PureBasic

Ed25519ph Sign and Verify

See more Ed25519 Examples

Demonstrates how to create an Ed25519ph signature, and then to verify it.

Note: This example requires Chilkat v9.5.0.91 or greater.

PureBasic

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

Procedure ChilkatExample()

    success.i = 0

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

    ; Use the following test vector from https://www.rfc-editor.org/rfc/rfc8032#page-30

    ;    -----TEST abc
    ; 
    ;    ALGORITHM:
    ;    Ed25519ph
    ; 
    ;    SECRET KEY:
    ;    833fe62409237b9d62ec77587520911e
    ;    9a759cec1d19755b7da901b96dca3d42
    ; 
    ;    PUBLIC KEY:
    ;    ec172b93ad5e563bf4932c70e1245034
    ;    c35467ef2efd4d64ebf819683467e2bf
    ; 
    ;    MESSAGE (length 3 bytes):
    ;    616263
    ; 
    ;    SIGNATURE:
    ;    98a70222f0b8121aa9d30f813d683f80
    ;    9e462b469c7ff87639499bb94e6dae41
    ;    31f85042463c2a355a2003d062adf5aa
    ;    a10b8c61e636062aaad11c2a26083406

    privKeyHex.s = "833fe62409237b9d62ec77587520911e9a759cec1d19755b7da901b96dca3d42"
    pubKeyHex.s = "ec172b93ad5e563bf4932c70e1245034c35467ef2efd4d64ebf819683467e2bf"

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

    success = 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::ckAppendEncoded(bd,"616263","hex")

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

    ; Indicate we want the Ed25519ph instance.
    CkEdDSA::setCkAlgorithm(eddsa, "Ed25519ph")

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

    Debug "signature = " + hexSig

    ; The expected output is: 98a70222f0b8121aa9d30f813d683f80....

    ; 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 Ed25519ph signature is verified!"


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


    ProcedureReturn
EndProcedure