obfuscated-openssh | first step in the obfuscation protocol | Cryptography library

obfuscated-openssh is a C library typically used in Security, Cryptography applications. obfuscated-openssh has no bugs, it has no vulnerabilities and it has low support. However obfuscated-openssh has a Non-SPDX License. You can download it from GitHub.

The first step in the obfuscation protocol is that the client connects to a port running the protocol and sends a seed message which is used to derive the keys for obfuscating the handshake. #define OBFUSCATE_MAGIC_VALUE 0x0BF5CA7E #define OBFUSCATE_SEED_LENGTH 16 #define OBFUSCATE_MAX_PADDING 8192. [ 16 byte random seed ][ magic ][ plength ][ .. plength bytes of random padding ... ] |||___________________________| | | Plaintext Encrypted with key derived from seed. To create the seed message the client first generates 16 pseudo random bytes from which the handshake obfuscation keys will be derived. The client also runs the key derivation algorithm (described below) to initialize the obfuscation cipher. The 'magic' field and the 'plength' field are 32 bit unsigned values transfered in network byte order (MSB first). The magic field must contain the constant OBFUSCATE_MAGIC_VALUE and the 'plength' field must contain a randomly selected value between 0 and OBFUSCATE_MAX_PADDING. Then 'plength' bytes of pseudo randomly generated data is appended after the length field. The purpose of the padding is to prevent a trivial traffic analysis attack which allows the protocol to be identified my merely observing the size of the first message. Upon receiving the seed message from the client, the server must extract the seed bytes and perform the key derivation algorithm (described below) before decrypting the rest of the message. Then the server must verify that the magic value is correct and also that the padding length is below OBFUSCATE_MAX_PADDING. If these checks fail the server will continue reading and discarding all data until the client closes the connection without sending anything in response.