Visual FoxPro

Demonstrate RSA Encrypt/Decrypt using BinData

See more RSA Examples

Demonstrates how to RSA encrypt and decrypt data contained in a Chilkat BinData object. Visual FoxPro

LOCAL lnSuccess
LOCAL loPubKey
LOCAL loRsa
LOCAL loBd
LOCAL i
LOCAL loPrivKey
LOCAL lcPassword

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("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

* Create some binary data to encrypt.
loBd = CreateObject('Chilkat.BinData')
i = 0
FOR i = 0 TO 49
    loBd.AppendByte(i)
NEXT

* Show the bytes to be encrypted in hex format:
? "To be encrypted: " + loBd.GetEncoded("hex")

* To be encrypted: 000102030405060708090A0B0C0D0E0F101112131415161718191A1B1C1D1E1F202122232425262728292A2B2C2D2E2F3031

* RSA encrypt the contents of the bd, replacing the contents with the RSA encrypted data.
loRsa.EncryptBd(loBd,0)

* Now it is encrypted.
? "Encrypted size = " + STR(loBd.NumBytes)
? loBd.GetEncoded("hex")

* Encrypted size = 256
* 749ED9D0A8767C06C09AD9697F654F86B145F966722F9714902C4175BDBD02E68984ECF111D4D461
* EDB4A8E677D399D19CCA60F35C6DE9972F4262880FE9D77DB75915393E8E7DB80AAB5E383013FAEB
* 60C77D1E6FECC9A7C8426976416C6218FE7DA998EE063CE709E79C240F8625F4A56A0A33AFD63F7A
* BA26F2A692B42E878C53B78602C725FE63FF961A46A2B9D436E5E3D9D64AE3F1D1F5AD5F5B47FCD69
* 447306B77F2FD6D766CCAA1A110A3371586B43DF0D7FFE2220D1B305CF9371AC342F849FB0C90CD99E
* C176928D877FE1C0DE1A7CB6EB824FEC7E1DCF90EF2C6BA9F1DFD3EBFBE89C51AF074DC6AE02E544A78
* 5018C36D3D48B2EF5202AF61AC

* ------------------------------------------------------------------------------------------------------------------------
* 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("rsaKeys/myTestRsaPrivate.pem",lcPassword)
IF (lnSuccess = 0) THEN
    ? loPrivKey.LastErrorText
    RELEASE loPubKey
    RELEASE loRsa
    RELEASE loBd
    RELEASE loPrivKey
    CANCEL
ENDIF

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

* Decrypt
lnSuccess = loRsa.DecryptBd(loBd,1)
IF (lnSuccess = 0) THEN
    ? loRsa.LastErrorText
    RELEASE loPubKey
    RELEASE loRsa
    RELEASE loBd
    RELEASE loPrivKey
    CANCEL
ENDIF

* Examine the contents of bd to see if it now contains the unencrypted original data.
? "Decrypted: " + loBd.GetEncoded("hex")

* Decrypted: 000102030405060708090A0B0C0D0E0F101112131415161718191A1B1C1D1E1F202122232425262728292A2B2C2D2E2F3031

RELEASE loPubKey
RELEASE loRsa
RELEASE loBd
RELEASE loPrivKey