(Lianja) Generate ECDSA Key and Get Details as XML

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

Chilkat Lianja Extension Download Chilkat Lianja Extension

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

loEcc = createobject("CkEcc")

//  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.
loFortuna = createobject("CkPrng")
lcEntropy = loFortuna.GetEntropy(32,"base64")
llSuccess = loFortuna.AddEntropy(lcEntropy,"base64")

loPrivKey = loEcc.GenEccKey("secp256k1",loFortuna)
if (loEcc.LastMethodSuccess <> .T.) then
    ? loEcc.LastErrorText
    release loEcc
    release loFortuna
    return
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.)

loAsn = createobject("CkAsn")
llSuccess = loAsn.LoadEncoded(loPrivKey.GetPkcs1ENC("base64"),"base64")
if (llSuccess <> .T.) then
    ? loAsn.LastErrorText
    release loEcc
    release loFortuna
    release loAsn
    return
endif

loXml = createobject("CkXml")
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.
loCrypt = createobject("CkCrypt2")
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