DataFlex

AES and CHACHA20 Encrypt/Decrypt Text

See more Encryption Examples

Demonstrates the use of the new EncryptSb and DecryptSb methods introduced in Chilkat v9.5.0.67 to encrypt/decrypt the contents of StringBuilder objects.

Note: This example requires Chilkat v9.5.0.67 or greater.

DataFlex

Use ChilkatAx-win32.pkg

Procedure Test
    Boolean iSuccess
    Variant vSb
    Handle hoSb
    Integer i
    Handle hoCrypt
    String sIvHex
    String sKeyHex
    Variant vBdEncrypted
    Handle hoBdEncrypted
    Variant vSbOriginal
    Handle hoSbOriginal
    String sTemp1

    Move False To iSuccess

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

    // First build a string to be encrypted
    Get Create (RefClass(cComChilkatStringBuilder)) To hoSb
    If (Not(IsComObjectCreated(hoSb))) Begin
        Send CreateComObject of hoSb
    End
    Move 1 To i
    While (i < 10)
        Get ComAppendInt Of hoSb i To iSuccess
        Get ComAppend Of hoSb " the quick brown fox jumped over the lazy dog." + (character(13)) + (character(10)) To iSuccess
        Move (i + 1) To i
    Loop

    Get ComGetAsString Of hoSb To sTemp1
    Showln sTemp1

    // The string to be encrypted looks like this:

    // 1 the quick brown fox jumped over the lazy dog.
    // 2 the quick brown fox jumped over the lazy dog.
    // 3 the quick brown fox jumped over the lazy dog.
    // 4 the quick brown fox jumped over the lazy dog.
    // 5 the quick brown fox jumped over the lazy dog.
    // 6 the quick brown fox jumped over the lazy dog.
    // ...

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

    // Specify the encryption to be used.
    // First we'll do AES-128 CBC
    Set ComCryptAlgorithm Of hoCrypt To "aes"
    Set ComCipherMode Of hoCrypt To "cbc"
    Set ComKeyLength Of hoCrypt To 128

    Move "000102030405060708090A0B0C0D0E0F" To sIvHex
    Send ComSetEncodedIV To hoCrypt sIvHex "hex"

    Move "000102030405060708090A0B0C0D0E0F101112131415161718191A1B1C1D1E1F" To sKeyHex
    Send ComSetEncodedKey To hoCrypt sKeyHex "hex"

    // When EncryptSb is called, the contents of the source (sb)
    // remains unmodified.  The encrypted bytes are written into bdEncrypted.
    // If bdEncrypted already contained data, it is replaced with the encrypted bytes.
    Get Create (RefClass(cComChilkatBinData)) To hoBdEncrypted
    If (Not(IsComObjectCreated(hoBdEncrypted))) Begin
        Send CreateComObject of hoBdEncrypted
    End
    Get pvComObject of hoSb to vSb
    Get pvComObject of hoBdEncrypted to vBdEncrypted
    Get ComEncryptSb Of hoCrypt vSb vBdEncrypted To iSuccess
    If (iSuccess <> True) Begin
        Get ComLastErrorText Of hoCrypt To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // Examine the encrypted bytes:
    Get ComGetEncoded Of hoBdEncrypted "base64_mime" To sTemp1
    Showln sTemp1

    // Sample encrypted data:

    // 0DdNZ22ckMMJBiaKhAu3wUEfh16XW356NIUsDmNs/xwbHe/p1201OmpfzwXwKktkAefu2pckrBgC
    // df+1w8lRo+KAy5n5wlAgMGM/UrsVJsp0BmDPk1vaxKrmrGpSXOVCQs1n2+0atIs5YLiOG+Va3+Mi
    // EQNb4YK7bNMmvt0++irBxTiGnkx/RncfKwgkbBUpl2x7yV13MW6lapDT6Md0DKAMsTXFJYGeIdEf
    // g2uxDDQzI5gUOUHTMrXQ8paD/K76KKB9Jpp/kAM9z8g/d8KUmuphA7KI64d38xsgOmcITlbhlCQ2
    // PDkcU6RRzX0FUTUSMgQukhy0jkLZEjHX9poKJD+iJTOkcQUC3OqR9hKhSrvIgJN4lxdR71MheOoQ
    // 2wmvRdq+agTWWh333Vmb6J6yDV79aSpnqEDrA8Ks7Xzciol0gve91+JtVJlJKjWwEzWEU8GxF7Q8
    // eaWI70lsC5nTLGcbqgKu6gzkzHlHyHaE2FAQA/d5I2dvfsAYUQCza0Zdyw8mmTtHhlP2Tfxj1uPv
    // H4Q7BGuKnx3SWT2CnpbX4091w7KzLAztrbFBo/Tf9w8ZpgTK9k1ryfW9/xnk6rW6iQ==

    // Decrypt to restore back to the original:
    Get Create (RefClass(cComChilkatStringBuilder)) To hoSbOriginal
    If (Not(IsComObjectCreated(hoSbOriginal))) Begin
        Send CreateComObject of hoSbOriginal
    End
    Get pvComObject of hoBdEncrypted to vBdEncrypted
    Get pvComObject of hoSbOriginal to vSbOriginal
    Get ComDecryptSb Of hoCrypt vBdEncrypted vSbOriginal To iSuccess
    If (iSuccess <> True) Begin
        Get ComLastErrorText Of hoCrypt To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // Examine the original data:
    Get ComGetAsString Of hoSbOriginal To sTemp1
    Showln sTemp1

    // ----------------------------------------------------------------------------------
    // To do chacha20 encryption, just change the settings:

    Set ComCryptAlgorithm Of hoCrypt To "chacha20"
    Set ComKeyLength Of hoCrypt To 256
    // The initial count is the initial block counter for the chacha20 algorithm.
    // It can be any integer, but must be set to the same when decrypting.
    Set ComInitialCount Of hoCrypt To 22

    // EncryptSb completely replaces the contents of bdEncrypted.
    Get pvComObject of hoSb to vSb
    Get pvComObject of hoBdEncrypted to vBdEncrypted
    Get ComEncryptSb Of hoCrypt vSb vBdEncrypted To iSuccess

    // However.. DecryptSb appends the decrypted text to whatever may
    // have already existed within sbOriginal.
    Get pvComObject of hoBdEncrypted to vBdEncrypted
    Get pvComObject of hoSbOriginal to vSbOriginal
    Get ComDecryptSb Of hoCrypt vBdEncrypted vSbOriginal To iSuccess

    Showln "----"
    Showln "The original data should be here twice.  Once from the AES decrypt, and again from the chacha20 decrypt."
    Get ComGetAsString Of hoSbOriginal To sTemp1
    Showln sTemp1
    Showln "Success."


End_Procedure