Xbase++ Requires Chilkat v11.0.0+

RSA Sign with PKCS8 Encrypted Key

See more RSA Examples

Demonstrates how to load a private key from an encrypted PKCS8 file and create an RSA digital signature (and then verify it). Xbase++

LOCAL nSuccess
LOCAL oPrivKey
LOCAL oRsa
LOCAL cStrData
LOCAL cHexSig
LOCAL oCert
LOCAL oPubKey
LOCAL oRsa2

nSuccess := 0

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

oPrivKey := CreateObject("Chilkat.PrivateKey")

//  Load the private key from an RSA PEM file:
nSuccess := oPrivKey:LoadAnyFormatFile("raul_privateKey.key", "a0123456789")
IF (nSuccess == 0)
    ? oPrivKey:LastErrorText
    oPrivKey:destroy()
    RETURN
ENDIF

oRsa := CreateObject("Chilkat.Rsa")

//  Import the private key into the RSA component:
nSuccess := oRsa:UsePrivateKey(oPrivKey)
IF (nSuccess == 0)
    ? oRsa:LastErrorText
    oPrivKey:destroy()
    oRsa:destroy()
    RETURN
ENDIF

//  This example will sign a string, and receive the signature
//  in a hex-encoded string.  Therefore, set the encoding mode
//  to "hex":
oRsa:EncodingMode := "hex"

cStrData := "This is the string to be signed."

//  Sign the string using the sha256 hash algorithm.
//  Other valid choices are sha1, sha384, sha512 and others.
cHexSig := oRsa:SignStringENC(cStrData, "sha256")
IF (oRsa:LastMethodSuccess == 0)
    ? oRsa:LastErrorText
    oPrivKey:destroy()
    oRsa:destroy()
    RETURN
ENDIF

? cHexSig

//  Now verify with the public key.
//  This example shows how to use the public key from 
//  a digital certificate (.cer file)
oCert := CreateObject("Chilkat.Cert")
nSuccess := oCert:LoadFromFile("raul_publicKey.cer")
IF (nSuccess == 0)
    ? oCert:LastErrorText
    oPrivKey:destroy()
    oRsa:destroy()
    oCert:destroy()
    RETURN
ENDIF

oPubKey := CreateObject("Chilkat.PublicKey")
oCert:GetPublicKey(oPubKey)

oRsa2 := CreateObject("Chilkat.Rsa")
nSuccess := oRsa2:UsePublicKey(oPubKey)
IF (nSuccess == 0)
    ? oRsa2:LastErrorText
    oPrivKey:destroy()
    oRsa:destroy()
    oCert:destroy()
    oPubKey:destroy()
    oRsa2:destroy()
    RETURN
ENDIF

//  Verify the signature against the original data:
oRsa2:EncodingMode := "hex"
nSuccess := oRsa2:VerifyStringENC(cStrData, "sha256", cHexSig)
IF (nSuccess == 0)
    ? oRsa2:LastErrorText
    oPrivKey:destroy()
    oRsa:destroy()
    oCert:destroy()
    oPubKey:destroy()
    oRsa2:destroy()
    RETURN
ENDIF

? "Signature verified!"

//  Verify with incorrect data:
nSuccess := oRsa2:VerifyStringENC("something else", "sha256", cHexSig)
IF (nSuccess != 1)
    ? "Signature not verified! (which was expected in this case)"
ELSE
    ? "Hmmm... that's not right..."
ENDIF

oPrivKey:destroy()
oRsa:destroy()
oCert:destroy()
oPubKey:destroy()
oRsa2:destroy()