(PureBasic) Duplicate openssl dgst -sha256 -sign private.pem -out sha256.sig in.dat

Demonstrates how to duplicate this OpenSSL command:

openssl dgst -sha256 -sign private.pem -out sha256.sig in.dat

1. Creates a SHA256 digest of the contents of the input file
2. Signs the SHA256 digest using the private key.

Chilkat PureBasic Module Download Chilkat PureBasic Module

IncludeFile "CkBinData.pb"
IncludeFile "CkPrivateKey.pb"
IncludeFile "CkRsa.pb"

Procedure ChilkatExample()

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

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

    ; Load the private key from an PEM file:
    success.i = CkPrivateKey::ckLoadPemFile(pkey,"private.pem")
    If success <> 1
        Debug CkPrivateKey::ckLastErrorText(pkey)
        CkPrivateKey::ckDispose(pkey)
        ProcedureReturn
    EndIf

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

    ; Import the private key into the RSA component:
    success = CkRsa::ckImportPrivateKeyObj(rsa,pkey)
    If success <> 1
        Debug CkRsa::ckLastErrorText(rsa)
        CkPrivateKey::ckDispose(pkey)
        CkRsa::ckDispose(rsa)
        ProcedureReturn
    EndIf

    ; OpenSSL uses big-endian.
    CkRsa::setCkLittleEndian(rsa, 0)

    ; Load the file to be signed.
    bdFileData.i = CkBinData::ckCreate()
    If bdFileData.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    success = CkBinData::ckLoadFile(bdFileData,"in.dat")

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

    success = CkRsa::ckSignBd(rsa,bdFileData,"sha256",bdSig)
    If success <> 1
        Debug CkRsa::ckLastErrorText(rsa)
        CkPrivateKey::ckDispose(pkey)
        CkRsa::ckDispose(rsa)
        CkBinData::ckDispose(bdFileData)
        CkBinData::ckDispose(bdSig)
        ProcedureReturn
    EndIf

    ; Save the binary signature to a file.
    success = CkBinData::ckWriteFile(bdSig,"signature.sig")
    If success <> 1
        Debug "Failed to write signature.sig."
        CkPrivateKey::ckDispose(pkey)
        CkRsa::ckDispose(rsa)
        CkBinData::ckDispose(bdFileData)
        CkBinData::ckDispose(bdSig)
        ProcedureReturn
    EndIf

    Debug "Success."


    CkPrivateKey::ckDispose(pkey)
    CkRsa::ckDispose(rsa)
    CkBinData::ckDispose(bdFileData)
    CkBinData::ckDispose(bdSig)


    ProcedureReturn
EndProcedure