Since games are played clearly in email in the club, when we are talking about serious things (such as emailchess), the problem of security sometimes crops up.
Nowadays it's not impossible that somebody writes an email message in the name of somebody else, or catches an email during its path and changes its content. When there is a lot at stake, this danger can not left unspoken.
Digital signatures solve this problem. Using them ensures that an incoming message could only be originated by its sender and its content could not be altered during the transfer.
The most widely used is the PGP (Pretty Good Privacy) based public key digital signature system. This is supported in the club by the chess server also.
All the registered players can turn on and off that the server should digitally sign all messages it sends to them. The players get the server's public key (listed bellow) and with it they can verify if the message they received was really created by the server and its content is not altered.
Players can also turn on that the server should accept only digitally signed messages from them. This way they can be sure that nobody can send commands in their name and nobody can alter the message content they composed. If the signature is missing or invalid the server refuses to execute the message and sends back an error report. This also works with players who play from more email addresses.
Using digital signatures requires specific software to be installed on the players' machine that supports PGP based digital signing and verification. Freeware versions also exist out there, for example here: http://www.pgpi.org
But of course, no one should worry about privacy here, since sending an email message in somebody else's name or forging one requires high knowledge level. Those people are threatened in it who deal with really serious things.
In my opinion emailchess doesn't really belong to these very serious things. By all means the possibility is given to use digital signatures.
Here is the public key block that belongs to the email@example.com email address, or it can be downloaded from here: http://firstname.lastname@example.org
-----BEGIN PGP PUBLIC KEY BLOCK----- Version: PGP 7 mQGiBD5GkB0RBADDELcUOoO8U9yEiHyUT8vXCSPRyuu0yFlvxEUeGrTwLgAJe3ju e/sCcwy0sMK/Spl0Arrei+qa0CSOcdf4LS2m6FrkdPHVLpHPp2nneZwqybUY+vbO O3AcFG50W25xMvAA/CPcNihASJ//tFa7GOwHaW9Sa2L4gczi2Lugcxe+EQCg/wxk ol90Fv8pN3DkVxGNsSUQuesEAJmKdpb1zyXUWQN22iTpx5EvvSQ6HRWypMpZT8lE JQltbq1/cSVGgPAmQmHrh6EOly/L48nEWcrNh4hne4EyU3lKIPmkB1kbi1vvZBze LMGvjk/ZxTtAGmZ1u5WCoe2jhCVudLLDFeT/iRUO1dWsKeMoe7GrqGLQyUop0IND cswBA/9Btgnf7AHRijfZ5013wY/0mIAPlERrpJb5+dCuNE8wew9RFUC/P4uM4MU4 fJ0VDa2A7a0OeNHmKpd+HaBEeRglDgwt89wjQtvRtUTqte1rDEvWbNQYt1UWTXZT MgNf0IA8irM0sPiBo+yylEpFaxoNS0M9lajBuMVIlS8TCHB1nLQfY2hlc3NAZTRl Yy5vcmcgPGNoZXNzQGU0ZWMub3JnPokAWAQQEQIAGAUCPkaQHQgLCQgHAwIBCgIZ AQUbAwAAAAAKCRAzfy8kxtPs1a0yAKDzTHPsrErFNsFKQrq2sczKdATsyQCfbvt5 695L8QNWwvkMi1JWUJiOlpK5Ag0EPkaQHRAIAPZCV7cIfwgXcqK61qlC8wXo+VMR OU+28W65Szgg2gGnVqMU6Y9AVfPQB8bLQ6mUrfdMZIZJ+AyDvWXpF9Sh01D49Vlf 3HZSTz09jdvOmeFXklnN/biudE/F/Ha8g8VHMGHOfMlm/xX5u/2RXscBqtNbno2g pXI61Brwv0YAWCvl9Ij9WE5J280gtJ3kkQc2azNsOA1FHQ98iLMcfFstjvbzySPA Q/ClWxiNjrtVjLhdONM0/XwXV0OjHRhs3jMhLLUq/zzhsSlAGBGNfISnCnLWhsQD GcgHKXrKlQzZlp+r0ApQmwJG0wg9ZqRdQZ+cfL2JSyIZJrqrol7DVekyCzsAAgII ANxSR3IhxluqJgQlAqZ5xY/fZudaY+3mKcXFvxRdwX4FgqWLmxme+P4mGgD/plAt Hxnt0BEikpEx7SPd4xPcZ5WKarWAdrsf8E+keUUHVhjRvXhNkfSJWk66gIuK4XiK e5SkeHs0THFCmoj2thhowFTEMCk4O1+SjkJTLmHcE1wamLS22WpjphrTyuWbYatH rgfchDns9H5Njzw3zmGpEQXg0fNQ6RnTsg+fsBlhD0h3cX77n5NfI7p+msBDi+cI ft3sImQ/5MVd7D3WuUSjAfCc+zst02AEMn9aeINrPhJzHzELitVhUsQaf7iUbX+N svC4JVQ5nq6c7DsyZvzb8MSJAEwEGBECAAwFAj5GkB0FGwwAAAAACgkQM38vJMbT 7NVg6wCg6v67g+CmYL4S5mKDePNTH84WuqIAoIh2wy5Xd0rIWQ0EGAKkf2FQEmo0 =dEUf -----END PGP PUBLIC KEY BLOCK-----
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