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Card-encryption

Encryption And Authentication​

AES Card Encryption (what To Encrypt And How)​

The card field in the Payments API is not plain card data.

It must be an AES-encrypted value of the string below:

<CardNumber>.<Month>.<Year>.<CVV>

Then Base64-encode the encrypted bytes.

Simpaisa decrypts the value using the same secretKey configured for your merchant.

info

AES keys must be 16 / 24 / 32 bytes long (AES-128 / AES-192 / AES-256).

In Java, Cipher.getInstance("AES") usually resolves to AES/ECB/PKCS5Padding.

Sample AES Encryption Code (Java)​

AES encryption helper (Java)
public static String encrypt(final String secret, final String data) {
    // byte[] decodedKey = Base64.getDecoder().decode(secret);

    try {
        setKey(secret);
        Cipher cipher = Cipher.getInstance("AES");
        // rebuild key using SecretKeySpec

        cipher.init(Cipher.ENCRYPT_MODE, secretKey);
        byte[] cipherText = cipher.doFinal(data.getBytes("UTF-8"));
        return Base64.getEncoder().encodeToString(cipherText);
    } catch (Exception e) {
        throw new RuntimeException("Error occured while encrypting data", e);
    }
}