#include <openssl/bn.h>
#include <openssl/dsa.h>
#include <openssl/fips.h>
#include <openssl/err.h>
#include <string.h>

int hex2bin(const char *in, unsigned char *out)
    {
    int n1, n2;
    unsigned char ch;

    for (n1=0,n2=0 ; in[n1] ; )
	{ /* first byte */
	if ((in[n1] >= '0') && (in[n1] <= '9'))
	    ch = in[n1++] - '0';
	else if ((in[n1] >= 'A') && (in[n1] <= 'F'))
	    ch = in[n1++] - 'A' + 10;
	else if ((in[n1] >= 'a') && (in[n1] <= 'f'))
	    ch = in[n1++] - 'a' + 10;
	else
	    return -1;
	if(!in[n1])
	    {
	    out[n2++]=ch;
	    break;
	    }
	out[n2] = ch << 4;
	/* second byte */
	if ((in[n1] >= '0') && (in[n1] <= '9'))
	    ch = in[n1++] - '0';
	else if ((in[n1] >= 'A') && (in[n1] <= 'F'))
	    ch = in[n1++] - 'A' + 10;
	else if ((in[n1] >= 'a') && (in[n1] <= 'f'))
	    ch = in[n1++] - 'a' + 10;
	else
	    return -1;
	out[n2++] |= ch;
	}
    return n2;
    }

int bin2hex(const unsigned char *in,int len,char *out)
    {
    int n1, n2;
    unsigned char ch;

    for (n1=0,n2=0 ; n1 < len ; ++n1)
	{
	ch=in[n1] >> 4;
	if (ch <= 0x09)
	    out[n2++]=ch+'0';
	else
	    out[n2++]=ch-10+'a';
	ch=in[n1] & 0x0f;
	if(ch <= 0x09)
	    out[n2++]=ch+'0';
	else
	    out[n2++]=ch-10+'a';
	}
    out[n2]='\0';
    return n2;
    }

void pv(char *tag,const unsigned char *val,int len)
    {
    char obuf[2048];
    int olen;

    olen=bin2hex(val,len,obuf);
    printf("%s= %s\n", tag,obuf);
    }

void primes()
    {
    char buf[10240];

    while(fgets(buf,sizeof buf,stdin) != NULL)
	{
	fputs(buf,stdout);
	if(!strncmp(buf,"Prime= ",7))
	    {
	    BIGNUM *pp;

	    pp=BN_new();
	    BN_hex2bn(&pp,buf+7);
	    printf("result= %c\n",
		   BN_is_prime(pp,20,NULL,NULL,NULL) ? 'P' : 'F');
	    }	    
	}
    }

void pqg()
    {
    char buf[1024];
    int nmod=0;

    while(fgets(buf,sizeof buf,stdin) != NULL)
	{
	fputs(buf,stdout);
	if(!strncmp(buf,"[mod=",5))
	    nmod=atoi(buf+5);
	else if(!strncmp(buf,"N= ",3))
	    {
	    int n=atoi(buf+3);

	    while(n--)
		{
		unsigned char seed[20];
		DSA *dsa;
		int counter;
		unsigned long h;

		dsa=DSA_generate_parameters(nmod,seed,0,&counter,&h,NULL,NULL);
		printf("P= %s\n",BN_bn2hex(dsa->p));
		printf("Q= %s\n",BN_bn2hex(dsa->q));
		printf("G= %s\n",BN_bn2hex(dsa->g));
		pv("Seed",seed,20);
		printf("H= %lx\n",h);
		printf("C= %d\n",counter);
		}
	    }
	}
    }

int main(int argc,char **argv)
    {
    if(argc != 2)
	{
	fprintf(stderr,"%s [primes|pqg]\n",argv[0]);
	exit(1);
	}
    if(!FIPS_mode_set(1,argv[0]))
	{
	ERR_load_crypto_strings();
	ERR_print_errors(BIO_new_fp(stderr,BIO_NOCLOSE));
	exit(1);
	}
    if(!strcmp(argv[1],"primes"))
	primes();
    else
	pqg();

    return 0;
    }