(PureBasic) Get ECC Public Key from ECC Private Key

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

Chilkat PureBasic Module Download Chilkat PureBasic Module

IncludeFile "CkPublicKey.pb"
IncludeFile "CkPrivateKey.pb"

Procedure ChilkatExample()

    ; 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-----

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

    success.i = CkPrivateKey::ckLoadPemFile(privKey,"qa_data/ecc/secp256r1-key-pkcs8.pem")
    If success <> 1
        Debug CkPrivateKey::ckLastErrorText(privKey)
        CkPrivateKey::ckDispose(privKey)
        ProcedureReturn
    EndIf

    ; Get the public key.
    pubKey.i = CkPrivateKey::ckGetPublicKey(privKey)
    If CkPrivateKey::ckLastMethodSuccess(privKey) <> 1
        Debug CkPrivateKey::ckLastErrorText(privKey)
        CkPrivateKey::ckDispose(privKey)
        ProcedureReturn
    EndIf

    ; Save the public key to a PEM file.
    success = CkPublicKey::ckSavePemFile(pubKey,0,"qa_data/ecc/secp256r1-pubkey.pem")
    If success <> 1
        Debug CkPublicKey::ckLastErrorText(pubKey)
        CkPublicKey::ckDispose(pubKey)

        CkPrivateKey::ckDispose(privKey)
        ProcedureReturn
    EndIf

    ; 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-----

    CkPublicKey::ckDispose(pubKey)

    Debug "Success."


    CkPrivateKey::ckDispose(privKey)


    ProcedureReturn
EndProcedure