Node.js

Example: Hash Text in Chunks

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

NODEJS_PRELUDE

function chilkatExample() {

    var success = false;

    var crypt = new chilkat.Crypt2();
    crypt.HashAlgorithm = "sha256";
    crypt.Charset = "utf-8";

    var bd = new chilkat.BinData();

    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=

}

chilkatExample();