Classic PHP encryption and decryption function Authcode () fixed version code _ PHP Tutorial

The classic PHP encryption and decryption function Authcode () fixes the code. Classic PHP encryption and decryption function Authcode () fixed version code Authcode this function is used by many people, this function is from the Discuz program, used to encrypt and decrypt strings, you can set the key) and the classic PHP encryption and decryption function Authcode () fix version code

Many people use the Authcode function. this function comes from the Discuz program and is used to encrypt and decrypt strings. it can be used to set the key and Expiration Time. The original function code may generate characters such as +,/, and &. as a result, the function code is escaped when the value is retrieved through the URL and cannot be decrypted. The network on the fire end is slightly modified. replace these characters with other characters, and then replace them with each other during decryption. this is perfect!

The code is as follows:

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Function authcode ($ string, $ operation = 'Decode', $ key = '', $ expiry = 0 ){ If ($ operation = 'decode '){ $ String = str_replace ('[a]', '+', $ string ); $ String = str_replace ('[B]', '&', $ string ); $ String = str_replace ('[c]', '/', $ string ); } $ Ckey_length = 4; $ Key = md5 ($ key? $ Key: 'livcmsencryption '); $ Keya = md5 (substr ($ key, 0, 16 )); $ Keyb = md5 (substr ($ key, 16, 16 )); $ Keyc = $ ckey_length? ($ Operation = 'decode '? Substr ($ string, 0, $ ckey_length): substr (md5 (microtime (),-$ ckey_length )):''; $ Cryptkey = $ keya. md5 ($ keya. $ keyc ); $ Key_length = strlen ($ cryptkey ); $ String = $ operation = 'decode '? Base64_decode (substr ($ string, $ ckey_length): sprintf ('% 010d', $ expiry? $ Expiry + time (): 0). substr (md5 ($ string. $ keyb), 0, 16). $ string; $ String_length = strlen ($ string ); $ Result = ''; $ Box = range (1, 0,255 ); $ Rndkey = array (); For ($ I = 0; $ I <= 255; $ I ++ ){ $ Rndkey [$ I] = ord ($ cryptkey [$ I % $ key_length]); } For ($ j = $ I = 0; I I <256; $ I ++ ){ $ J = ($ j + $ box [$ I] + $ rndkey [$ I]) % 256; $ Tmp = $ box [$ I]; $ Box [$ I] = $ box [$ j]; $ Box [$ j] = $ tmp; } For ($ a = $ j = $ I = 0; $ I <$ string_length; $ I ++ ){ $ A = ($ a + 1) % 256; $ J = ($ j + $ box [$ a]) % 256; $ Tmp = $ box [$ a]; $ Box [$ a] = $ box [$ j]; $ Box [$ j] = $ tmp; $ Result. = chr (ord ($ string [$ I]) ^ ($ box [($ box [$ a] + $ box [$ j]) % 256]); } If ($ operation = 'decode '){ If (substr ($ result, 0, 10) = 0 | substr ($ result, 0, 10)-time ()> 0) & substr ($ result, 10, 16) = substr (md5 (substr ($ result, 26 ). $ keyb), 0, 16 )){ Return substr ($ result, 26 ); } Else { Return ''; } } Else { $ Ustr = $ keyc. str_replace ('=', '', base64_encode ($ result )); $ Ustr = str_replace ('+', '[a]', $ ustr ); $ Ustr = str_replace ('&', '[B]', $ ustr ); $ Ustr = str_replace ('/', '[c]', $ ustr ); Return $ ustr; } }

The Authcode function is used by many people. this function comes from the Discuz program and is used to encrypt and decrypt strings. you can set keys and...