class Letter:
    sign = "计算得到"
    encryptType = "SM4-GCM"
    encryptKey = "计算获得" # recvPubKey 加密后的 对称加密秘钥 数据
    recvPubKey = ""
    senderPubKey = ""

    fileName = ""
    fileSize = 0
    fileBase64 = ""