sorry, I misunderstand your request " for internal processing". the previous functions which I memtioned can't be processing.
I think this will be better. RSA *pub_key = NULL; pub_key = readPublicKey(); // to read a public key from a file ,you can use your own function to get a rsa object BIO *mem = BIO_new(BIO_s_mem()); RSA_print(mem,pub_key,0); unsigned char buf[1024*10]; BIO_read(mem,buf,1024*10); printf("%s \n",buf); BUF_MEM *bio_buf=NULL; BIO_get_mem_ptr(mem,&bio_buf); I recommend you to use a memory BIO to store the rsa data. You can use it like a common BIO or you can get it's internal string use BIO_get_mem_ptr. At 2011-01-13 03:34:32,"Muneeswaran Raju" <hieswar...@gmail.com> wrote: Hi, I am able to generate the RSA private keys by "RSA_generate_key_ex". I need to store it into a buffer for internal processing. Can you please suggest me to convert RSA a key into buffer. I had seen the examples to dump into file. Instead of file processing I need to convert RSA private key into buffer. Thanks Muneeswaran.R