ElGamal算法既能用于数据加密也能用于数字签名，其安全性依赖于计算有限域上离散对数这一难题。
密钥对产生办法。首先选择一个素数p，两个随机数, g 和x，g, x < p, 计算 y = g^x ( mod p )，则其公钥为 y, g 和p。私钥是x。g和p可由一组用户共享。
ElGamal用于数字签名。被签信息为M，首先选择一个
SHOW FULL COLUMNS FROM `jrk_downrecords` [ RunTime:0.001330s ]
SELECT `a`.`aid`,`a`.`title`,`a`.`create_time`,`m`.`username` FROM `jrk_downrecords` `a` INNER JOIN `jrk_member` `m` ON `a`.`uid`=`m`.`id` WHERE `a`.`status` = 1 GROUP BY `a`.`aid` ORDER BY `a`.`create_time` DESC LIMIT 10 [ RunTime:0.086826s ]
SHOW FULL COLUMNS FROM `jrk_tagrecords` [ RunTime:0.001680s ]
SELECT * FROM `jrk_tagrecords` WHERE `status` = 1 ORDER BY `num` DESC LIMIT 20 [ RunTime:0.001589s ]
SHOW FULL COLUMNS FROM `jrk_member` [ RunTime:0.000970s ]
SELECT `id`,`username`,`userhead`,`usertime` FROM `jrk_member` WHERE `status` = 1 ORDER BY `usertime` DESC LIMIT 10 [ RunTime:0.003526s ]
SHOW FULL COLUMNS FROM `jrk_searchrecords` [ RunTime:0.000849s ]
SELECT * FROM `jrk_searchrecords` WHERE `status` = 1 ORDER BY `num` DESC LIMIT 5 [ RunTime:0.003981s ]
SELECT aid,title,count(aid) as c FROM `jrk_downrecords` GROUP BY `aid` ORDER BY `c` DESC LIMIT 10 [ RunTime:0.014463s ]
SHOW FULL COLUMNS FROM `jrk_articles` [ RunTime:0.001147s ]
UPDATE `jrk_articles` SET `hits` = 2 WHERE `id` = 383315 [ RunTime:0.011081s ]
