T. Horsten explained the size limits on raw encryption. Here are two functions to encrypt/decrypt larger data when you can't use the envelope functions:
function ssl_encrypt($source,$type,$key){
//Assumes 1024 bit key and encrypts in chunks.
$maxlength=117;
$output='';
while($source){
$input= substr($source,0,$maxlength);
$source=substr($source,$maxlength);
if($type=='private'){
$ok= openssl_private_encrypt($input,$encrypted,$key);
}else{
$ok= openssl_public_encrypt($input,$encrypted,$key);
}
$output.=$encrypted;
}
return $output;
}
function ssl_decrypt($source,$type,$key){
// The raw PHP decryption functions appear to work
// on 128 Byte chunks. So this decrypts long text
// encrypted with ssl_encrypt().
$maxlength=128;
$output='';
while($source){
$input= substr($source,0,$maxlength);
$source=substr($source,$maxlength);
if($type=='private'){
$ok= openssl_private_decrypt($input,$out,$key);
}else{
$ok= openssl_public_decrypt($input,$out,$key);
}
$output.=$out;
}
return $output;
}
