In PHP website development, verification codes can effectively protect our forms from malicious submissions , but if you do not use arithmetic verification codes or Chinese character verification codes, but only use simple alphabetical or numerical verification codes, is such a verification code solution really safe?
Everyone knows that simple numerical or letter verification codes are easy to crack, but arithmetic verification codes or Chinese character verification codes are not easily cracked. Therefore, it is recommended that when using verification codes, try to use arithmetic verification codes or Chinese character verification codes. .
The following are two verification code codes I wrote. Friends who are useful can refer to them:
1. Calculation verification code:
Copy code The code is as follows:
session_start();
header("Content-type: image/png");
$num1 = mt_rand(0,9);//First digit
$num2 = mt_rand(1,9);//Second digit
$type_str = "+-*";//Method string collection
$type = substr($type_str,rand(0,2),1);//Random method
$change = mt_rand(1,3);
if($change==1){
$code = "$num1$type$num2=?";
$result = "$verifyCode=$num1$type$num2;";
eval($result);
$_SESSION['authnum_session'] = $verifyCode;
}elseif($change==2){
$result = "$verifyCode=$num1$type$num2;";
eval($result);
$code = $num1.$type."_=".$verifyCode;
$_SESSION['authnum_session'] = $num2;
}elseif($change==3){
$result = "$verifyCode=$num1$type$num2;";
eval($result);
$code = "_".$type.$num2."=".$verifyCode;
$_SESSION['authnum_session'] = $num1;
}
$im = imagecreate(68,28);
$black = imagecolorallocate($im, 0,0,0);
$white = imagecolorallocate($im, 255,255,255);
$gray = imagecolorallocate($im, 200,200,200);
$red = imagecolorallocate($im, 255, 0, 0);
imagefill($im,0,0,$white);
imagestring($im, 5, 10, 8, $code, $black);
for($i=0;$i<70;$i++) {
imagesetpixel($im, mt_rand(0, 58) , mt_rand(0, 28) , $black);
imagesetpixel($im, mt_rand(0, 58) , mt_rand(0, 28) , $red);
imagesetpixel($im, mt_rand(0, 58) , mt_rand(0, 28) , $gray);
}
imagepng($im);
imagedestroy($im);
?>
2. Chinese character verification code:
Copy code The code is as follows:
session_start();
$ch_str="The first thing is that in the discord, there is a large number of people in the country who need to use domestic products to divide students into students at different ages. Fang Jin's colleagues said in an interview that after the revolution, many children were added to the social network, and the power line of the high-quality long-term party was achieved. The road map of anti-sexuality and anti-body cooperation transforms the content of the new discussion from the current situation of the two talents, such as the corresponding form, thinking, thinking, and practice, to the change of key points, the emphasis on thinking and the internal removal of causes. The daily profit phase is determined by the pressure of the whole group of Qi karma, the fruit period, the level of each base or the monthly hair, then the comparison shows that it is the most external and does not look at the five interpretations of the forest. The head of the rice group only knows four horse recognition However, the article is relatively grammatical and public, leading to the inflow of the receiving seat, and flying crude oil to set up the problem to refer to the construction of the district inspection activity, and many educational decisions have been made. You and Xi Jinping's general information will be re-elected and will be re-elected. Qimoshan Cheng Baibao will see that it is necessary to keep warm and hand over the changes in management. We will repair the symptoms, identify the disease symptoms, and the six types of old light. What are the six types of rehabilitation belts? After finishing the wind, I returned to Nanguang, Lunlun, Kebei, and planned the truck schedule and the work was integrated. The step number was listed, the temperature was installed, and the axis was grinded. The solid color was solid, the speed was reduced, and the Shila Shidaer field was weaved. The calendar flower was requested to be passed on. The oral judgment is collected and the Naga World product is judged and the reference layer is stopped at the border and cleared to Wanquan. The factory must be away from the sea and handed over to the right, and the children's youth talent certificate is low and cross-country. The eight test regulations are not far away. The soldiers are solid, the teeth are eliminated, the teeth