Java

Set the OAEP Hash Algorithm for Encrypted Email

Demonstrates the Chilkat Email.OaepHash property, which selects the hash algorithm used by OAEP padding when encrypting email with RSAES-OAEP. Valid values are sha1, sha256, sha384, and sha512; the default is sha256. This property is used only when OaepPadding is true, so this example enables OAEP first.

Background: OAEP ("Optimal Asymmetric Encryption Padding") uses a hash function internally as part of the randomized padding it wraps around the data before RSA encryption. The choice of hash affects security and, importantly, interoperability: the sender and recipient must use the same OAEP hash, or decryption fails. That is why this is exposed as an explicit setting rather than left implicit.

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Java

import com.chilkatsoft.*;

public class ChilkatExample {

  static {
    try {
        System.loadLibrary("chilkat");
    } catch (UnsatisfiedLinkError e) {
      System.err.println("Native code library failed to load.\n" + e);
      System.exit(1);
    }
  }

  public static void main(String argv[])
  {
    //  Demonstrates the Email.OaepHash property, which selects the hash algorithm used by
    //  OAEP padding when encrypting email with RSAES-OAEP.  Valid values: sha1, sha256,
    //  sha384, sha512.  The default is sha256.  It is used only when OaepPadding is true.

    CkEmail email = new CkEmail();
    email.put_Subject("Encrypted with RSAES-OAEP");

    //  OAEP padding must be enabled for the OAEP hash to take effect.
    email.put_OaepPadding(true);
    email.put_OaepHash("sha256");

    System.out.println("OaepHash = " + email.oaepHash());
  }
}