(Visual FoxPro) Generate ECDSA Key and Get Details as XML

Demonstrates how to generate an ECC key and gets the parts as XML.

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

LOCAL loEcc
LOCAL loFortuna
LOCAL lcEntropy
LOCAL lnSuccess
LOCAL loPrivKey
LOCAL loAsn
LOCAL loXml
LOCAL loCrypt
LOCAL lcPrivKeyHex

* 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.Ecc')
loEcc = CreateObject('Chilkat.Ecc')

* Generate a random ECC private key on the secp256k1 curve.
* Chilkat also supports other curves, such as secp384r1, secp521r1, and secp256r1.

* Create a Fortuna PRNG and seed it with system entropy.
* This will be our source of random data for generating the ECC private key.
* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.Prng')
loFortuna = CreateObject('Chilkat.Prng')
lcEntropy = loFortuna.GetEntropy(32,"base64")
lnSuccess = loFortuna.AddEntropy(lcEntropy,"base64")

loPrivKey = loEcc.GenEccKey("secp256k1",loFortuna)
IF (loEcc.LastMethodSuccess <> 1) THEN
    ? loEcc.LastErrorText
    RELEASE loEcc
    RELEASE loFortuna
    CANCEL
ENDIF

* An EC private key has this ASN.1
* ECPrivateKey ::= SEQUENCE {
*     version        INTEGER { ecPrivkeyVer1(1) } (ecPrivkeyVer1),
*     privateKey     OCTET STRING,
*     parameters [0] ECParameters {{ NamedCurve }} OPTIONAL,
*     publicKey  [1] BIT STRING OPTIONAL (This is the ANSI X9.63 public key format.)

* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.Asn')
loAsn = CreateObject('Chilkat.Asn')
lnSuccess = loAsn.LoadEncoded(loPrivKey.GetPkcs1ENC("base64"),"base64")
IF (lnSuccess <> 1) THEN
    ? loAsn.LastErrorText
    RELEASE loEcc
    RELEASE loFortuna
    RELEASE loAsn
    CANCEL
ENDIF

* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.Xml')
loXml = CreateObject('Chilkat.Xml')
loXml.LoadXml(loAsn.AsnToXml())

? loXml.GetXml()

* The XML looks like this:
* <?xml version="1.0" encoding="utf-8" ?>
* <sequence>
*     <int>01</int>
*     <octets>JgJvBG+3wletkJab8iXAkpz0O8/AgWZSpkYVcB7SpnU=</octets>
*     <contextSpecific tag="0" constructed="1">
*         <oid>1.3.132.0.10</oid>
*     </contextSpecific>
* </sequence>

* The 32-byte private key is in the octets..
* Get it as hex.
* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.Crypt2')
loCrypt = CreateObject('Chilkat.Crypt2')
lcPrivKeyHex = loCrypt.ReEncode(loXml.GetChildContent("octets"),"base64","hex")

? "EC private key as hex = " + lcPrivKeyHex

RELEASE loPrivKey

RELEASE loEcc
RELEASE loFortuna
RELEASE loAsn
RELEASE loXml
RELEASE loCrypt