(Visual FoxPro) RSA Encrypt RSA/ECB/OAEPWithSHA1AndMGF1Padding

Demonstrates how to RSA encrypt using RSA/ECB/OAEPWithSHA1AndMGF1Padding. Also demonstrates RSA/ECB/OAEPWithSHA-256AndMGF1Padding. Both of these terms are from Java's JCE. Note: In this context, "ECB" doesn't actually mean anything. It's a symmetric cipher mode that doesn't apply (or make sense) in this context.

Note: This example requires Chilkat v11.0.0 or greater.

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

LOCAL lnSuccess
LOCAL loRsa
LOCAL loPubkey
LOCAL lcPlainText
LOCAL lnUsePrivateKey
LOCAL lcEncryptedStr
LOCAL loRsa2
LOCAL loPrivKey
LOCAL lcOriginalStr

lnSuccess = 0

* This example assumes the Chilkat API to have been previously unlocked.
* See Global Unlock Sample for sample code.

loRsa = CreateObject('Chilkat.Rsa')

* First load a public key object with a public key.
* In this case, we'll load it from a file.
loPubkey = CreateObject('Chilkat.PublicKey')
lnSuccess = loPubkey.LoadFromFile("qa_data/pem/rsa_public.pem")
IF (lnSuccess = 0) THEN
    ? loPubkey.LastErrorText
    RELEASE loRsa
    RELEASE loPubkey
    CANCEL
ENDIF

* RSA encryption is limited to small amounts of data. The limit
* is typically a few hundred bytes and is based on the key size and
* padding (OAEP vs. PKCS1_5).  RSA encryption is typically used for
* encrypting hashes or symmetric (bulk encryption algorithm) secret keys.
lcPlainText = "Time is an illusion. Lunchtime doubly so."

* Import the public key to be used for encrypting.
lnSuccess = loRsa.UsePublicKey(loPubkey)

* To get OAEP padding, set the PkcsPadding property equal to 0
loRsa.PkcsPadding = 0
loRsa.OaepHash = "sha256"

* Indicate we'll want hex output
loRsa.EncodingMode = "hex"

* Encrypt..
lnUsePrivateKey = 0
lcEncryptedStr = loRsa.EncryptStringENC(lcPlainText,lnUsePrivateKey)
? lcEncryptedStr

* -------------------------------------------------
* Now decrypt with the matching private key.
loRsa2 = CreateObject('Chilkat.Rsa')

loPrivKey = CreateObject('Chilkat.PrivateKey')
lnSuccess = loPrivKey.LoadEncryptedPem("qa_data/pem/rsa_passwd.pem","passwd")
IF (lnSuccess = 0) THEN
    ? loPrivKey.LastErrorText
    RELEASE loRsa
    RELEASE loPubkey
    RELEASE loRsa2
    RELEASE loPrivKey
    CANCEL
ENDIF

lnSuccess = loRsa2.UsePrivateKey(loPrivKey)

* Make sure we have the same settings used for encryption.
loRsa2.PkcsPadding = 0
loRsa2.EncodingMode = "hex"
loRsa2.OaepHash = "sha256"

lcOriginalStr = loRsa2.DecryptStringENC(lcEncryptedStr,1)

? lcOriginalStr

RELEASE loRsa
RELEASE loPubkey
RELEASE loRsa2
RELEASE loPrivKey