When PHP processes a hash string, it uses "! =" or "= =" to compare the hash value, which interprets each hash value starting with "0E" as 0, so if two different passwords are hashed and their hashes start with "0E", then PHP will think they are the same, and they are all 0. Detailed description of PHP hash comparison: http://www.freebuf.com/news/67007.html 0x01 MD5 (str) qnkcdzo0e830400451993494058024219903391 s878926199a0e545993274517709034328855841020 s155964671a0e342768416822451524974117254469 s214587387a0e848240448830537924465865611904 s214587387a0e848240448830537924465865611904 s878926199a0e545993274517709034328855841020 s1091221200a0e940624217856561557816327384675 s1885207154a0e509367213418206700842008763514 s1502113478a0e861580163291561247404381396064 s1885207154a0e509367213418206700842008763514 s1836677006a0e481036490867661113260034900752 s155964671a0e342768416822451524974117254469 s1184209335a0e072485820392773389523109082030 s1665632922a0e731198061491163073197128363787 s1502113478a0e861580163291561247404381396064 s1836677006a0e481036490867661113260034900752 s1091221200a0e940624217856561557816327384675 s155964671a0e342768416822451524974117254469 s1502113478a0e861580163291561247404381396064 s155964671a0e342768416822451524974117254469 s1665632922a0e731198061491163073197128363787 s155964671a0e342768416822451524974117254469 s1091221200a0e940624217856561557816327384675 s1836677006a0e481036490867661113260034900752 s1885207154a0e509367213418206700842008763514 s532378020a0e220463095855511507588041205815 s878926199a0e545993274517709034328855841020 s1091221200a0e940624217856561557816327384675 s214587387a0e848240448830537924465865611904 s1502113478a0e861580163291561247404381396064 s1091221200a0e940624217856561557816327384675 s1665632922a0e731198061491163073197128363787 s1885207154a0e509367213418206700842008763514 s1836677006a0e481036490867661113260034900752 s1665632922a0e731198061491163073197128363787 S878926199A0E5459932745177090343288558410200X02 MD5 (MD5 ()) 0x03 MD5 (MD5 (STR). " SALT ") 20e774261293712168181959463563504
PHP handles 0e start MD5 hash string defect/bug