(PureBasic) RSA Encrypt Hash using SHA256 hash function and SHA1 mask function

Note: This example requires a feature introduced in Chilkat v9.5.0.66

How can this Javascript be duplicated using Chilkat?

function a(e, t) {
                var r = s.pki.publicKeyFromPem(e)
                  , n = r.encrypt(t, "RSA-OAEP", {
                    md: s.md.sha256.create(),
                    mgf1: {
                        md: s.md.sha1.create()
                    }
                });
                return s.util.encode64(n)
            }

Note: The OAEP padding uses random bytes in the padding, and therefore each time encryption happens, even using the same data and key, the result will be different -- but still valid. One should not expect to get the same output.

Chilkat PureBasic Module Download Chilkat PureBasic Module

IncludeFile "CkStringBuilder.pb"
IncludeFile "CkRsa.pb"
IncludeFile "CkPublicKey.pb"
IncludeFile "CkCrypt2.pb"

Procedure ChilkatExample()

    ; Note: This example requires a feature introduced in Chilkat v9.5.0.66

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

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

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

    bCrlf.i = 1
    CkStringBuilder::ckAppendLine(sbPem,"-----BEGIN PUBLIC KEY-----",bCrlf)
    CkStringBuilder::ckAppendLine(sbPem,"MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEA33TqqLR3eeUmDtHS89qF",bCrlf)
    CkStringBuilder::ckAppendLine(sbPem,"3p4MP7Wfqt2Zjj3lZjLjjCGDvwr9cJNlNDiuKboODgUiT4ZdPWbOiMAfDcDzlOxA",bCrlf)
    CkStringBuilder::ckAppendLine(sbPem,"04DDnEFGAf+kDQiNSe2ZtqC7bnIc8+KSG/qOGQIVaay4Ucr6ovDkykO5Hxn7OU7s",bCrlf)
    CkStringBuilder::ckAppendLine(sbPem,"Jp9TP9H0JH8zMQA6YzijYH9LsupTerrY3U6zyihVEDXXOv08vBHk50BMFJbE9iwF",bCrlf)
    CkStringBuilder::ckAppendLine(sbPem,"wnxCsU5+UZUZYw87Uu0n4LPFS9BT8tUIvAfnRXIEWCha3KbFWmdZQZlyrFw0buUE",bCrlf)
    CkStringBuilder::ckAppendLine(sbPem,"f0YN3/Q0auBkdbDR/ES2PbgKTJdkjc/rEeM0TxvOUf7HuUNOhrtAVEN1D5uuxE1W",bCrlf)
    CkStringBuilder::ckAppendLine(sbPem,"SwIDAQAB",bCrlf)
    CkStringBuilder::ckAppendLine(sbPem,"-----END PUBLIC KEY-----",bCrlf)

    ; Load the public key object from the PEM. 
    success.i = CkPublicKey::ckLoadFromString(pubkey,CkStringBuilder::ckGetAsString(sbPem))
    If success <> 1
        Debug CkPublicKey::ckLastErrorText(pubkey)
        CkPublicKey::ckDispose(pubkey)
        CkStringBuilder::ckDispose(sbPem)
        ProcedureReturn
    EndIf

    originalData.s = "This is the original data to be SHA-256 hashed and RSA encrypted."

    ; First we SHA-256 hash the original data to get the hash in base64 format:
    crypt.i = CkCrypt2::ckCreate()
    If crypt.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    CkCrypt2::setCkHashAlgorithm(crypt, "SHA-256")
    CkCrypt2::setCkEncodingMode(crypt, "base64")
    hashBase64.s = CkCrypt2::ckHashStringENC(crypt,originalData)

    ; Setup RSA to use OAEP padding with SHA-1 for the mask function.
    rsa.i = CkRsa::ckCreate()
    If rsa.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    CkRsa::setCkOaepPadding(rsa, 1)
    CkRsa::setCkOaepHash(rsa, "SHA1")
    CkRsa::ckImportPublicKeyObj(rsa,pubkey)
    CkRsa::setCkEncodingMode(rsa, "base64")

    ; Starting in v9.5.0.66, we can provide a binary encoding mode, such as "base64", "hex", "base64url", etc.
    ; for the Charset property.   The Charset property was previously limited to character encodings, such as
    ; "utf-8", "iso-8859-1", etc.  If a binary encoding is used, then the string passed in is decoded to the binary
    ; bytes as indicated.  (If an actual charset, such as "utf-8" is used, then the input string is converted to the
    ; byte representation of the charset, and then encrypted.)

    ; Given that a hash is composed of non-text binary bytes, we'll set the Charset property equal to "base64" 
    ; (because we have the base64 hash from above).
    CkRsa::setCkCharset(rsa, "base64")

    ; Note: The OAEP padding uses random bytes in the padding, and therefore each time encryption happens,
    ; even using the same data and key, the result will be different --  but still valid.  One should not expect
    ; to get the same output.
    bUsePrivateKey.i = 0
    encryptedStr.s = CkRsa::ckEncryptStringENC(rsa,hashBase64,bUsePrivateKey)
    If CkRsa::ckLastMethodSuccess(rsa) <> 1
        Debug CkRsa::ckLastErrorText(rsa)
        CkPublicKey::ckDispose(pubkey)
        CkStringBuilder::ckDispose(sbPem)
        CkCrypt2::ckDispose(crypt)
        CkRsa::ckDispose(rsa)
        ProcedureReturn
    EndIf

    Debug "Base64 RSA encrypted output: " + encryptedStr


    CkPublicKey::ckDispose(pubkey)
    CkStringBuilder::ckDispose(sbPem)
    CkCrypt2::ckDispose(crypt)
    CkRsa::ckDispose(rsa)


    ProcedureReturn
EndProcedure