openssl_private_encrypt() returns false with output of 0

Question

I am trying to use the PHP function openssl_private_encrypt() to encrypt an uploaded file prior to saving it (see code snippet below), however it\'s bool is returning false and

Answer 1

I'm not sure about PHP but in C/C++(OpenSSL) asymmetric encryption(RSA mainly) works on data with length less than the key size. And normally it is used to encrypt hash values. If you want to encrypt large(more the ~256 bytes)amount of data you'd better use some symmetric(block) cipher like AES or TriDES. Symmetric ciphers are much faster by the way.

PS Sorry I don't have enough reputation to put this post into comments.