(Visual FoxPro) RSA Encrypt String to Binary Result and Reverse

See more RSA Examples

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

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

LOCAL loPubKey
LOCAL lnSuccess
LOCAL loRsa
LOCAL loEncBytes
LOCAL loPrivKey
LOCAL lcPassword
LOCAL lcOriginalText

* 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.
* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.PublicKey')
loPubKey = CreateObject('Chilkat.PublicKey')
* In all Chilkat methods expecting a path, you pass either absolute or relative paths.
lnSuccess = loPubKey.LoadFromFile("qa_data/rsaKeys/myTestRsaPublic.pem")
IF (lnSuccess = 0) THEN
    ? loPubKey.LastErrorText
    RELEASE loPubKey
    CANCEL
ENDIF

* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.Rsa')
loRsa = CreateObject('Chilkat.Rsa')

* Tell RSA to use the public key.
loRsa.ImportPublicKeyObj(loPubKey)

* 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.
loRsa.Charset = "utf-8"

* Be Careful when Using non-us-ascii String Literals in Source Code

loEncBytes = loRsa.EncryptString("Élève français dîne à côté d’un café où l’on sert déjà du gâteau au chocolat et des éclairs délicieux",0)

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

* Load the matching 2048-bit RSA private key.
* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.PrivateKey')
loPrivKey = CreateObject('Chilkat.PrivateKey')
lcPassword = "secret"
lnSuccess = loPrivKey.LoadAnyFormatFile("qa_data/rsaKeys/myTestRsaPrivate.pem",lcPassword)
IF (lnSuccess = 0) THEN
    ? loPrivKey.LastErrorText
    RELEASE loPubKey
    RELEASE loRsa
    RELEASE loPrivKey
    CANCEL
ENDIF

* Tell the RSA object to use the private key.
loRsa.ImportPrivateKeyObj(loPrivKey)

* Indicate that after decrypting the resultant decrypted bytes contains the utf-8 byte representation of the text.
loRsa.Charset = "utf-8"
lcOriginalText = loRsa.DecryptString(loEncBytes,1)
IF (lnSuccess = 0) THEN
    ? loRsa.LastErrorText
    RELEASE loPubKey
    RELEASE loRsa
    RELEASE loPrivKey
    CANCEL
ENDIF

? "Original text = " + lcOriginalText
? "Success."

RELEASE loPubKey
RELEASE loRsa
RELEASE loPrivKey