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Question:

SSH Encryption and MAC used ?

Dec 17 '14 at 14:15

How can I find out what encryption and MAC is actually beingg used by a connection ? The sessionlog lists several; whic one is the connection actually using ?

TRAN* Established TCP/IP connection with SSH server
TRAN> SSH-2.0-PuTTY_Local:_May_14_2009_21:12:18
TRAN< SSH-2.0-IPSSH-6.8.0
TRAN> KEXINIT
TRAN< KEXINIT
TRAN* Key Algorithms: diffie-hellman-group14-sha1,diffie-hellman-group1-sha1
TRAN* Host Key Algorithms: ssh-rsa,ssh-dss
TRAN* Out Encryption: aes128-cbc,aes192-cbc,aes256-cbc,blowfish-cbc,cast128-cbc,3des-cbc,des-cbc,des-cbc,arcfour128,arcfour
TRAN* In Encryption: aes128-cbc,aes192-cbc,aes256-cbc,blowfish-cbc,cast128-cbc,3des-cbc,des-cbc,des-cbc,arcfour128,arcfour
TRAN* Out MAC: hmac-sha1,hmac-sha1-96,hmac-md5,hmac-md5-96
TRAN* In MAC: hmac-sha1,hmac-sha1-96,hmac-md5,hmac-md5-96
TRAN* Out Compress: none
TRAN* In Compress: none
TRAN> KEXDH_INIT
TRAN< KEXDH_REPLY
TRAN* DSS signature verified
TRAN> NEWKEYS
TRAN< NEWKEYS
TRAN* SSH Key Exchange Success.
TRAN> IGNORE

Answer

I will make this easy to obtain from the LastErrorXml. What is the exact build that you would need? (Programming language, operating system, .NET Framework, VC++ version, Perl version, etc.)

Answer

I am targeting .NET Framework 4.0, C#.

Answer

In the new build (starting with v9.5.0.47) the LastErrorXml after calling Connect, will contain XML nodes like this: 

    <ChosenIncomingEncryption>aes256-ctr</ChosenIncomingEncryption>
    <ChosenOutgoingEncryptoin>aes256-ctr</ChosenOutgoingEncryptoin>
    <ChosenIncomingMac>hmac-sha2-256</ChosenIncomingMac>
    <ChosenOutgoingMac>hmac-sha2-256</ChosenOutgoingMac>
    <ChosenIncomingCompression>zlib@openssh.com</ChosenIncomingCompression>
    <ChosenOutgoingCompression>zlib@openssh.com</ChosenOutgoingCompression>
    <ChosenKexAlgorithm>diffie-hellman-group-exchange-sha256</ChosenKexAlgorithm>
    <ChosenHostKeyAlgorithm>ssh-dsa</ChosenHostKeyAlgorithm>

Answer

Thanks! When will v9.5.0.47 be available ?

Answer

Here are the new builds:

32-bit Download: http://www.chilkatsoft.com/download/preRelease/ChilkatDotNet4-9.5.0-win32.zip

64-bit Download: http://www.chilkatsoft.com/download/preRelease/ChilkatDotNet4-9.5.0-x64.zip

Answer

Thanks again. The LastErrorText/Xml/Html indeed contains the information on the chosen ciphers, etc.

I went back to v9.3 that I had been using, and it also has this information. Does that make sense ?