c# - How to generate an md5 hash with a plaintext string and a known salt -

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• md5 hash salt keeping password in db in c# 4 answers

i have been going crazy trying figure out. there simple way in c# take string "password123" , salt "vfs5%s]m(_*y+tk" , generate single md5 hash. website http://free-online-web-tools.com/tool/md5 c#.

the below given function generates hash given plain text value , returns base64-encoded result. before hash computed, random salt generated , appended plain text. salt stored @ end of hash value, can used later hash verification.

plaintext value hashed. function not check whether parameter null.

name of hash algorithm. allowed values are: "md5", "sha1","sha256", "sha384", , "sha512" (if other value specified md5 hashing algorithm used). value case-insensitive.

in case set hashalgorithm "md5"

salt bytes. parameter can null, in case random salt value generated.

hash value formatted base64-encoded string.

public static string computehash(string   plaintext,                                  string   hashalgorithm,                                  byte[]   saltbytes) {     // if salt not specified, generate on fly.     if (saltbytes == null)     {         // define min , max salt sizes.         int minsaltsize = 4;         int maxsaltsize = 8;          // generate random number size of salt.         random  random = new random();         int saltsize = random.next(minsaltsize, maxsaltsize);          // allocate byte array, hold salt.         saltbytes = new byte[saltsize];          // initialize random number generator.         rngcryptoserviceprovider rng = new rngcryptoserviceprovider();          // fill salt cryptographically strong byte values.         rng.getnonzerobytes(saltbytes);      }      // convert plain text byte array.     byte[] plaintextbytes = encoding.utf8.getbytes(plaintext);      // allocate array, hold plain text , salt.     byte[] plaintextwithsaltbytes =              new byte[plaintextbytes.length + saltbytes.length];      // copy plain text bytes resulting array.     (int i=0; < plaintextbytes.length; i++)         plaintextwithsaltbytes[i] = plaintextbytes[i];      // append salt bytes resulting array.     (int i=0; < saltbytes.length; i++)         plaintextwithsaltbytes[plaintextbytes.length + i] = saltbytes[i];      // because support multiple hashing algorithms, must define     // hash object common (abstract) base class. specify     // actual hashing algorithm class later during object creation.     hashalgorithm hash;      // make sure hashing algorithm name specified.     if (hashalgorithm == null)         hashalgorithm = "";      // initialize appropriate hashing algorithm class.     switch (hashalgorithm.toupper())     {         case "sha1":             hash = new sha1managed();             break;          case "sha256":             hash = new sha256managed();             break;          case "sha384":             hash = new sha384managed();             break;          case "sha512":             hash = new sha512managed();             break;          default:             hash = new md5cryptoserviceprovider();             break;     }      // compute hash value of our plain text appended salt.     byte[] hashbytes = hash.computehash(plaintextwithsaltbytes);      // create array hold hash , original salt bytes.     byte[] hashwithsaltbytes = new byte[hashbytes.length +                                          saltbytes.length];      // copy hash bytes resulting array.     (int i=0; < hashbytes.length; i++)         hashwithsaltbytes[i] = hashbytes[i];      // append salt bytes result.     (int i=0; < saltbytes.length; i++)         hashwithsaltbytes[hashbytes.length + i] = saltbytes[i];      // convert result base64-encoded string.     string hashvalue = convert.tobase64string(hashwithsaltbytes);      // return result.     return hashvalue; } 

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