Help regarding Windows Crypt API's

[CoolPG]

Hi please somebody help me with decoding H225 signalling messages. I am getting the encoded bytes over TCP. I used MSDN sample code of ByteToStr() to convert those byte buffer into Hex string.

Now i need to convert this ASN encoded string into actual H255 signal messages. I'm working on an H323 project.

I found an MSDN article on ASN1 decoding using CryptDecodeMessage() API, but i'm not getting result after trying their sample code.

http://msdn.microsoft.com/en-us/libr...76(VS.85).aspx




Thanks in advance.

[hoxsiew]

I believe the ByteToStr function is only used to show a binary buffer in user-readable format (hex). Are you trying to decrypt the stream before or after calling ByteToStr?

[CoolPG]

Thanks a lot for your response hoxsiew, yes i am geting the readable hex string after calling BytetoStr(). I am trying to decrypt the stream after the call to BytetoStr() and i'm passing in the converted hex string to decrypt.

I dont know whether i am correct or not doing it, since i am very new to ASN1.0 and h323. Moreover there is less detailed description of h225 encoding/decoding available on internet

Thanks for your support, and please help me to find a solution.

[hoxsiew]

I'm not familiar with this particular implementation, but in general, the ByteToStr() is only used to make a human-readable representation of the data. This is so it can be attached to email or other text-based protocols without being scrambled by text conversions or 7-bit ascii pipes. All actual encryption/decryption should be done on the binary stream.