reserve a few more bits for future cipher modes

#define		EVP_CIPH_CBC_MODE		0x2

#define		EVP_CIPH_CFB_MODE		0x3

#define		EVP_CIPH_OFB_MODE		0x4

#define 	EVP_CIPH_MODE			0x7

#define 	EVP_CIPH_MODE			0xF0007

/* Set if variable length cipher */

#define 	EVP_CIPH_VARIABLE_LENGTH	0x8

/* Set if the iv handling should be done by the cipher itself */