(PureBasic) Get an EC Key in Raw Hex Format

Demonstrates how to get the private and public key parts of an EC (ECDSA) key in lowercase hex formmat.

Note: This example requires Chilkat v9.5.0.83 or greater.

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IncludeFile "CkStringBuilder.pb"
IncludeFile "CkPrivateKey.pb"

Procedure ChilkatExample()

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

    ; Load an EC key from some format..
    privKey.i = CkPrivateKey::ckCreate()
    If privKey.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    ; This loads an ECDSA key from an unencrypted PEM file (no password required).
    success.i = CkPrivateKey::ckLoadAnyFormatFile(privKey,"qa_data/ecc/openssl_ecc_privKey.pem","")
    If success = 0
        Debug CkPrivateKey::ckLastErrorText(privKey)
        CkPrivateKey::ckDispose(privKey)
        ProcedureReturn
    EndIf

    ; The key type should be "ecc" to indicate an EC key.
    Debug "key type = " + CkPrivateKey::ckKeyType(privKey)

    ; What is the size of the private key in bits?
    Debug "size in bits = " + Str(CkPrivateKey::ckBitLength(privKey))

    ; Get the private and public EC key parts in raw hex format:
    sbPubKeyHex.i = CkStringBuilder::ckCreate()
    If sbPubKeyHex.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    privKeyHex.s = CkPrivateKey::ckGetRawHex(privKey,sbPubKeyHex)

    ; If the private key size in bits is 256, then we should have a 32-byte key (a 64 character hex string).
    Debug "private key = " + privKeyHex

    ; The public key is composed of the "x" and "y" parts, and is composed like this:  04||HEX(x)||HEX(y)
    Debug "public key = " + CkStringBuilder::ckGetAsString(sbPubKeyHex)

    ; Sample output:
    ; key type = ecc
    ; size in bits = 256
    ; private key = ced36f2ba3332be439f79143d69937fc52494cd38e45243c3ea05db183919f1b
    ; public key = 045b4edcd501831740895f5907feabb71587076a6314d9d5141f9f8c33a478b8ce08b8dfd2a091eb6355803d7e729876c790bc0b176f2015f3bb103813753f676a


    CkPrivateKey::ckDispose(privKey)
    CkStringBuilder::ckDispose(sbPubKeyHex)


    ProcedureReturn
EndProcedure