(PureBasic) RSA Encrypt and OpenSSL Decrypt

Demonstrates how to use Chilkat to RSA encrypt, and then use OpenSSL to decrypt.

Note: This example requires Chilkat v11.0.0 or greater.

Chilkat PureBasic Module Download Chilkat PureBasic Module

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

Procedure ChilkatExample()

    success.i = 0

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

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

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

    success = CkRsa::ckGenKey(rsa,2048,privKey)
    success = CkPrivateKey::ckSavePkcs8PemFile(privKey,"qa_output/privKey.pem")

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

    CkPrivateKey::ckToPublicKey(privKey,pubKey)

    CkRsa::setCkEncodingMode(rsa, "base64")
    plainText.s = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz01234567890"
    bUsePrivateKey.i = 0
    CkRsa::ckUsePublicKey(rsa,pubKey)
    encryptedStr.s = CkRsa::ckEncryptStringENC(rsa,plainText,bUsePrivateKey)

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

    CkBinData::ckAppendEncoded(bd,encryptedStr,"base64")
    success = CkBinData::ckWriteFile(bd,"qa_output/enc.dat")

    ; The OpenSSL command to decrypt is:
    ; openssl pkeyutl -in enc.dat -inkey privKey.pem -keyform PEM -pkeyopt rsa_padding_mode:pkcs1 -decrypt

    Debug "OK"


    CkRsa::ckDispose(rsa)
    CkPrivateKey::ckDispose(privKey)
    CkPublicKey::ckDispose(pubKey)
    CkBinData::ckDispose(bd)


    ProcedureReturn
EndProcedure