(Visual FoxPro) RSA SHA256 Signature using Private Key from Java Keystore

Signs plaintext using RSA SHA256 using a key from a Java keystore.

Duplicatest this code:

KeyStore keystore; // key repository for keys containing signature certificate
String alias; // alias for the certificate in the key repository
String password; // password for the certificate's private key
String plaintext; // text being signed


Signature signature = Signature.getInstance("SHA256withRSA");
signature.initSign((PrivateKey) keystore.getKey(alias, password.toCharArray()));
signature.update(plaintext.getBytes("UTF-8"));
byte[] rsa_text= signature.sign();

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

LOCAL loJks
LOCAL lcJksPassword
LOCAL lnSuccess
LOCAL lcPrivKeyPassword
LOCAL lnCaseSensitive
LOCAL loPrivKey
LOCAL loRsa
LOCAL loBinarySignature
LOCAL lcPlaintext
LOCAL lcSignatureStr

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

* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.JavaKeyStore')
loJks = CreateObject('Chilkat.JavaKeyStore')

lcJksPassword = "secret"

* Load the Java keystore from a file.  The JKS file password is used
* to verify the keyed digest that is found at the very end of the keystore.
* It verifies that the keystore has not been modified.
lnSuccess = loJks.LoadFile(lcJksPassword,"qa_data/jks/sample_secret.jks")
IF (lnSuccess <> 1) THEN
    ? loJks.LastErrorText
    RELEASE loJks
    CANCEL
ENDIF

* Get the private key from the JKS.
* The private key password may be different than the file password.
lcPrivKeyPassword = "secret"
lnCaseSensitive = 0
loPrivKey = loJks.FindPrivateKey(lcPrivKeyPassword,"some.alias",lnCaseSensitive)
IF (loJks.LastMethodSuccess <> 1) THEN
    ? loJks.LastErrorText
    RELEASE loJks
    CANCEL
ENDIF

* Establish the RSA object and tell it to use the private key..
* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.Rsa')
loRsa = CreateObject('Chilkat.Rsa')

lnSuccess = loRsa.ImportPrivateKeyObj(loPrivKey)
RELEASE loPrivKey
IF (lnSuccess <> 1) THEN
    ? loRsa.LastErrorText
    RELEASE loJks
    RELEASE loRsa
    CANCEL
ENDIF

* Indicate we'll be signing the utf-8 byte representation of the string..
loRsa.Charset = "utf-8"

* Sign some plaintext using RSA-SHA256

lcPlaintext = "this is the text to be signed"
loBinarySignature = loRsa.SignString(lcPlaintext,"SHA256")
IF (loRsa.LastMethodSuccess <> 1) THEN
    ? loRsa.LastErrorText
    RELEASE loJks
    RELEASE loRsa
    CANCEL
ENDIF

* Alternatively, if the signature is desired in some encoded string form,
* such as base64, base64-url, hex, etc.
loRsa.EncodingMode = "base64-url"
lcSignatureStr = loRsa.SignStringENC(lcPlaintext,"SHA256")
? "base64-url RSA signature: " + lcSignatureStr

RELEASE loJks
RELEASE loRsa