(DataFlex) Duplicate PHP's openssl_encrypt and openssl_random_pseudo_bytes

Demonstrates how to duplicate PHP's openssl_encrypt function. (https://www.php.net/manual/en/function.openssl-encrypt.php)

For more information, see https://www.php.net/manual/en/function.openssl-encrypt.php

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

Use ChilkatAx-win32.pkg

Procedure Test
    Boolean iSuccess
    Handle hoCrypt
    String sText
    String sPassphrase
    String sIvBase64
Key    Handle hoBdKey
    Integer iSz
    String sCipherText64
    Handle hoBd
    String sResult
Result    Handle hoBdResult
    String sOriginalText
    String sTemp1

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

    // Duplicates thw following PHP script:

    // $text = "This is a test";
    // $passphrase = "my password";
    // $iv = openssl_random_pseudo_bytes(openssl_cipher_iv_length("AES-256-CBC"));
    // $crypted = base64_encode($iv.openssl_encrypt($text, "AES-256-CBC", $passphrase, OPENSSL_RAW_DATA, $iv));
    // echo $crypted;

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

    Move "This is a test" To sText
    Move "my password" To sPassphrase

    // AES is a block cipher.  The IV size for any block cipher is the size of the block, which is defined by the encryption algorithm. 
    // For AES, the block size is always 16 bytes, regardless of key size (i.e. 128-bits, 192-bits, or 256-bits).
    // Therefore, generate 16 random bytes for the IV.
    Set ComEncodingMode Of hoCrypt To "base64"
    Get ComGenRandomBytesENC Of hoCrypt 16 To sIvBase64

    Showln "Generated IV = " sIvBase64

    // Because we're doing AES-256-CBC, the key length must be 256-bits (i.e. 32 bytes).
    // Given that our passphrase is a us-ascii string that can be shorter or longer than 32-bytes, we need to 
    // somehow transform the passphrase to a 32-byte secret key.  We need to know what openssl_encrypt does.
    // Here's the answer from the openssl_encrypt documentation:
    // 
    // "If the passphrase is shorter than expected, it is silently padded with NUL characters; 
    // if the passphrase is longer than expected, it is silently truncated."

    // OK.... so let's pad or shorten to get a 32-byte key.
    Get Create (RefClass(cComChilkatBinData)) To hoBdKey
    If (Not(IsComObjectCreated(hoBdKey))) Begin
        Send CreateComObject of hoBdKey
    End
    Get ComAppendString Of hoBdKey sPassphrase "utf-8" To iSuccess

    Get ComNumBytes Of hoBdKey To iSz
    If (iSz > 32) Begin
        Get ComRemoveChunk Of hoBdKey 32 (iSz - 32) To iSuccess
    End
    Else Begin
        Get ComClear Of hoBdKey To iSuccess
        Get ComAppendPadded Of hoBdKey sPassphrase "utf-8" False 32 To iSuccess
    End

    // Setup for encryption.
    Set ComCryptAlgorithm Of hoCrypt To "aes"
    Set ComKeyLength Of hoCrypt To 256
    Send ComSetEncodedIV To hoCrypt sIvBase64 "base64"
    Get ComGetEncoded Of hoBdKey "base64" To sTemp1
    Send ComSetEncodedKey To hoCrypt sTemp1 "base64"

    // Encrypt and base64 encode.
    Get ComEncryptStringENC Of hoCrypt sText To sCipherText64

    // The PHP code fragment above returns the base64 encoded bytes of the IV and the encrypted text.
    // So let's do that..
    Get Create (RefClass(cComChilkatBinData)) To hoBd
    If (Not(IsComObjectCreated(hoBd))) Begin
        Send CreateComObject of hoBd
    End
    Get ComAppendEncoded Of hoBd sIvBase64 "base64" To iSuccess
    Get ComAppendEncoded Of hoBd sCipherText64 "base64" To iSuccess
    Get ComGetEncoded Of hoBd "base64" To sResult

    Showln "result = " sResult

    // Sample output:
    // dN0vS1O0cWi5BbLAAY+NTf7bs3S27xzPf11RkG47sjs=

    // Now let's decrypt from the output...

    // Setup for decryption.
    Set ComCryptAlgorithm Of hoCrypt To "aes"
    Set ComKeyLength Of hoCrypt To 256
    Get ComGetEncoded Of hoBdKey "base64" To sTemp1
    Send ComSetEncodedKey To hoCrypt sTemp1 "base64"

    Get Create (RefClass(cComChilkatBinData)) To hoBdResult
    If (Not(IsComObjectCreated(hoBdResult))) Begin
        Send CreateComObject of hoBdResult
    End
    Get ComAppendEncoded Of hoBdResult sResult "base64" To iSuccess
    Get ComGetEncodedChunk Of hoBdResult 0 16 "base64" To sTemp1
    Send ComSetEncodedIV To hoCrypt sTemp1 "base64"

    // Remove the IV (first 16 bytes) from the result.
    Get ComRemoveChunk Of hoBdResult 0 16 To iSuccess
    Get pvComObject of hoBdResult to vBdResult
    Get ComDecryptBd Of hoCrypt vBdResult To iSuccess
    Get ComGetString Of hoBdResult "utf-8" To sOriginalText

    Showln "original text = " sOriginalText


End_Procedure