(PureBasic) RSA Decrypt using PEM

This example demonstrates decryping RSA encrypted data that is base64 encoded. It uses a private key loaded from a PEM file.

Chilkat PureBasic Module Download Chilkat PureBasic Module

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

Procedure ChilkatExample()

    ; This example assumes 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

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

    ; Load an RSA private key from an unencrypted PEM file:
    ; (To load from an encrypted PEM file, call LoadEncryptedPemFile instead.)

    success.i = CkPrivateKey::ckLoadPemFile(key,"qa_data/rsa/decryptTest/priv.pem")
    If success <> 1
        Debug CkPrivateKey::ckLastErrorText(key)
        CkRsa::ckDispose(rsa)
        CkPrivateKey::ckDispose(key)
        ProcedureReturn
    EndIf

    ; Make the key available to the RSA object
    success = CkRsa::ckImportPrivateKeyObj(rsa,key)
    If success <> 1
        Debug CkRsa::ckLastErrorText(rsa)
        CkRsa::ckDispose(rsa)
        CkPrivateKey::ckDispose(key)
        ProcedureReturn
    EndIf

    encryptedStr.s = "pP9XFJEsGgxPNHEgNiLB5H5ksCOXDk/G49BPTog1jKLAhYofV4UTH5k2TOYiqRnDnKs8+8uPoN/IxdiGXvuYG8HRzN0HtkhoZO/AxeyaB9S7eddCUlT0Pl2PEB2yQ9HG5rM7jqYOD6MAM4cuX7hqT8fa8tbzJzmBwdfFDBz94bwQjULHiO+gklIBC4vhkXT4yjuvEjxTAKU6tJeZYkBooJNdS/vE5RZRpuF6bGZU41Qc17qFR+iReBq+9f8IMmw8WR8fMbOCaygOfFS1nw7JVsIMGsAIXS8rUaJ/2DfGPfQx5HCiVtTOreGYRUI3esAQjnvUCnavZyQgs53nl7e2aA=="

    CkRsa::setCkEncodingMode(rsa, "base64")

    usePrivateKey.i = 1
    decryptedStr.s = CkRsa::ckDecryptStringENC(rsa,encryptedStr,usePrivateKey)

    Debug "Decrypted:"
    Debug decryptedStr


    CkRsa::ckDispose(rsa)
    CkPrivateKey::ckDispose(key)


    ProcedureReturn
EndProcedure