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#include <stdio.h>
#include <stdlib.h>

#include <openssl/sha.h>
#include <openssl/ecdsa.h>
#include <openssl/ripemd.h>
#include <openssl/ec.h>
#include <openssl/obj_mac.h>
#include <openssl/bn.h>


#include "hash.h"


unsigned char* privkey2addr(unsigned char* input)
{
   unsigned char* output;

   int ret;    /* return value of the sign-function */
   ECDSA_SIG *sig;   /* result of the signing process, containing both r and s */
   EC_KEY *eckey = EC_KEY_new();    /* create new key for the signing process */
   EC_GROUP *ecgroup = EC_GROUP_new_by_curve_name(NID_secp256k1);    /* set secp256k1 as the signing method */

   unsigned char *r, *s;

   if(eckey == NULL || ecgroup == NULL) {    /* check for errors */
      printf("Initializing of eckey or ecgroup failed!\n");
      return NULL;
   }

   if(EC_KEY_set_group(eckey,ecgroup) != 1) {   /* set signing method and check for errors */
      printf("Setting group for eckey failed!\n");
      return NULL;
   }

   if(EC_KEY_generate_key(eckey) != 1) {  /* generete key and check for errors */
      printf("Generating eckey failed!\n");
      return NULL;
   }

   sig = ECDSA_do_sign(input, 32, eckey); /* sign the input */

   if(sig==NULL) {   /* error? */
      printf("Signing of input failed!\n");
      return NULL;
   }

   ret = ECDSA_do_verify(input, 32, sig, eckey);   /* verify result */

   if(ret == -1 || ret == 0) {   /* error? */
      printf("Verifying failed!\n");
      return NULL;
   }

   r = malloc(32);   /* allocate 32 bit space for both r and s */
   s = malloc(32);

   if(BN_bn2bin(sig->r, r) != 32) { /* export BIGNUM to array of chars, check for invalid length */
      printf("Invalid result length!\n");
      return NULL;
   }

   if(BN_bn2bin(sig->s, s) != 32) { /* export BIGNUM to array of chars, check for invalid length */
      printf("Invalid result length!\n");
      return NULL;
   }

   int i;

   printf("X: "); /* print both r and s for debug reasons */
   for(i=0; i<32; i++) {
      printf("%02x", (unsigned char) *(r+i));
   }
   putc('\n', stdout);

   printf("Y: ");
   for(i=0; i<32; i++) {
      printf("%02x", (unsigned char) *(s+i));
   }
   putc('\n', stdout);


   unsigned char *pubkey_raw; /* raw public key '*/

   pubkey_raw = malloc(65); /* reserve 65 byte of space for the pubkey */

   *pubkey_raw = 0x04;   /* merge 0x04, r and s to the pubkey */

   for(i=0; i < 32; i++)
      *(pubkey_raw+i+1) = *(r+i);

   for(i = 0; i < 32; i++)
      *(pubkey_raw+i+33) = *(s+i);

   free(r); /* free no longer required memory */
   free(s);
   EC_KEY_free(eckey);
   EC_GROUP_free(ecgroup);
   ECDSA_SIG_free(sig);

   unsigned char *pubkey_stage1; /* public key after first stage */

   pubkey_stage1 = malloc(20);   /* reserve 20 bytes of memory */

   pubkey_stage1 = RIPEMD160(SHA256(pubkey_raw, 65, (unsigned char*) NULL), 32, (unsigned char *) NULL); /* hash it! */

   unsigned char *pubkey_stage2; /* public key after seconf stage */

   pubkey_stage2 = malloc(25);   /* reserve 25 bytes of memory */

   *pubkey_stage2 = 0x00;  /* put 0x00 at the beginning for main network */

   for(i = 0; i < 20; i++) /* add the result of stage one */
      *(pubkey_stage2+i+1) = *(pubkey_stage1+i);

   unsigned char *result;  /* the binary address */

   result = malloc(32); /* reserve 32 bytes of memory */

   result = SHA256(SHA256(pubkey_stage2, 32, (unsigned char*) NULL), 32, (unsigned char*) NULL);   /* calculate checksum */


   for(i = 0; i < 4; i++)  /* append checksum to binary address */
      *(pubkey_stage2+i+21) = *(result+i);

   printf("Binary address: ");   /* print binary address */
   for(i=0; i<25; i++) {
      printf("%02x", (unsigned char) *(pubkey_stage2+i));
   }
   putc('\n', stdout);



   output = malloc(35);

   output = base58(pubkey_stage2);

   return output;
}




unsigned char* base58(unsigned char* input)
{
   unsigned char *output;
   BIGNUM *a;
   BIGNUM *b58;
   BIGNUM *rem;

   int i;

   unsigned char *bc58;
   bc58 = malloc(1);
   *bc58=58;

   unsigned char *rest;
   rest = malloc(1);

   const char *alphabet = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz";

   BN_CTX *ctx = BN_CTX_new();
   BN_CTX_init(ctx);


   a = BN_new();
   BN_init(a);

   b58 = BN_new();
   BN_init(b58);

   rem = BN_new();
   BN_init(rem);

   BN_bin2bn((const unsigned char*) input, 25, a);

   BN_bin2bn((const unsigned char*) bc58 , 1, b58);

   output = malloc(35);

   i = 0;

   while(BN_is_zero(a) != 1) {
      BN_div(a, rem, a, b58, ctx);
      BN_bn2bin(rem, rest);
      *(output+i) = alphabet[*rest];
      i++;
   }

   int n = 0, b = 0;

   for(b = 0; b < 25; b++) {
      if(*(input+b)==0)
         n++;
      if(*(input+b)!=0)
         break;
   }

   printf("%i, %i\n", n, i);

   for(b = 0; b < n; b++) {
      *(output+i+b) = alphabet[0];
   }




   return output;
}

Private Key: 1809c5d482b97ec84dd7e94cc4cbed460fd878025b52b1011970a3626e64eda8
X: c2429880bd9be5ebe72f00cc34a878cc6e5060f749b7b37957a2f087817e36c0
Y: 4117f999affb005828fd957cfaccc60530c871a05b7d205746d2ca68082d2d7d
Binary address: 0075c5672c37a9140631a0bf915c0e6aa356a832b04bd05648
1, 33
Address: 5ZL8VhHCBiePTgdNn4uQYanWMMgHFYijB1
355a4c3856684843426965505467644e6e34755159616e574d4d67484659696a423100