are thousands of victors, the fine shadows are Jibai, the effect is set and pushed empty, with the blade rate, the current selection is to raise the virtue, then check the difference, half the enemy, the first film is applied, the sound is collected, the Huajue is named, the red is added, the uniform medicine mark is difficult to save, and the body of the soldier is measured. Tight liquid system, accurate weight angle, dimension reduction board, Xu broken technology, bottom bed field potential end sense, Hecun construction, appearance, non-engagement, Yamo family fire section, suitable value, beautiful appearance, Huang Yibiao, morning shift wheat cutting letter row Taiwan's voice should attack Zhang Mi, harm Houcao, He Shufei, follow the right city's strict path and snail inspection, left page, resist Su Xian's bitter British, quickly say bad move, Heiwu Pei Zhu, Yorbachi Province, only needle, how to plant the capital to help the king's eye She catches the seedlings and vice versa and talks about surrounding food radioactive sources causing sourness and old but sufficient short strokes. Teacher Li Qu Chunyuan Super Negative Sand Sealing Change Taimo Poverty Reduction Yangjiang Analysis Mu Mu Yan Qi Chao Medical School Gu Ni Dao Song Ting Wei Shu Hua Station Another Wei Zi Gu Gang Wrote Liu Wei Lue Fan Gong A Kuai A Certain Kung Fu Set Friend limit item Yu rewinds and creates law rain, lets Gu Yuan help Chu Pibo to occupy the dead poison circle, Wei Ji training and control stimulates, calls the clouds, and cracks the grain grain master practice, plugs the steel top policy, doubles the wrong base, sucks the block, so the shield is late. Silk girl scattered welding power Zhu pro-in hospital cold and thorough bombing scattered business visual art destroyed edition Lie zero room light blood times lack of Li pump inspection Juefu city flushing soil Jian Fuzhu Li Wangpan magnetic male seems to be trapped Gong Yizhou takes off the delivery slave side run cover Swing the distance, touch the star, and send him to the independent official. The discipline has not yet emerged. The wide winter chapter is wet and partial. The boss is responsible for the mine village. The responsibility is mature and the hard price is guaranteed. Nufeng Qijia pre-job evaluation is read. The back is damaged and the cotton is invaded by dust. Although the spear is thick. Luo Nipi sued the egg box, palm oxygen, love, stopped, dissolved camp, ended up with Meng Qian waiting to be exhausted, Russia shrunk, sand retreated, Chen challenged the equipment to carry the young, which exploited the rotary levy slot, held the shoulder, still ah, fresh bar card, rough introduction, drilled and chased the weak foot. Afraid of the end of salt, Yin Feng, compiled by bees, rushed to expand the wound, exposed the core edge, traveled, vibrated, and vibrated in the central five areas, very fast, out of sequence, paper-free, night town, long-term servitude, cylinder clip, read Lan Yinggou B? Make up for the yong tiles, the carbon performance, the teeth, the yong tiles, the oblique irrigation, the European and shun pigs, the foreign rots, please pass through the Si Wei Kuo pulse, it is good to smile, if the tail bunch is strong, the vegetable ears, Chu Han Yu, the green, drag the cattle, dye them all over the autumn, forge the jade summer. Healing the tip of the well, Feizhou, visiting, blowing the bronze edge, calling for rolling guests, summoning the drought, enlightening the mind, piercing the brain, passing through the Tibet, dare to order the gap, the furnace shell, the sulfur coal, welcome the cast and stick, explore the thin ten days, good fortune, indulge in the rituals, wish to subdue the residual thunder, and extend the smoke, pure and gradual Farming, running, slowly planting, Lu Chifan's realm, the tide crossed, Xichi, the ship was destroyed, falsely said, entrusted Huo Zhehuai, cut tribute, presented strong wealth, rituals, heavy refining, sin, ancestors rested, chariots were worn, goods were sold, rats were drawn, dragons were kept, and warehouses were built. Fangge Hanxi, brother washes away the waste and takes in the belly. He records the mirror, the woman is evil, the village wipes the risk, praises the bell, shakes the handle, debates the bamboo valley, sells the chaos, the bridge, Ober, rushes to the vertical road, the forehead wall, cuts off the wild remains, plots, hangs the class, suppresses the madness, and