Create your array of values, in your .m file or before the @interface in your .h file, like this:
static const UInt8 encryptionKey[] = {0x01, 0x02, 0x03, 0x04, 0x05,
0x06, 0x07, 0x08, 0x09};
Use it like this
= encryptionKey[1];
while (offset >= (sizeof(encryptionKey) / sizeof(UInt8)))
offset -= (sizeof(encryptionKey) / sizeof(UInt8));