Visual FoxPro Requires Chilkat v11.0.0+

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. Visual FoxPro

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

lnSuccess = 0

*  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.
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

loRsa = CreateObject('Chilkat.Rsa')

*  Tell RSA to use the public key.
loRsa.UsePublicKey(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.
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.UsePrivateKey(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