(DataFlex) RSA Encrypt String to Encoded Result and Reverse

See more RSA Examples

Demonstrates how to RSA encrypt a string to a base64 encoded result, and the reverse.

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

Use ChilkatAx-win32.pkg

Procedure Test
    Variant vPubKey
    Handle hoPubKey
    Boolean iSuccess
    Handle hoRsa
    String sEncryptedB64
    Variant vPrivKey
    Handle hoPrivKey
    String sPassword
    String sOriginalText
    String sTemp1

    // The RSA public key is used for encryption, and the private key for decryption.

    // The public key's role is to make encryption accessible to anyone while ensuring that
    // only the private key holder can decrypt the messages.
    // The public key is designed to be widely distributed so anyone can use it to encrypt messages
    // intended for the owner of the private key.

    // Load our 2048-bit RSA public key.
    Get Create (RefClass(cComChilkatPublicKey)) To hoPubKey
    If (Not(IsComObjectCreated(hoPubKey))) Begin
        Send CreateComObject of hoPubKey
    End
    // In all Chilkat methods expecting a path, you pass either absolute or relative paths.
    Get ComLoadFromFile Of hoPubKey "rsaKeys/myTestRsaPublic.pem" To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoPubKey To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    Get Create (RefClass(cComChilkatRsa)) To hoRsa
    If (Not(IsComObjectCreated(hoRsa))) Begin
        Send CreateComObject of hoRsa
    End

    // Tell RSA to use the public key.
    Get pvComObject of hoPubKey to vPubKey
    Get ComImportPublicKeyObj Of hoRsa vPubKey To iSuccess

    // RSA encryption is for small amounts of data, on the order of 200 bytes or less.
    // The maximum number of bytes that can be RSA encrypted depends
    // on the RSA key size and padding scheme (OAEP padding vs PKCS#1 v1.5 padding).
    // For specific limits, see: RSA Encryption Maximum Number of Bytes

    // Encrypt the utf-8 byte representation of the string.
    Set ComCharset Of hoRsa To "utf-8"
    Set ComEncodingMode Of hoRsa To "base64"

    // Be Careful when Using non-us-ascii String Literals in Source Code
    Get ComEncryptStringENC Of hoRsa "Élève français dîne à côté d’un café où l’on sert déjà du gâteau au chocolat et des éclairs délicieux" False To sEncryptedB64

    // ------------------------------------------------------------------------------------------------------------------------
    // Let's decrypt, which requires the matching private key...

    // Load the matching 2048-bit RSA private key.
    Get Create (RefClass(cComChilkatPrivateKey)) To hoPrivKey
    If (Not(IsComObjectCreated(hoPrivKey))) Begin
        Send CreateComObject of hoPrivKey
    End
    Move "secret" To sPassword
    Get ComLoadAnyFormatFile Of hoPrivKey "rsaKeys/myTestRsaPrivate.pem" sPassword To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoPrivKey To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // Tell the RSA object to use the private key.
    Get pvComObject of hoPrivKey to vPrivKey
    Get ComImportPrivateKeyObj Of hoRsa vPrivKey To iSuccess

    // Indicate that after decrypting the resultant decrypted bytes contains the utf-8 byte representation of the text.
    Set ComCharset Of hoRsa To "utf-8"
    Set ComEncodingMode Of hoRsa To "base64"
    Get ComDecryptStringENC Of hoRsa sEncryptedB64 True To sOriginalText
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoRsa To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    Showln "Original text = " sOriginalText
    Showln "Success."


End_Procedure