(Visual FoxPro) RSA Hash Binary Data and Sign (and Verify)

Demonstrates how to sign the hash of binary data. Also demonstrates how to verify the RSA signature.

Note: This example uses methods introduced in Chilkat v9.5.0.77.

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

LOCAL loPrivKey
LOCAL lnSuccess
LOCAL loRsa
LOCAL lcOriginalData
LOCAL loBdData
LOCAL loBdSignature
LOCAL loPubKey
LOCAL loRsa2
LOCAL lnBVerified

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

* Load an RSA private key for signing.
* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.PrivateKey')
loPrivKey = CreateObject('Chilkat.PrivateKey')
lnSuccess = loPrivKey.LoadEncryptedPemFile("qa_data/pem/rsa_passwd.pem","passwd")
IF (lnSuccess <> 1) THEN
    ? loPrivKey.LastErrorText
    RELEASE loPrivKey
    CANCEL
ENDIF

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

* We have some binary data (in hex) to sign
lcOriginalData = "0102030405060708090A"
* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.BinData')
loBdData = CreateObject('Chilkat.BinData')
loBdData.AppendEncoded(lcOriginalData,"hex")

* Hash (SHA-256) and sign the hash:
* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.BinData')
loBdSignature = CreateObject('Chilkat.BinData')
lnSuccess = loRsa.SignBd(loBdData,"sha256",loBdSignature)
IF (lnSuccess <> 1) THEN
    ? loRsa.LastErrorText
    RELEASE loPrivKey
    RELEASE loRsa
    RELEASE loBdData
    RELEASE loBdSignature
    CANCEL
ENDIF

* Show the RSA signature in base64
? loBdSignature.GetEncoded("base64")

* ------------------------------------------
* Get the public key from the private key
loPubKey = loPrivKey.GetPublicKey()

* Verify the signature..
* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.Rsa')
loRsa2 = CreateObject('Chilkat.Rsa')
loRsa2.ImportPublicKeyObj(loPubKey)

lnBVerified = loRsa2.VerifyBd(loBdData,"sha256",loBdSignature)
? "signature verified: " + STR(lnBVerified)

RELEASE loPubKey

RELEASE loPrivKey
RELEASE loRsa
RELEASE loBdData
RELEASE loBdSignature
RELEASE loRsa2