(Visual Basic 6.0) Get EC Public Key from EC Private Key

Demonstrates how to get an EC public key from an EC private key.

Note: This example requires Chilkat v11.0.0 or greater.

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

Dim success As Long
success = 0

' We have an ECC private key...
' The contents of the private key PEM file look like this:

' 	-----BEGIN PRIVATE KEY-----
' 	MIGHAgEAMBMGByqGSM49AgEGCCqGSM49AwEHBG0wawIBAQQg3J8q/24D1sEKGdP9
' 	72MGYElLGpw/a56Y3t6pfON3uhShRANCAATlSmoizyhAwoYZAOuFBATl07/1RR54
' 	a1Dzfm16grxJe666AGKR+bSs24hk7TEpaeCTvT8YOOM3l+xKFg7zq6Q9
' 	-----END PRIVATE KEY-----

Dim privKey As New PrivateKey
success = privKey.LoadPemFile("qa_data/ecc/secp256r1-key-pkcs8.pem")
If (success = 0) Then
    Debug.Print privKey.LastErrorText
    Exit Sub
End If

' Get the public key.
Dim pubKey As New PublicKey
success = privKey.ToPublicKey(pubKey)

' Save the public key to a PEM file.
success = pubKey.SavePemFile(0,"qa_data/ecc/secp256r1-pubkey.pem")
If (success = 0) Then
    Debug.Print pubKey.LastErrorText
    Exit Sub
End If

' The contents of the ECC public key PEM file look like this:

' 	-----BEGIN PUBLIC KEY-----
' 	MIIBSzCCAQMGByqGSM49AgEwgfcCAQEwLAYHKoZIzj0BAQIhAP////8AAAABAAAA
' 	AAAAAAAAAAAA////////////////MFsEIP////8AAAABAAAAAAAAAAAAAAAA////
' 	///////////8BCBaxjXYqjqT57PrvVV2mIa8ZR0GsMxTsPY7zjw+J9JgSwMVAMSd
' 	NgiG5wSTamZ44ROdJreBn36QBEEEaxfR8uEsQkf4vOblY6RA8ncDfYEt6zOg9KE5
' 	RdiYwpZP40Li/hp/m47n60p8D54WK84zV2sxXs7LtkBoN79R9QIhAP////8AAAAA
' 	//////////+85vqtpxeehPO5ysL8YyVRAgEBA0IABOVKaiLPKEDChhkA64UEBOXT
' 	v/VFHnhrUPN+bXqCvEl7rroAYpH5tKzbiGTtMSlp4JO9Pxg44zeX7EoWDvOrpD0=
' 	-----END PUBLIC KEY-----

Debug.Print "Success."