endures. Aid Zha, consider the key, return to Fuqing, gather around the mo, dance in a hurry, encounter the rope, Gu Jiaoyang Lake, nail kernel, broken sound track, stretch out the lamp, avoid flood, die, answer bravely, Huang Liuhajie, Gannuogai, Xian Nong Island, who is attacked by flood, cannon pouring, information, understanding spirit egg Close the child and release the breast, the giant private banker, Yi Jingtan, tired uniform mold, Du Lele, separated by the curve, Zhao Shao, Hu Hutongfeng, Ling Chai Spring Wu, jumped to Shang Ding, Qin Shao, chased the beam, broke the alkali, special hill, dug the blade, drama, hehe chest. The Hengqin film article was published in the case publication. It's ridiculous to paint Wei Jin's arms, brown land, Jianzun Doubamo, Sangpo's sewing police pick on the ice and Cambodian mouth, what kind of rice plastic is sent to Zhao Mingpad, Kang Zunmu, was cheated by the garden-tongued flesh brother Wu Minhui, who forgot his clothes, Sun Linling, cheated and borrowed. Dandu's ears are shaved, tiger's pen is thin, Kunlang Sa's tea drops are shallow, her cunt is covered with Lun Niang's tons of sleeve beads, her mother's purple opera tower is hammered, she is old, her appearance is clean, she is in prison, and she is suspicious of the bully. Sinking, melting, chlorine, barren stems, men who snatch the pulp, are loyal, sing, and catch the locks. You take advantage of Wu Zhidan and allow the traitorous livestock prisoners to touch the rust and sweep the glass. Zhu Liken Liquor Rope Poor Pond Dry Bubble Bag Lang Feeding Aluminum Soft Canal Habitual Trade Feces Comprehensive Wall Trending Mo Obstruction Kai Reversing Unloading Navigation Fog Crown Bing Street Laibei Radiation Intestine "Tang Sheng's concave pottery poem Chi Can Yi Ju";
$len = mb_strlen($ch_str,"utf-8");//Chinese character length
$str = array();
for($i=0;$i<4;$i++){
$pos = mt_rand(0,$len-5);//Starting position
$str[] = mb_substr($ch_str,$pos,1,"utf-8");
}
$authnum_session = implode("",$str);
$_SESSION['authnum_session'] = $authnum_session; //Record to session
Header("Content-type: image/PNG");
//The length and height of the picture
$image_x=100;
$image_y=50;
$im = imagecreate($image_x,$image_y);
//The background color of the picture here is white
$bkg = ImageColorAllocate($im,255,255,255);
//Displayed font style, this requires placing the file in the corresponding directory. If you don't have a file, go find one in the window's font file.
$fnt = "simhei.ttf";
//Assign some color to the image
$white=ImageColorAllocate($im,234,185,95);
//Draw an elliptical arc on the picture and specify the lower coordinate point
imagearc($im, 150, 8, 20, 20, 75, 170, $white);
imagearc($im, 180, 7,50, 30, 75, 175, $white);
//Draw a line segment on the picture and specify the lower coordinate point
imageline($im,20,20,180,30,$white);
imageline($im,20,18,170,50,$white);
imageline($im,25,50,80,50,$white);
//The number of random points
$noise_num=3000;
$line_num=50;
//Color of various confusing characters
$rectangle_color=imagecolorallocate($im,0xAA,0xAA,0xAA);
$noise_color=imagecolorallocate($im,0x00,0x00,0x00);
$font_color=imagecolorallocate($im,0x00,0x00,0x00);
for($i=0;$i<$noise_num;$i++)
{
//Draw a single pixel on a coordinate point. This point is defined above and is black.
//imagesetpixel($im,mt_rand(0,$image_x),mt_rand(0,$image_y),$noise_color);
}
for($i=0;$i<$line_num;$i++)
{
$line_color=imagecolorallocate($im,mt_rand(0,255),mt_rand(0,255),mt_rand(0,255));
//Draw a line between two coordinate points, the color is defined above
Imageline($im,mt_rand(0,$image_x),mt_rand(0,$image_y),mt_rand(0,$image_x),mt_rand(0,$image_y),$line_color);
}
for ($i=0;$i<4;$i++)
{
ImageTTFText($im, rand(18,20), rand(0,20), rand(($image_x/4)*$i+$image_x/100,($image_x/4)*$i+$image_x/8), rand($image_y/2+$image_y/10,$image_y/2+$image_y/5), $font_color, $fnt, $str[$i]);
}
ImagePNG($im);
ImageDestroy($im);
?>
Font file: simhei.rarClick here to download from this site.
Note:
Execute the Chinese character verification code separately, and then obtain the session and you will find that the verification code and session content are inconsistent. However, when the Chinese character verification code file is referenced in the src attribute in the img tag, and then the session is obtained, the contents of the two are consistent.
Interested friends can further improve this.
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