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(C#) Duplicate PHP's openssl_encrypt and openssl_random_pseudo_bytesDemonstrates 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
// 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; bool success; Chilkat.Crypt2 crypt = new Chilkat.Crypt2(); string text = "This is a test"; string passphrase = "my password"; // 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. crypt.EncodingMode = "base64"; string ivBase64 = crypt.GenRandomBytesENC(16); Debug.WriteLine("Generated IV = " + ivBase64); // 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. Chilkat.BinData bdKey = new Chilkat.BinData(); bdKey.AppendString(passphrase,"utf-8"); int sz = bdKey.NumBytes; if (sz > 32) { bdKey.RemoveChunk(32,sz - 32); } else { bdKey.Clear(); bdKey.AppendPadded(passphrase,"utf-8",false,32); } // Setup for encryption. crypt.CryptAlgorithm = "aes"; crypt.KeyLength = 256; crypt.SetEncodedIV(ivBase64,"base64"); crypt.SetEncodedKey(bdKey.GetEncoded("base64"),"base64"); // Encrypt and base64 encode. string cipherText64 = crypt.EncryptStringENC(text); // The PHP code fragment above returns the base64 encoded bytes of the IV and the encrypted text. // So let's do that.. Chilkat.BinData bd = new Chilkat.BinData(); bd.AppendEncoded(ivBase64,"base64"); bd.AppendEncoded(cipherText64,"base64"); string result = bd.GetEncoded("base64"); Debug.WriteLine("result = " + result); // Sample output: // dN0vS1O0cWi5BbLAAY+NTf7bs3S27xzPf11RkG47sjs= // Now let's decrypt from the output... // Setup for decryption. crypt.CryptAlgorithm = "aes"; crypt.KeyLength = 256; crypt.SetEncodedKey(bdKey.GetEncoded("base64"),"base64"); Chilkat.BinData bdResult = new Chilkat.BinData(); bdResult.AppendEncoded(result,"base64"); crypt.SetEncodedIV(bdResult.GetEncodedChunk(0,16,"base64"),"base64"); // Remove the IV (first 16 bytes) from the result. bdResult.RemoveChunk(0,16); success = crypt.DecryptBd(bdResult); string originalText = bdResult.GetString("utf-8"); Debug.WriteLine("original text = " + originalText); |
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