> For the complete documentation index, see [llms.txt](https://apis.payon.com.kh/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://apis.payon.com.kh/message-cryptography/encryption-library-api-secification.md).

# Encryption Library API Secification

@Payon development group

4.1.1 Data 

{% tabs %}
{% tab title="PHP" %}

| Function                                | Explanation                                                                                                                                                                                                                   |
| --------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| function createSession($termId, $txnId) | <p>Encrypted session creation between client and server</p><ol><li><p>Input Param</p><p>1.1 termId: Terminal ID given by PayOn</p><p>1.2 txnId: Merchant transaction identification number</p></li><li>Return: none</li></ol> |
| function PayOnEncrypt($data)            | <p>Data encryption</p><ol><li><p>Input Param</p><p>1.1 data: Data to be encrypted</p></li><li>Return: Encrypted data</li></ol>                                                                                                |
| function PayOnDecrypt($data)            | <p>Data decryption</p><ol><li><p>Input Param</p><p>1.1 data: Data to be decrypted</p></li><li>Return: Decrypted data</li></ol>                                                                                                |
| function PayOnGenerateMAC($data)        | <p>Generate MAC value for message verification</p><ol><li><p>Input Param</p><p>1.1 data: MAC Data for generation</p></li><li>return: MAC value for message verification.</li></ol>                                            |
| {% endtab %}                            |                                                                                                                                                                                                                               |

{% tab title="Java or .NET" %}

| Function                                   | Explanation                                                                                                                                                                                                                                                                             |
| ------------------------------------------ | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| String getVersion()                        | <p>Library version lookup</p><ol><li>Input Param: none</li><li>Return: Library </li></ol>                                                                                                                                                                                               |
| void createSession(termId, txnId)          | <p>Encrypted session creation between client and server</p><ol><li><p>Input Param</p><p>1.1 termId: Terminal ID given by PayOn</p><p>1.2 txnId: Merchant transaction identification number</p></li><li>Return: none</li></ol>                                                           |
| String PayOnEncrypt(data, isHexString)     | <p>Data encryption</p><ol><li><p>Input Param</p><p>1.1 data: Data to be encrypted<br>1.2 isHexString: False if the data to be encrypted is a general string, true if it is a Hex String.</p></li><li>Return: Encrypted data</li></ol>                                                   |
| String PayOnDecrypt(data)                  | <p>Data decryption</p><ol><li><p>Input Param</p><p>1.1 data: Data to be decrypted</p></li><li>Return: Decrypted data</li></ol>                                                                                                                                                          |
| String PayOnGenerateMAC(data, isHexString) | <p>Generate MAC value for message verification</p><ol><li><p>Input Param</p><p>1.1 data: MAC Data for generation<br>1.2 isHexString: False if the data to be encrypted is general string, true if it is a Hex String.</p></li><li>return: MAC value for message verification.</li></ol> |
| {% endtab %}                               |                                                                                                                                                                                                                                                                                         |
| {% endtabs %}                              |                                                                                                                                                                                                                                                                                         |

4.1.2 Message Encryption Example

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{% tab title="PHP" %}

```
$payOnCipher = new PayOnCipher();
$payOnCipher->createSession($termId, $txnId);
$encryptData = $payOnCipher->PayOnEncrypt($data);
```

{% endtab %}

{% tab title="Java or .NET" %}

```
PayOnCipher cp = new PayOnCipher();
cp.createSession(termId, txnId);
String encryptData = cp.PayOnEncrypt(data, false);
```

{% endtab %}
{% endtabs %}

4.1.3 Message Decryption Example

{% tabs %}
{% tab title="PHP" %}

```
$payOnCipher = new PayOnCipher();
$payOnCipher->createSession($termId, $txnId);
$decryptData = $payOnCipher->PayOnDecrypt($data);
```

{% endtab %}

{% tab title="Java or .NET" %}

```
PayOnCipher cp = new PayOnCipher();
cp.createSession(termId, txnId);
String decryptData = cp.PayOnDecrypt(data);
```

{% endtab %}
{% endtabs %}

4.1.3 Message Generate MAC Example

{% tabs %}
{% tab title="PHP" %}

```
$payOnCipher = new PayOnCipher();
$payOnCipher->createSession($termId, $txnId);
$mac = $payOnCipher->PayOnGenerateMAC($data);
```

{% endtab %}

{% tab title="Java or .NET" %}

```
cp = new PayOnCipher();
cp.createSession(termId, txnId);
String mac = cp.PayOnGenerateMAC(data);
```

{% endtab %}
{% endtabs %}