(PureBasic) Generate ECDSA Key and Get Details as XML

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

Chilkat PureBasic Module Download Chilkat PureBasic Module

IncludeFile "CkAsn.pb"
IncludeFile "CkEcc.pb"
IncludeFile "CkPrivateKey.pb"
IncludeFile "CkPrng.pb"
IncludeFile "CkXml.pb"
IncludeFile "CkCrypt2.pb"

Procedure ChilkatExample()

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

    ecc.i = CkEcc::ckCreate()
    If ecc.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    ;  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.
    fortuna.i = CkPrng::ckCreate()
    If fortuna.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    entropy.s = CkPrng::ckGetEntropy(fortuna,32,"base64")
    success.i = CkPrng::ckAddEntropy(fortuna,entropy,"base64")

    privKey.i = CkEcc::ckGenEccKey(ecc,"secp256k1",fortuna)
    If CkEcc::ckLastMethodSuccess(ecc) <> 1
        Debug CkEcc::ckLastErrorText(ecc)
        CkEcc::ckDispose(ecc)
        CkPrng::ckDispose(fortuna)
        ProcedureReturn
    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.)

    asn.i = CkAsn::ckCreate()
    If asn.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    success = CkAsn::ckLoadEncoded(asn,CkPrivateKey::ckGetPkcs1ENC(privKey,"base64"),"base64")
    If success <> 1
        Debug CkAsn::ckLastErrorText(asn)
        CkEcc::ckDispose(ecc)
        CkPrng::ckDispose(fortuna)
        CkAsn::ckDispose(asn)
        ProcedureReturn
    EndIf

    xml.i = CkXml::ckCreate()
    If xml.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    CkXml::ckLoadXml(xml,CkAsn::ckAsnToXml(asn))

    Debug CkXml::ckGetXml(xml)

    ;  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.
    crypt.i = CkCrypt2::ckCreate()
    If crypt.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    privKeyHex.s = CkCrypt2::ckReEncode(crypt,CkXml::ckGetChildContent(xml,"octets"),"base64","hex")

    Debug "EC private key as hex = " + privKeyHex

    CkPrivateKey::ckDispose(privKey)



    CkEcc::ckDispose(ecc)
    CkPrng::ckDispose(fortuna)
    CkAsn::ckDispose(asn)
    CkXml::ckDispose(xml)
    CkCrypt2::ckDispose(crypt)


    ProcedureReturn
EndProcedure