(JavaScript) Example: Hash Text in Chunks

Shows how to generate a final hash, like SHA-256, for a large text by processing it in chunks.

Note

This example is intended for running within a Chilkat.Js embedded JavaScript engine. All Chilkat JavaScript examples require Chilkat v11.4.0 or greater.

var success = false;

var crypt = new CkCrypt2();
crypt.HashAlgorithm = "sha256";
crypt.Charset = "utf-8";

var bd = new CkBinData();

var s = "The quick brown fox jumped over the lazy dog.\r\n";

// Accumulate the text in a StringBuilder.  We'll demonstrate hashing the text in chunks,
// and then also hashing the entire text at once to show the results are the same.

bd.AppendString(s,"utf-8");
success = crypt.HashBeginString(s);

var i = 0;
while (i < 200) {
    bd.AppendString(s,"utf-8");
    crypt.HashMoreString(s);
    i = i+1;
}

// Get the hash in base64 format.
crypt.EncodingMode = "base64";

var encodedHash = crypt.HashFinalENC();
console.log("Hash computed in chunks: " + encodedHash);

// Let's alternatively compute the hash of the entire amount of data at once,
// to show the hash computation is the same:
encodedHash = crypt.HashBdENC(bd);
console.log("Hash computed in 1 step: " + encodedHash);

// Output:

// Hash computed in chunks: unwkVff61k40roRIJizaknreScHaL6frWe37kydXbZQ=
// Hash computed in 1 step: unwkVff61k40roRIJizaknreScHaL6frWe37kydXbZQ=