Node.js

RSA-OAEP with SHA256 hashing

See more RSA Examples

RSA encrypt a SHA256 hash with OAEP padding. Node.js

NODEJS_PRELUDE

function chilkatExample() {

    var success = false;

    // This example requires the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    var pubkey = new chilkat.PublicKey();

    var sbPem = new chilkat.StringBuilder();
    var bCrlf = true;
    sbPem.AppendLine("-----BEGIN PUBLIC KEY-----",bCrlf);
    sbPem.AppendLine("MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEA33TqqLR3eeUmDtHS89qF",bCrlf);
    sbPem.AppendLine("3p4MP7Wfqt2Zjj3lZjLjjCGDvwr9cJNlNDiuKboODgUiT4ZdPWbOiMAfDcDzlOxA",bCrlf);
    sbPem.AppendLine("04DDnEFGAf+kDQiNSe2ZtqC7bnIc8+KSG/qOGQIVaay4Ucr6ovDkykO5Hxn7OU7s",bCrlf);
    sbPem.AppendLine("Jp9TP9H0JH8zMQA6YzijYH9LsupTerrY3U6zyihVEDXXOv08vBHk50BMFJbE9iwF",bCrlf);
    sbPem.AppendLine("wnxCsU5+UZUZYw87Uu0n4LPFS9BT8tUIvAfnRXIEWCha3KbFWmdZQZlyrFw0buUE",bCrlf);
    sbPem.AppendLine("f0YN3/Q0auBkdbDR/ES2PbgKTJdkjc/rEeM0TxvOUf7HuUNOhrtAVEN1D5uuxE1W",bCrlf);
    sbPem.AppendLine("SwIDAQAB",bCrlf);
    sbPem.AppendLine("-----END PUBLIC KEY-----",bCrlf);

    // Load the public key object from the PEM. 
    success = pubkey.LoadFromString(sbPem.GetAsString());
    if (success == false) {
        console.log(pubkey.LastErrorText);
        return;
    }

    // Build a small string to encrypt
    var json = new chilkat.JsonObject();
    json.UpdateString("example","123");
    json.UpdateString("hello","world");
    console.log(json.Emit());

    // This is the JSON to be RSA encrypted:  {"example":"123","hello":"world"}

    // IMPORTANT: RSA encryption is only used to encrypt small amounts of data.
    // RSA is only able to encrypt data to a maximum amount of your key size (2048 bits = 256 bytes) 
    // minus padding / header data (11 bytes for PKCS#1 v1.5 padding, 42 bytes for OAEP).
    // As a result it is often not possible to encrypt files with RSA directly. 
    // RSA is also not meant for this purpose. 
    // 
    // If you want to encrypt more data, you can use something like:
    // 1) Generate a 256-bit random keystring K
    // 2) Encrypt your data with AES-CBC with K
    // 3) Encrypt K with RSA
    // 4) Send both to the other side 

    var rsa = new chilkat.Rsa();
    rsa.PkcsPadding = false;
    rsa.OaepHash = "SHA-256";
    rsa.UsePublicKey(pubkey);
    rsa.EncodingMode = "base64";

    // Note: The OAEP padding uses random bytes in the padding, and therefore each time encryption happens,
    // even using the same data and key, the result will be different --  but still valid.  One should not expect
    // to get the same output.
    var bUsePrivateKey = false;
    var encryptedStr = rsa.EncryptStringENC(json.Emit(),bUsePrivateKey);
    if (rsa.LastMethodSuccess == false) {
        console.log(rsa.LastErrorText);
        return;
    }

    console.log("Result: " + encryptedStr);

}

chilkatExample();