PureBasic Requires Chilkat v11.0.0+

Encrypt with Chilkat, Decrypt with OpenSSL

See more OpenSSL Examples

Demonstrates how to RSA encrypt a string using Chilkat, and then shows the corresponding OpenSSL command to RSA decrypt. The OpenSSL command to decrypt is as follows:

openssl rsautl -decrypt -inkey VP_Private.pem -in rsa_encrypted.bin -out original.txt

PureBasic

IncludeFile "CkFileAccess.pb"
IncludeFile "CkPublicKey.pb"
IncludeFile "CkRsa.pb"

Procedure ChilkatExample()

    success.i = 0

    ;  This example 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

    ;  Note: RSA encryption uses the public key.  
    ;  RSA decryption uses the private key.
    ;  The reason is that the public key can be freely provided to anybody.  This allows anybody
    ;  to send an encrypted message to the private key owner, and only the private key owner 
    ;  can decrypt.
    key.i = CkPublicKey::ckCreate()
    If key.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    ;  Load an RSA public key from a PEM file:
    success = CkPublicKey::ckLoadFromFile(key,"qa_data/pem/VP_Public.pem")
    If success = 0
        Debug CkPublicKey::ckLastErrorText(key)
        CkRsa::ckDispose(rsa)
        CkPublicKey::ckDispose(key)
        ProcedureReturn
    EndIf

    ;  Load the public key into the RSA object.
    success = CkRsa::ckUsePublicKey(rsa,key)
    If success = 0
        Debug CkRsa::ckLastErrorText(rsa)
        CkRsa::ckDispose(rsa)
        CkPublicKey::ckDispose(key)
        ProcedureReturn
    EndIf

    strToEncrypt.s = "00000000;XYZ2-3BHQ-ABCD-MMVV;6MY1-GHJK-9LRR;0"

    ;  The LittleEndian property is 0 by default, but it is set here
    ;  anyway to show that LittleEndian byte ordering is required for OpenSSL compatibility.
    CkRsa::setCkLittleEndian(rsa, 0)

    usePrivateKey.i = 0
ERROR - PureBasic is an array language
    encryptedBytes = CkRsa::ckEncryptString(rsa,strToEncrypt,usePrivateKey)
    If CkRsa::ckLastMethodSuccess(rsa) = 0
        Debug CkRsa::ckLastErrorText(rsa)
        CkRsa::ckDispose(rsa)
        CkPublicKey::ckDispose(key)
        ProcedureReturn
    EndIf

    ;  The OpenSSL command to decrypt would be this:
    ;  openssl rsautl -decrypt -inkey VP_Private.pem -in rsa_encrypted.bin -out original.txt

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

    success = CkFileAccess::ckWriteEntireFile(fac,"qa_output/rsa_encrypted.bin",encryptedBytes)
    If success = 0
        Debug CkFileAccess::ckLastErrorText(fac)
        CkRsa::ckDispose(rsa)
        CkPublicKey::ckDispose(key)
        CkFileAccess::ckDispose(fac)
        ProcedureReturn
    EndIf

    Debug "RSA Encryption Succeeded."


    CkRsa::ckDispose(rsa)
    CkPublicKey::ckDispose(key)
    CkFileAccess::ckDispose(fac)


    ProcedureReturn
EndProcedure