c - Any possibility of using KeyBlob (stored in byte format) for crypto operations -

created key blob using openssl. need use keyblob crypto operations(like- encrypt, decrypt, signing , verifying) using openssl. code platform independent.

// assume "private_key" having private key // keyblob byte array of size 2048 // e,n,p,q,dmp1,dmq1,iqmp,d of type bignum* , initialized null      rsa* rsa = new rsa( );  rsa = evp_pkey_get1_rsa ( private_key ); if ( null == rsa ) {     hresult = errno;     printf("\n\terror:evp_pkey_get1_rsa failed\n\n");     break; } // if else {     //printf("\n\trsa private key generated successfully\n\n"); } // else  e = rsa->e; n = rsa->n; p = rsa->p; q = rsa->q; dmp1 = rsa->dmp1; dmq1 = rsa->dmq1; iqmp = rsa->iqmp; d = rsa->d; version = rsa->version;  // convert bignum binary. // modulus (n) modulus = (unsigned char*)calloc(rsa_size(rsa), sizeof(unsigned char)); iresult = bn_bn2bin(n, modulus); if( !iresult ) {    hresult = errno;    printf("\n\terror:bn_bn2bin failed\n\n");    break; } // if  // exponent1 (dmp1) exponent1 = (unsigned char*)calloc(rsa_size(rsa), sizeof(unsigned char)); iresult = bn_bn2bin(dmp1, exponent1); if( !iresult ) {    hresult = errno;    printf("\n\terror:bn_bn2bin failed\n\n");    break; } // if  // exponent2 (dmq1) exponent2 = (unsigned char*)calloc(rsa_size(rsa), sizeof(unsigned char)); iresult = bn_bn2bin(dmq1, exponent2); if( !iresult ) {    hresult = errno;    printf("\n\terror:bn_bn2bin failed\n\n");    break; } // if  // prime1 (p) prime1 = (unsigned char*)calloc(rsa_size(rsa), sizeof(unsigned char)); iresult = bn_bn2bin(p, prime1); if( !iresult ) {    hresult = errno;    printf("\n\terror:bn_bn2bin failed\n\n");    break; } // if  // prime2 (q) prime2 = (unsigned char*)calloc(rsa_size(rsa), sizeof(unsigned char)); iresult = bn_bn2bin(q, prime2); if( !iresult ) {    hresult = errno;    printf("\n\terror:bn_bn2bin failed\n\n");    break; } // if  // public exponent (e) public_exponent = (unsigned char*)calloc(rsa_size(rsa), sizeof(unsigned char)); iresult = bn_bn2bin(e, public_exponent); if( !iresult ) {    hresult = errno;    printf("\n\terror:bn_bn2bin failed\n\n");    break; } // if  // private exponent (d) private_exponent = (unsigned char*)calloc(rsa_size(rsa), sizeof(unsigned char)); iresult = bn_bn2bin(d, private_exponent); if( !iresult ) {    hresult = errno;    printf("\n\terror:bn_bn2bin failed\n\n");    break; } // if  // coefficient (iqmp) coefficient = (unsigned char*)calloc(rsa_size(rsa), sizeof(unsigned char));  iresult = bn_bn2bin(iqmp, coefficient); if( !iresult ) {    hresult = errno;    printf("\n\terror:bn_bn2bin failed\n\n");    break; } // if  rsapubkey* rsapubkey = (rsapubkey*)(keyblob + sizeof(blobheader));  rsapubkey->bitlen = max_cert_len; rsapubkey->magic = 0x32415352; // 0x0032a400 rsapubkey->pubexp = *public_exponent;  int m1 = rsapubkey->bitlen / 8 + 20;   unsigned int  = 0;  // convert components big endian little endian  for( = 0; < (rsapubkey->bitlen / 8); i++) {     keyblob[m1 - 1 - i] = modulus[i]; } //  int p1 = rsapubkey->bitlen / 16 + m1;  ( = 0; < ( rsapubkey->bitlen / 16 ); i++ ) {     keyblob[p1 - 1 - i] = prime1[i]; } //  int p2 = rsapubkey->bitlen / 16 + p1;  for( = 0; < (rsapubkey->bitlen / 16); i++) {     keyblob[p2- 1 - i] = prime2[i]; } //  int e1 = rsapubkey->bitlen / 16 + p2;  for( = 0; < (rsapubkey->bitlen / 16); i++) {     keyblob[e1 - 1 - i] = exponent1[i]; } //  int e2 = rsapubkey->bitlen / 16 + e1;  ( = 0; < ( rsapubkey->bitlen / 16 ); i++) {     keyblob[e2 - 1 - i] = exponent2[i]; } //  int c1 = rsapubkey->bitlen / 16 + e2;  ( = 0; < (rsapubkey->bitlen / 16); i++ ) {     keyblob[c1 - 1 - i] = coefficient[i]; } //  int d1 = rsapubkey->bitlen / 8 + c1;  ( = 0; < (rsapubkey->bitlen / 8); i++ ) {     keyblob[d1 - 1 - i] = private_exponent[i]; } //  /*     fyi     struct _rsapubkey {             dword   magic;                  // has rsa1             dword   bitlen;                 // # of bits in modulus             dword   pubexp;                 // public exponent                                             // modulus data follows     } rsapubkey      ,       struct _publickeystruc {             byte    btype;             byte    bversion;             word    reserved;             alg_id  aikeyalg;     } blobheader, publickeystruc; */     these structures in wincrypt.h(in windows), linux need add manually.. 

here keyblob stored in "keyblob". here working fine. in function how use keyblob crypto operations(using rsa api). lets using rsa_public_encrypt encryption

i believe expected way covert these ...

rsa* rsa = new rsa( ); ...  e = rsa->e; n = rsa->n; p = rsa->p; q = rsa->q; dmp1 = rsa->dmp1; dmq1 = rsa->dmq1; iqmp = rsa->iqmp; 

... byte arrays use bn_num_bytes , bn_bn2bin:

int len, res;  len = bn_num_bytes(n); unsigned char* n_arr = openssl_malloc(len); assert(n_arr != null); res = bn_bn2bin(n, n_arr); assert(res == len);  len = bn_num_bytes(e); unsigned char* e_arr = openssl_malloc(len); assert(e_arr != null); res = bn_bn2bin(e, e_arr); assert(res == len);  ...  openssl_free(n_arr); openssl_free(e_arr); 

note byte arrays big endian.

you need free evp_pkey* , rsa*. 1 in evp_pkey_get1_rsa means reference count on rsa* bumped, needs call rsa_free. 0 means count not incremented, no *_free required.

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lets using rsa_public_encrypt encryption...

use rsa* directly.

rsapubkey* rsapubkey = (rsapubkey*)(keyblob + sizeof(blobheader));

if ms-capi, need reverse byte arrays. not clear me ms-capi.

i'm guessing problem way bn extracted , converted. guess because not clear me trying other "use it".