DataFlex

AES Encrypt and Decrypt a File

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

Use ChilkatAx-win32.pkg

Procedure Test
    Boolean iSuccess
    Handle hoCrypt
    String sIvHex
    String sKeyHex
    String sInFile
    String sOutFile
    Handle hoDecrypt
    String sTemp1

    Move False To iSuccess

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

    Get Create (RefClass(cComChilkatCrypt2)) To hoCrypt
    If (Not(IsComObjectCreated(hoCrypt))) Begin
        Send CreateComObject of hoCrypt
    End

    Set ComCryptAlgorithm Of hoCrypt To "aes"

    // CipherMode may be "ecb" or "cbc"
    Set ComCipherMode Of hoCrypt To "cbc"

    // KeyLength may be 128, 192, 256
    Set ComKeyLength Of hoCrypt To 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.
    Set ComPaddingScheme Of hoCrypt To 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.
    Move "000102030405060708090A0B0C0D0E0F" To sIvHex
    Send ComSetEncodedIV To hoCrypt sIvHex "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.
    Move "000102030405060708090A0B0C0D0E0F101112131415161718191A1B1C1D1E1F" To sKeyHex
    Send ComSetEncodedKey To hoCrypt sKeyHex "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.
    Move "/Users/chilkat/testData/pdf/sample.pdf" To sInFile
    Move "/Users/chilkat/testData/p7m/sample.pdf.aes" To sOutFile
    Get ComCkEncryptFile Of hoCrypt sInFile sOutFile To iSuccess
    If (iSuccess <> True) Begin
        Get ComLastErrorText Of hoCrypt To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // For demonstration purposes, a different instance of the object will be used
    // for decryption.
    Get Create (RefClass(cComChilkatCrypt2)) To hoDecrypt
    If (Not(IsComObjectCreated(hoDecrypt))) Begin
        Send CreateComObject of hoDecrypt
    End

    // All settings must match to be able to decrypt:
    Set ComCryptAlgorithm Of hoDecrypt To "aes"
    Set ComCipherMode Of hoDecrypt To "cbc"
    Set ComKeyLength Of hoDecrypt To 256
    Set ComPaddingScheme Of hoDecrypt To 0
    Send ComSetEncodedIV To hoDecrypt sIvHex "hex"
    Send ComSetEncodedKey To hoDecrypt sKeyHex "hex"

    // Decrypt the .aes
    Move "/Users/chilkat/testData/p7m/sample.pdf.aes" To sInFile
    Move "/Users/chilkat/testData/pdf/recovered.pdf" To sOutFile
    Get ComCkDecryptFile Of hoDecrypt sInFile sOutFile To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoDecrypt To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    Showln "Success!"


End_Procedure