Visual FoxPro

Duplicate openssl dgst -sha256 -verify pubKey.pem -signature signature.sig in.dat

See more OpenSSL Examples

Demonstrates how to duplicate this OpenSSL command:

openssl dgst -sha256 -verify pubKey.pem -signature signature.sig in.dat

The in.dat file contains the original data that was signed, and can contain text or binary data of any type. The above OpenSSL command does the following:

1. Creates a SHA256 digest of the contents of the input file.
2. Verifies the SHA256 digest using the public key.

Visual FoxPro

LOCAL lnSuccess
LOCAL loPubKey
LOCAL loBdFileData
LOCAL loBdSig
LOCAL loRsa

lnSuccess = 0

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

loPubKey = CreateObject('Chilkat.PublicKey')

* Load the public key from an PEM file:
lnSuccess = loPubKey.LoadFromFile("pubKey.pem")
IF (lnSuccess = 0) THEN
    ? loPubKey.LastErrorText
    RELEASE loPubKey
    CANCEL
ENDIF

* Load the data of the original file that was signed.
loBdFileData = CreateObject('Chilkat.BinData')
lnSuccess = loBdFileData.LoadFile("in.dat")

* Load the signature.
loBdSig = CreateObject('Chilkat.BinData')
lnSuccess = loBdSig.LoadFile("signature.sig")

loRsa = CreateObject('Chilkat.Rsa')

* Import the public key into the RSA component:
lnSuccess = loRsa.UsePublicKey(loPubKey)
IF (lnSuccess = 0) THEN
    ? loRsa.LastErrorText
    RELEASE loPubKey
    RELEASE loBdFileData
    RELEASE loBdSig
    RELEASE loRsa
    CANCEL
ENDIF

* OpenSSL uses big-endian.
loRsa.LittleEndian = 0

lnSuccess = loRsa.VerifyBd(loBdFileData,"sha256",loBdSig)
IF (lnSuccess <> 1) THEN
    ? loRsa.LastErrorText
    ? "The signature was invalid."
    RELEASE loPubKey
    RELEASE loBdFileData
    RELEASE loBdSig
    RELEASE loRsa
    CANCEL
ENDIF

? "The signature was verified."

RELEASE loPubKey
RELEASE loBdFileData
RELEASE loBdSig
RELEASE loRsa