.NET Identity 2.0 with custom salted passwords -

i'm trying switch .net identity old custom membership provider in existing mvc application, , maintain dapper orm, not entityframework comes out of box.

i'm stuck @ trying implement own ipasswordhasher, need existing credentials work. in hashpassword want return sha-computed hash of cleartext input combined user-specific salt, method receives clear text value, , no reference user login attempted.

where can salt? or going @ in wrong way?

i had pretty same thing migration. , recommended migration article provides solution problem.

you need merge old password hash salt 1 password field, separated special symbol (in article |, can choose own separator).

and passwordhasher should check password special symbol, , if present separate salt password , apply hashing.

here code snippet linked above article, though i've removed noise checking of plain-text password storage. presumes hash stored in format sh1hash|salt

public class sqlpasswordhasher : passwordhasher {     public override string hashpassword(string password)     {         return base.hashpassword(password);     }      public override passwordverificationresult verifyhashedpassword(string  hashedpassword, string providedpassword)     {         string[] passwordproperties = hashedpassword.split('|');         if (passwordproperties.length != 2)         {             // use default identity implementation             return base.verifyhashedpassword(hashedpassword, providedpassword);         }         else         {             string passwordhash = passwordproperties[0];             string salt = passwordproperties[1];             if (string.equals(encryptpassword(providedpassword, salt), passwordhash, stringcomparison.currentcultureignorecase))             {                 return passwordverificationresult.successrehashneeded;             }             else             {                 return passwordverificationresult.failed;             }         }     }      //this copied existing sql provider     private string encryptpassword(string pass, string salt)     {         byte[] bin = encoding.unicode.getbytes(pass);         byte[] bsalt = convert.frombase64string(salt);         byte[] bret = null;          hashalgorithm hm = hashalgorithm.create("sha1");         if (hm keyedhashalgorithm)         {             keyedhashalgorithm kha = (keyedhashalgorithm)hm;             if (kha.key.length == bsalt.length)             {                 kha.key = bsalt;             }             else if (kha.key.length < bsalt.length)             {                 byte[] bkey = new byte[kha.key.length];                 buffer.blockcopy(bsalt, 0, bkey, 0, bkey.length);                 kha.key = bkey;             }             else             {                 byte[] bkey = new byte[kha.key.length];                 (int iter = 0; iter < bkey.length; )                 {                     int len = math.min(bsalt.length, bkey.length - iter);                     buffer.blockcopy(bsalt, 0, bkey, iter, len);                     iter += len;                 }                 kha.key = bkey;             }             bret = kha.computehash(bin);         }         else         {             byte[] ball = new byte[bsalt.length + bin.length];             buffer.blockcopy(bsalt, 0, ball, 0, bsalt.length);             buffer.blockcopy(bin, 0, ball, bsalt.length, bin.length);             bret = hm.computehash(ball);         }          return convert.tobase64string(bret);     } }