reversing

Sending messages to objects while debugging Objective-C in gdb, without symbols.

I'm trying to send messages to Objective-C objects in gdb. (gdb) p $esi $2 = (void *) 0x1268160 (gdb) po $esi <NSArray: 0x1359c0> (gdb) po [$esi count] Target does not respond to this message selector. I can't send any message to it. Am i missing something? Do I really need the symbols, or something else? Thanks in advance! ...

direct show source filter debug

i have direct show source filter which i'd like to know what it does internaly. it is skystar2 card sdk dshow source filter, id' like to know how does it get stream of data from pci card driver and how it comunicates with it , how can i debug or reverse thiS? ...

Identifying algorithm used to generate codes

How would one identify what algorithm is used to generate codes with? Both common, open source ones, and the more difficult, custom unpublished algorithms? For example here are a sample... x3vbhzcouy g3zy453f4 srix1gtvri 3ewnubic5vz 4bu9ksba6yj r1u3rxfd82n fs30bew9eq b8gr8w5f3 tz6t998ulr ycd1zued oizyviwv 7w6eownv0 s15zxpid9uoo u8is4ulx...

What's a good method/function to create a reversible hash?

I need to transmit some data over the wire and I don't want that data being plain text. The text I'm sending needs to be reversed so I can't md5/sha256/etc... What's a good way to encode a salted string? ...