[OTR-dev] A C# lib

[alex323]

(Sorry if I did this wrong, i'm still getting my feet wet with this 
mailing list thing)
Should we start a sourceforge project on the entire OTR project? This 
could include lib-otr, gaim-otr, my C# lib.. and anything else you want 
to include. What do you think? I can do all the registration if you'd 
like (the hard stuff).

Ian Goldberg wrote:

>On Sat, Jan 15, 2005 at 12:55:18AM -0500, alex323 wrote:
>  
>
>>As you might have heard, I'm making a libary in C# for OTR.
>>    
>>
>
>Wow.  That's awesome.  [Not to mention that it's super-useful to have
>interoperable implementations of a protocol.]
>
>  
>
>>I have a few questions however regarding the protocol:
>>
>>* What is the size of the DH key I need to generate? (I don't think it's 
>>1536.. I tried it)
>>* I have two editable parameters with my DH class: P and G. Should G be 
>>set to 0x02 and P should be set to the key you generated?
>>    
>>
>
>  - DH y (MPI)
>    - The initial DH public encryption key.  The DH group is the one
>      defined in RFC 3526 with 1536-bit modulus (hex, big-endian):
>            FFFFFFFF FFFFFFFF C90FDAA2 2168C234 C4C6628B 80DC1CD1
>            29024E08 8A67CC74 020BBEA6 3B139B22 514A0879 8E3404DD
>            EF9519B3 CD3A431B 302B0A6D F25F1437 4FE1356D 6D51C245
>            E485B576 625E7EC6 F44C42E9 A637ED6B 0BFF5CB6 F406B7ED
>            EE386BFB 5A899FA5 AE9F2411 7C4B1FE6 49286651 ECE45B3D
>            C2007CB8 A163BF05 98DA4836 1C55D39A 69163FA8 FD24CF5F
>            83655D23 DCA3AD96 1C62F356 208552BB 9ED52907 7096966D
>            670C354E 4ABC9804 F1746C08 CA237327 FFFFFFFF FFFFFFFF
>      and generator 2.
>
>So yes, it's 1536 bits.  G = 0x02, and P is the above 1536-bit modulus.
>(We didn't generate it; it's the standard one from RFC 3526.)
>
>  
>
>>What about the DSA key length?
>>    
>>
>
>1024 bits (the largest the standard allows).
>
>  
>
>>* Why doesn't the protocol say that you need to include a NULL (byte 0) 
>>as the first character of the key exchange message?
>>    
>>
>
>Well, the first field of the Key Exchange Message (after base64-decoding) is:
>
>  - Protocol version (SHORT)
>    - The version number of this protocol is 0x0001.
>
>So that'd be encoded as \x00\x01.  Is that the NUL you're talking about?
>
>  
>
>>* Why is there an 'e' in the DSA key? My only options are P, Q, G, Y, 
>>and X. Wikipedia told me that X was the private key.
>>    
>>
>
>'e' == 'Y'.  There was this problem that 'Y' was already used by the DH
>key in the Key Exchange Message.  X is indeed the private key [which of
>course never gets sent in the protocol ;-) ]
>
>  
>
>>Thanks in advance for your answer(s).
>>    
>>
>
>No problem.
>
>   - Ian
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>
>  
>