• Auth is a simple, lightweight and safe client-server authentication system. Written in C++11
• Auth features decoupled salt, encryption and network handshaking from implementation.
• Auth is tiny. Header-only.
• Auth is cross-platform.
• Auth is self-contained. No dependencies.
• Auth is zlib/libpng licensed.

int main() {
    auth::session at_client( "joe@doe.com", "sesame", "@pc-workstation" );
    auth::session at_server( "joe@doe.com", "sesame", "@server" );

    // similar sessions, not equal until public_key is assigned
    assert( at_client != at_server );
    at_client.set_public_key( at_server.get_public_key() );
    assert( at_client == at_server );

    // mutate passphrasses
    for( int i = 0; i < rand(); ++i ) {
        at_client.mutate(); assert( at_client != at_server );
        at_server.mutate(); assert( at_client == at_server );
    }

    // debug
    std::cout << at_client << std::endl;
    std::cout << at_server << std::endl;

    std::cout << "All ok." << std::endl;
}

[session:0034FDC0] {
.valid=1
.timestamp=873971735
.id=joe@doe.com;@pc-workstation
.user=joe@doe.com
.pass=3062624283
.public_key=554326941
.passphrase=4017519821
}

[session:0034FD40] {
.valid=1
.timestamp=873971735
.id=joe@doe.com;@server
.user=joe@doe.com
.pass=3062624283
.public_key=554326941
.passphrase=4017519821
}

All ok.

• You can compare sessions for equality and sort them, or insert them in a map.
• Sessions are not equal unless they have same user and passphrase.
• A passphrase is made of pass and public_key.
• A passphrase can mutate on both sides to change encryption on the fly.
• A server can hold different sessions that refer to the same user at the same time, ie when logging from different computers.
• Public keys can be sent thru insecure networks.

• void setup( string name, string pass, [string context], [string public_key] ) @todoc
• void touch() @todoc
• bool is_timedout() const @todoc
• bool is_valid() const @todoc
• void invalidate() @todoc
• void reset() @todoc
• void mutate() @todoc
• void set_user_info( string name, string pass ) @todoc
• string get_user_name() const @todoc
• string get_user_context() const @todoc
• string get_passphrase() const @todoc
• void set_public_key( string public_key ) @todoc
• string get_public_key() @todoc
• size_t get_timestamp(), @todoc

• Implement namespace auth::provider somewhere both in client and server code.
• Check provided sample for a brief reference implementation.

• https://github.com/r-lyeh/vault to handle ARC4 en/decryption.
• https://github.com/r-lyeh/cocoa to handle SHA1/CRC32 hashes.
• https://github.com/r-lyeh/sand to handle time and timestamps.

Check related appendix