/**
* converts keypair to PEM-encoded string, which can be stroed in
* .pem compatible files, contianing RSA private key.
*
* @return string PEM-encoded keypair on success, false on error
* @access public
*/
function toPEMString()
{
// store RSA private key attributes into ASN.1 string
$str = '';
$attr_names = $this->_get_attr_names();
$n = sizeof($attr_names);
$rsa_attrs = $this->_attrs;
for ($i = 0; $i < $n; $i++) {
$attr = $attr_names[$i];
if (!isset($rsa_attrs[$attr])) {
$this->pushError("Cannot find value for ASN.1 attribute [{$attr}]");
return false;
}
$tmp = $rsa_attrs[$attr];
$str .= Crypt_RSA_KeyPair::_ASN1StoreInt($tmp);
}
// prepend $str by ASN.1 SEQUENCE (0x10) header
$str = Crypt_RSA_KeyPair::_ASN1Store($str, 0x10, true);
// encode and format PEM string
$str = base64_encode($str);
$str = chunk_split($str, 64, "\n");
return "-----BEGIN RSA PRIVATE KEY-----\n{$str}-----END RSA PRIVATE KEY-----\n";
}
