Dart Requires Chilkat v11.0.0+

RSA Encrypt Hash using SHA256 hash function and SHA1 mask function

See more RSA Examples

How can this Javascript be duplicated using Chilkat?

function a(e, t) {
                var r = s.pki.publicKeyFromPem(e)
                  , n = r.encrypt(t, "RSA-OAEP", {
                    md: s.md.sha256.create(),
                    mgf1: {
                        md: s.md.sha1.create()
                    }
                });
                return s.util.encode64(n)
            }

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.

Dart

import 'package:chilkat/chilkat.dart';

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

  final pubkey = CkPublicKey();

  final sbPem = CkStringBuilder();
  final 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. 
  try {
    pubkey.loadFromString(sbPem.getAsString());
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  final originalData = 'This is the original data to be SHA-256 hashed and RSA encrypted.';

  // First we SHA-256 hash the original data to get the hash in base64 format:
  final crypt = CkCrypt2();
  crypt.hashAlgorithm = 'SHA-256';
  crypt.encodingMode = 'base64';
  final hashBase64 = crypt.hashStringENC(originalData);

  // Setup RSA to use OAEP padding with SHA-1 for the mask function.
  final rsa = CkRsa();
  rsa.pkcsPadding = false;
  rsa.oaepHash = 'SHA256';
  rsa.usePublicKey(pubkey);
  rsa.encodingMode = 'base64';

  // We can provide a binary encoding mode, such as "base64", "hex", "base64url", etc.
  // for the Charset property.   The Charset property was previously limited to character encodings, such as
  // "utf-8", "iso-8859-1", etc.  If a binary encoding is used, then the string passed in is decoded to the binary
  // bytes as indicated.  (If an actual charset, such as "utf-8" is used, then the input string is converted to the
  // byte representation of the charset, and then encrypted.)

  // Given that a hash is composed of non-text binary bytes, we'll set the Charset property equal to "base64" 
  // (because we have the base64 hash from above).
  rsa.charset = '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.
  final bUsePrivateKey = false;
  final String encryptedStr;
  try {
    encryptedStr = rsa.encryptStringENC(hashBase64, bUsePrivateKey);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  print('Base64 RSA encrypted output: $encryptedStr');
}