(PureBasic) RSASSA-PSS Algorithm with SHA256 Hashing

RSA encrypt a SHA256 hash with OAEP padding.

Chilkat PureBasic Module Download Chilkat PureBasic Module

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.

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

    ; Load the private key object from a PEM file.
    ; (To load from a PEM string, call LoadPem instead.)
    success.i = CkPrivateKey::ckLoadPemFile(privkey,"somePath/myPrivateKey.pem")
    If success <> 1
        Debug CkPrivateKey::ckLastErrorText(privkey)
        CkPrivateKey::ckDispose(privkey)
        ProcedureReturn
    EndIf

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

    ; Use RSA-PSS by setting OaepPadding = 1
    CkRsa::setCkOaepPadding(rsa, 1)
    ; Use SHA256
    CkRsa::setCkOaepHash(rsa, "SHA-256")

    CkRsa::ckImportPrivateKeyObj(rsa,privkey)

    ; Generate a base64 signature.
    CkRsa::setCkEncodingMode(rsa, "base64")

    sigStr.s = CkRsa::ckSignStringENC(rsa,"String to be signed","SHA-256")
    If CkRsa::ckLastMethodSuccess(rsa) <> 1
        Debug CkRsa::ckLastErrorText(rsa)
        CkPrivateKey::ckDispose(privkey)
        CkRsa::ckDispose(rsa)
        ProcedureReturn
    EndIf

    Debug "Signature: " + sigStr


    CkPrivateKey::ckDispose(privkey)
    CkRsa::ckDispose(rsa)


    ProcedureReturn
EndProcedure