[原文]The CheckGroup function in openSkat VTMF before 2.1 generates public key pairs in which the "p" variable might not be prime, which allows remote attackers to determine the private key and decrypt messages.
OpenSkat contains a flaw that may allow a malicious user to crack the encryption built into the game. The issue is due to the fact that the CheckGroup() function does not properly ensure that the variable "p" contains a number which is prime, leading to a weak cryptographic key. It is possible that the flaw may allow decryption of game information, resulting in a loss of confidentiality.
Upgrade to version 2.1 or higher, as it has been reported to fix this vulnerability. An upgrade is required as there are no known workarounds.