C # The most practical string encryption and decryption Methods

Using System; using System. data; using System. configuration; using System. web; using System. web. security; using System. web. UI; using System. web. UI. webControls; using System. web. UI. webControls. webParts; using System. web. UI. htmlControls; using System. IO; using System. security. cryptography; using System. text; namespace SQL _function {// <summary> // All encryption methods // define the string encryption interface [MD5 encryption, SHA1 encryption, string encryption] defined in the foreground as follows: /// SQL _fu Nction. interFaceStringEncryptionDecryption QueryStringEncodeCodeAndDncodeCode = new SQL _function.StringEncryptionDecryption (); // description: SQL _function represents the namespace name InterFaceStringEncryptionDecryption represents the interface name StringEncryptionDecryption represents the class name // </summary> publicinterfaceInterFaceStringEncryptionDecryption {# region (1) queryString encryption and decryption start /// <summary> // QueryString encryption /// </summary> /// <param name = "StringS QL "> </param> // <returns> </returns> stringQueryStringEncodeCode (stringStringSQL ); /// <summary> /// QueryString decryption /// </summary> /// <param name = "StringSQL"> </param> /// <returns> </returns> stringQueryStringDncodeCode (stringStringSQL ); # endregion # region (2) rijndael algorithm // <summary> // encryption method // </summary> /// <param name = "Source"> string to be encrypted </param>/ // <returns> encrypted string </returns> stringRijndaelEncrypt (StringSource ); /// <summary> /// Decryption Method /// </summary> /// <param name = "Source"> string to be decrypted </param> /// <returns> decrypted string </returns> stringRijndaelDecrypt (stringSource ); # endregion (2) Rijndael algorithm # region (3) mix Base64 and UTF8 /// <summary> // string encryption /// </summary> /// <param name = "bb"> </param> /// <returns> </returns> stringBUEncrypt (string bb ); /// <summary> /// string decryption /// </summary> /// <param name = "aa"> </para M> // <returns> </returns> stringBUDecrypt (string aa); # endregion # region (4) fixed key algorithm // <summary> // string encryption // </summary> /// <param name = "strText"> </param> // <returns> </returns> stringSKeyEncrypt (string strText ); /// <summary> /// string decryption /// </summary> /// <param name = "strText"> </param> /// <returns> </returns> stringSKeyDecrypt (string strText ); # endregion # region (5) DES algorithm // <summary> /// DES encryption // </summary> /// <param name = "strSource"> </param> /// <returns> </returns> stringDESEncrypt (string strSource ); /// <summary> // DES decryption // </summary> /// <param name = "strSource"> </param> /// <returns> </returns> stringDESDecrypt (string strSource ); # endregion # region (6) encrypted password MD5T and SHA1 /// <summary> // encrypted password MD5T and SHA1 /// </summary> /// <param name = "strSource"> string </ param> // <param name = "str Flag "> encryption type </param> /// <param name =" substringlen "> encryption length </param> /// <returns> </returns> string encrypting (string strSource, int strFlag, int substringlen); # endregion} // <summary> // defines the method of the Interface Class Encryption Class /// </summary> publicclassStringEncryptionDecryption: interFaceStringEncryptionDecryption {# region (1) queryString encryption and decryption start /// <summary> // QueryString encryption /// </summary> /// <param name = "code"> </param> /// <Returns> </returns> publicstringQueryStringEncodeCode (string code) {string result = ""; if (code = null | code = "") {result = "";} else {result = Convert. toBase64String (System. text. encoding. default. getBytes ("" + code + "")). replace ("+", "% 2B");} return result ;} /// <summary> /// QueryString decryption /// </summary> /// <param name = "code"> </param> /// <returns> </returns> publicstringQueryStringDncodeCo De (string code) {string result = ""; if (code = null | code = "") {result = "";} else {try {result = System. text. encoding. default. getString (Convert. fromBase64String (code. replace ("% 2B", "+");} catch (FormatException ex) /// throw an exception [error message "invalid Base-64 character array length"] {result = "0" ;}} return result ;}# endregion (1) queryString encryption and decryption end # region (2) Rijndael algorithm privatestatic1_ricalgorithm mobjCryptoService = NewRijndaelManaged (); privatestaticstringKey = "Guz (% & hj7x89H $ yuBI0456FtmaT5 & fvHUFCy76 * h % (HilJ $ lhj! Y6 & (* jkP87jH7 "; /// <summary> /// obtain the key // </summary> /// <returns> key </returns> privatebyte [] GetLegalKey () {string sTemp = Key; mobjCryptoService. generateKey (); byte [] bytTemp = mobjCryptoService. key; intKeyLength = bytTemp. length; if (sTemp. length> KeyLength) sTemp = sTemp. substring (0, KeyLength); elseif (sTemp. length <KeyLength) sTemp = sTemp. padRight (KeyLength, ''); returnASCIIEncoding. ASCII. getBytes (STemp );} /// <summary> /// obtain the initial vector IV /// </summary> /// <returns> initial test vector IV </returns> privatebyte [] GetLegalIV () {string sTemp = "E4ghj * Ghg7! RNIfb & 95GUY86GfghUb # er57HBh (u % g6HJ ($ jhWk7 &! Hg4ui % $ hjk "; mobjCryptoService. generateIV (); byte [] bytTemp = mobjCryptoService. IV; intIVLength = bytTemp. length; if (sTemp. length> IVLength) sTemp = sTemp. substring (0, IVLength); elseif (sTemp. length <IVLength) sTemp = sTemp. padRight (IVLength, ''); returnASCIIEncoding. ASCII. getBytes (sTemp );} /// <summary> /// encryption method /// </summary> /// <param name = "Source"> string to be encrypted </param> /// <returns> encrypted string </returns> publi CstringRijndaelEncrypt (stringSource) {byte [] bytIn = UTF8Encoding. UTF8.GetBytes (Source); MemoryStream MS = newMemoryStream (); mobjCryptoService. key = GetLegalKey (); mobjCryptoService. IV = GetLegalIV (); ICryptoTransform encrypto = mobjCryptoService. createEncryptor (); CryptoStream cs = newCryptoStream (MS, encrypto, CryptoStreamMode. write); cs. write (bytIn, 0, bytIn. length); cs. flushFinalBlock (); ms. close (); Byte [] bytOut = ms. toArray (); returnConvert. toBase64String (bytOut );} /// <summary> /// Decryption Method /// </summary> /// <param name = "Source"> string to be decrypted </param> /// <returns> decrypted string </returns> publicstringRijndaelDecrypt (stringSource) {try {byte [] bytIn = Convert. fromBase64String (Source); MemoryStream MS = newMemoryStream (bytIn, 0, bytIn. length); mobjCryptoService. key = GetLegalKey (); mobjCryptoService. IV = GetLega LIV (); ICryptoTransform encrypto = mobjCryptoService. createDecryptor (); CryptoStream cs = newCryptoStream (MS, encrypto, CryptoStreamMode. read); StreamReader sr = newStreamReader (cs); return sr. readToEnd ();} catch (Exception ex) {return ex. message ;}# endregion # region (3) Mix Base64 and UTF8 // string encryption publicstringBUEncrypt (string bb) {byte [] by = newbyte [bb. length]; by = System. text. encoding. UTF8.GetBytes (bb ); String r = Convert. toBase64String (by); return r;} // string decryption publicstringBUDecrypt (string aa) {try {byte [] by = Convert. fromBase64String (aa); string r = Encoding. UTF8.GetString (by); return r;} catch (Exception ex) {return ex. message ;}# endregion # region (4) fixed key algorithm publicstaticByte [] Iv64 = {, 44,}; publicstaticByte [] byKey64 =, 50, 60, 70, 80}; // string encryption publicstringSKeyEnc Rypt (string strText) {try {DESCryptoServiceProvider des = newDESCryptoServiceProvider (); Byte [] inputByteArray = Encoding. UTF8.GetBytes (strText); MemoryStream MS = newMemoryStream (); CryptoStream cs = newCryptoStream (MS, des. createEncryptor (byKey64, Iv64), CryptoStreamMode. write); cs. write (inputByteArray, 0, inputByteArray. length); cs. flushFinalBlock (); returnConvert. toBase64String (ms. toArray ();} cat Ch (Exception ex) {return ex. message ;}// string decryption publicstringSKeyDecrypt (string strText) {Byte [] inputByteArray = newbyte [strText. length]; try {DESCryptoServiceProvider des = newDESCryptoServiceProvider (); inputByteArray = Convert. fromBase64String (strText); MemoryStream MS = newMemoryStream (); CryptoStream cs = newCryptoStream (MS, des. createDecryptor (byKey64, Iv64), CryptoStreamMode. write); cs. write (I NputByteArray, 0, inputByteArray. length); cs. flushFinalBlock (); System. text. encoding encoding = System. text. encoding. UTF8; return encoding. getString (ms. toArray ();} catch (Exception ex) {return ex. message ;}# endregion # region (5) DES algorithm publicstaticbyte [] region ey = newbyte [] {0x82, 0xBC, 0xA1, 0x6A, 0xF5, 0x87, 0x3B, 0xE6, 0x59, 0x6A, 0x32, 0x64, 0x7F, 0x3A, 0x2A, 0xBB, 0x2B, 0x68, 0xE2, 0x5F, 0x06, 0xFB, 0xB8, 0x2D, 0x67,0 XB3, 0x55, 0x19, 0x4E, 0xB8, 0xBF, 0xDD }; /// <summary> // DES encryption // </summary> /// <param name = "strSource"> string to be encrypted </param> // <param name = "key"> 32-bit Key value </param> // <returns> encrypted string </returns> publicstringDESEncrypt (string strSource) {returnDESEncryptF (strSource, cipher ey);} privatestringDESEncryptF (string strSource, byte [] key) {fig sa = Rijndael. create (); sa. key = key; sa. mode = CipherMode. EC B; sa. padding = PaddingMode. zeros; MemoryStream MS = newMemoryStream (); CryptoStream cs = newCryptoStream (MS, sa. createEncryptor (), CryptoStreamMode. write); byte [] byt = Encoding. unicode. getBytes (strSource); cs. write (byt, 0, byt. length); cs. flushFinalBlock (); cs. close (); returnConvert. toBase64String (ms. toArray ());} /// <summary> // DES decryption // </summary> /// <param name = "strSource"> string to be decrypted </param> /// <pa Ram name = "key"> 32-bit Key value </param> // <returns> decrypted string </returns> publicstringDESDecrypt (string strSource) {returnDESDecryptF (strSource, required ey);} privatestringDESDecryptF (string strSource, byte [] key) {try {fig sa = Rijndael. create (); sa. key = key; sa. mode = CipherMode. ECB; sa. padding = PaddingMode. zeros; ICryptoTransform ct = sa. createDecryptor (); byte [] byt = Convert. fromBase64String (strS Ource); MemoryStream MS = newMemoryStream (byt); CryptoStream cs = newCryptoStream (MS, ct, CryptoStreamMode. read); StreamReader sr = newStreamReader (cs, Encoding. unicode); return sr. readToEnd ();} catch (Exception ex) {return ex. message ;}# endregion # region (6) encrypted password MD5T and SHA1 /// <summary> // encrypted password MD5T and SHA1 /// </summary> /// <param name = "strSource"> string </ param> /// <param name = "strFlag"> encryption type </param> /// <Param name = "substringlen"> encryption length </param> /// <returns> </returns> // publicstring encrypting (string strSource, int strFlag, int substringlen) {string ss = ""; if (strFlag = 1) // MD5 encryption {if (substringlen = 16) // 16-bit MD5 encryption (9 ~ with 32-bit encryption ~ 25 characters) {ss = FormsAuthentication. hashPasswordForStoringInConfigFile (strSource, "MD5 "). toLower (). substring (8, 16);} elseif (substringlen = 32) // 32-bit encryption {ss = FormsAuthentication. hashPasswordForStoringInConfigFile (strSource, "MD5 "). toLower () ;}} elseif (strFlag = 2) // SHA1 encryption {if (substringlen = 16) // SHA1 16-bit encryption {ss = FormsAuthentication. hashPasswordForStoringInConfigFile (strSource, "SHA1 "). toLower (). substring (8, 16);} elseif (substringlen = 32) // SHA1 40-bit encryption {ss = FormsAuthentication. hashPasswordForStoringInConfigFile (strSource, "SHA1 "). toLower () ;}} else {ss = "" ;}return ss ;}# endregion }}