q=mirvar_mem(mip,mem,3);
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x=mirvar_mem(mip,mem,4);
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y=mirvar_mem(mip,mem,5);
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d=mirvar_mem(mip,mem,6);
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innum(mip,p,fp);
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innum(mip,a,fp);
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innum(mip,b,fp);
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innum(mip,q,fp);
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innum(mip,x,fp);
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innum(mip,y,fp);
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fclose(fp);
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/* randomise */
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printf("Enter 9 digit random number seed = ");
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scanf("%ld",&seed);
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getchar();
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irand(mip,seed);
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ecurve_init(mip,a,b,p,MR_PROJECTIVE); /* initialise curve */
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g=epoint_init_mem(mip,mem1,0);
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w=epoint_init_mem(mip,mem1,1);
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if (!epoint_set(mip,x,y,0,g)) /* initialise point of order q */
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{
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printf("Problem - point (x,y) is not on the curve\n");
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exit(0);
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}
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ecurve_mult(mip,q,g,w);
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if (!point_at_infinity(w))
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{
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printf("Problem - point (x,y) is not of order q\n");
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exit(0);
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}
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/* generate public/private keys */
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bigrand(mip,q,d);
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ecurve_mult(mip,d,g,g);
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ep=epoint_get(mip,g,x,x); /* compress point */
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printf("public key = %d ",ep);
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otnum(mip,x,stdout);
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fp=fopen("public.ecs","wt");
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fprintf(fp,"%d ",ep);
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otnum(mip,x,fp);
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fclose(fp);
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fp=fopen("private.ecs","wt");
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otnum(mip,d,fp);
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fclose(fp);
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/* clear all memory used */
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memset(mem,0,MR_BIG_RESERVE(7));
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memset(mem1,0,MR_ECP_RESERVE(2));
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return 0;
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}
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