PowerBuilder

AES Encrypt and Decrypt a File

_LANGUAGE_ demonstrates how to AES encrypt a file of any size, and then decrypt. PowerBuilder

integer li_rc
integer li_Success
oleobject loo_Crypt
string ls_IvHex
string ls_KeyHex
string ls_InFile
string ls_OutFile
oleobject loo_Decrypt

li_Success = 0

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

loo_Crypt = create oleobject
li_rc = loo_Crypt.ConnectToNewObject("Chilkat.Crypt2")
if li_rc < 0 then
    destroy loo_Crypt
    MessageBox("Error","Connecting to COM object failed")
    return
end if

loo_Crypt.CryptAlgorithm = "aes"

// CipherMode may be "ecb" or "cbc"
loo_Crypt.CipherMode = "cbc"

// KeyLength may be 128, 192, 256
loo_Crypt.KeyLength = 256

// The padding scheme determines the contents of the bytes
// that are added to pad the result to a multiple of the
// encryption algorithm's block size.  AES has a block
// size of 16 bytes, so encrypted output is always
// a multiple of 16.
loo_Crypt.PaddingScheme = 0

// An initialization vector is required if using CBC mode.
// ECB mode does not use an IV.
// The length of the IV is equal to the algorithm's block size.
// It is NOT equal to the length of the key.
ls_IvHex = "000102030405060708090A0B0C0D0E0F"
loo_Crypt.SetEncodedIV(ls_IvHex,"hex")

// The secret key must equal the size of the key.  For
// 256-bit encryption, the binary secret key is 32 bytes.
// For 128-bit encryption, the binary secret key is 16 bytes.
ls_KeyHex = "000102030405060708090A0B0C0D0E0F101112131415161718191A1B1C1D1E1F"
loo_Crypt.SetEncodedKey(ls_KeyHex,"hex")

// Encrypt a file, producing the .aes as output.
// The input file is unchanged, the output .aes contains the encrypted
// contents of the input file.

// Note: The .aes output file has no file format.  It is simply a stream
// of bytes that resembles random binary data.
ls_InFile = "/Users/chilkat/testData/pdf/sample.pdf"
ls_OutFile = "/Users/chilkat/testData/p7m/sample.pdf.aes"
li_Success = loo_Crypt.CkEncryptFile(ls_InFile,ls_OutFile)
if li_Success <> 1 then
    Write-Debug loo_Crypt.LastErrorText
    destroy loo_Crypt
    return
end if

// For demonstration purposes, a different instance of the object will be used
// for decryption.
loo_Decrypt = create oleobject
li_rc = loo_Decrypt.ConnectToNewObject("Chilkat.Crypt2")

// All settings must match to be able to decrypt:
loo_Decrypt.CryptAlgorithm = "aes"
loo_Decrypt.CipherMode = "cbc"
loo_Decrypt.KeyLength = 256
loo_Decrypt.PaddingScheme = 0
loo_Decrypt.SetEncodedIV(ls_IvHex,"hex")
loo_Decrypt.SetEncodedKey(ls_KeyHex,"hex")

// Decrypt the .aes
ls_InFile = "/Users/chilkat/testData/p7m/sample.pdf.aes"
ls_OutFile = "/Users/chilkat/testData/pdf/recovered.pdf"
li_Success = loo_Decrypt.CkDecryptFile(ls_InFile,ls_OutFile)
if li_Success = 0 then
    Write-Debug loo_Decrypt.LastErrorText
    destroy loo_Crypt
    destroy loo_Decrypt
    return
end if

Write-Debug "Success!"


destroy loo_Crypt
destroy loo_Decrypt