(Excel) 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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' 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..
Dim privKey As Chilkat.PrivateKey
Set privKey = Chilkat.NewPrivateKey

' This loads an ECDSA key from an unencrypted PEM file (no password required).

success = privKey.LoadAnyFormatFile("qa_data/ecc/openssl_ecc_privKey.pem","")
If (success = False) Then
    Debug.Print privKey.LastErrorText
    Exit Sub
End If

' The key type should be "ecc" to indicate an EC key.
Debug.Print "key type = "; privKey.KeyType

' What is the size of the private key in bits?
Debug.Print "size in bits = "; privKey.BitLength

' Get the private and public EC key parts in raw hex format:
Dim sbPubKeyHex As Chilkat.StringBuilder
Set sbPubKeyHex = Chilkat.NewStringBuilder

privKeyHex = privKey.GetRawHex(sbPubKeyHex)

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

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