PureBasic

Get EC Public Key from EC Private Key

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

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

Procedure ChilkatExample()

    success.i = 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-----

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

    success = CkPrivateKey::ckLoadPemFile(privKey,"qa_data/ecc/secp256r1-key-pkcs8.pem")
    If success = 0
        Debug CkPrivateKey::ckLastErrorText(privKey)
        CkPrivateKey::ckDispose(privKey)
        ProcedureReturn
    EndIf

    ; Get the public key.
    pubKey.i = CkPublicKey::ckCreate()
    If pubKey.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    CkPrivateKey::ckToPublicKey(privKey,pubKey)

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

    Debug "Success."


    CkPrivateKey::ckDispose(privKey)
    CkPublicKey::ckDispose(pubKey)


    ProcedureReturn
EndProcedure