Use random_bytes instead of mt_rand for sessionCreateId #46
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According to https://www.php.net/manual/function.mt-rand.php, mt_rand "must not be used for cryptographic purposes". But according to the source code: https://github.com/php/php-src/blob/e72b6f471aaabafc35ee5f7e1259ebd441da7d66/ext/random/engine_mt19937.c#L240 the default seed is generated by random_bytes, so it is secure to use mt_rand together with mt_srand. However, since mt_srand uses random_bytes, it makes more sense to just use random_bytes instead, which is secure according to the documentation without need to investigate the source code. This commit also makes the session ID longer to contain more entropy.
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According to https://www.php.net/manual/function.mt-rand.php, mt_rand "must not be used for cryptographic purposes". But according to the source code: https://github.com/php/php-src/blob/e72b6f471aaabafc35ee5f7e1259ebd441da7d66/ext/random/engine_mt19937.c#L240 the default seed is generated by random_bytes, so it is secure to use mt_rand together with mt_srand. However, since mt_srand uses random_bytes, it makes more sense to just use random_bytes instead, which is secure according to the documentation without need to investigate the source code.
This commit also makes the session ID longer to contain more entropy.
mt_sranduses 4 random bytes instead of 8, so if this little performance is required we can also change torandom_bytes(4)instead.See also: walkor/workerman@c2dde2e