(PureBasic) Ed25519 Sign and Verify

Demonstrates how to create an Ed25519 signature, and then to verify it.

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

Chilkat PureBasic Module Download Chilkat PureBasic Module

IncludeFile "CkBinData.pb"
IncludeFile "CkEdDSA.pb"
IncludeFile "CkPrivateKey.pb"
IncludeFile "CkPublicKey.pb"

Procedure ChilkatExample()

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

    privKeyHex.s = "1498b5467a63dffa2dc9d9e069caf075d16fc33fdd4c3b01bfadae6433767d93"
    pubKeyHex.s = "b7a3c12dc0c8c748ab07525b701122b88bd78f600c76342d27f25e5f92444cde"

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

    ; This example shows only one way of loading an Ed25519 private key.
    ; Chilkat can load other formats (JWK, PEM, ASN.1 DER, etc.)  
    ; You may do so by calling LoadAnyFormat or LoadAnyFormatFile.
    success.i = CkPrivateKey::ckLoadEd25519(privKey,privKeyHex,pubKeyHex)
    If success = 0
        Debug CkPrivateKey::ckLastErrorText(privKey)
        CkPrivateKey::ckDispose(privKey)
        ProcedureReturn
    EndIf

    ; The data to be signed...
    bd.i = CkBinData::ckCreate()
    If bd.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    CkBinData::ckAppendString(bd,"Message for Ed25519 signing","utf-8")

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

    hexSig.s = CkEdDSA::ckSignBdENC(eddsa,bd,"hexlower",privKey)

    Debug "signature = " + hexSig

    ; The expected output is: 6dd355667fae4eb43c6e0ab92e870edb2de0a88cae12dbd8591507f584fe4912babff497f1b8edf9567d2483d54ddc6459bea7855281b7a246a609e3001a4e08

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

    success = CkPublicKey::ckLoadEd25519(pubKey,pubKeyHex)
    If success = 0
        Debug CkPublicKey::ckLastErrorText(pubKey)
        CkPrivateKey::ckDispose(privKey)
        CkBinData::ckDispose(bd)
        CkEdDSA::ckDispose(eddsa)
        CkPublicKey::ckDispose(pubKey)
        ProcedureReturn
    EndIf

    bVerified.i = CkEdDSA::ckVerifyBdENC(eddsa,bd,hexSig,"hexlower",pubKey)
    If bVerified = 0
        Debug CkEdDSA::ckLastErrorText(eddsa)
        Debug "Failed to verify the signature."
        CkPrivateKey::ckDispose(privKey)
        CkBinData::ckDispose(bd)
        CkEdDSA::ckDispose(eddsa)
        CkPublicKey::ckDispose(pubKey)
        ProcedureReturn
    EndIf

    Debug "The Ed25519 signature is verified!"


    CkPrivateKey::ckDispose(privKey)
    CkBinData::ckDispose(bd)
    CkEdDSA::ckDispose(eddsa)
    CkPublicKey::ckDispose(pubKey)


    ProcedureReturn
EndProcedure