RSA encrypted authData

Here we show you how to encrypt sensitive data for all APIs that transmit debit/credit card information

authData is an RSA encrypted field used to securely transmit sensitive payment data.

It comprises the card number (PAN), CVV, Card expiry date (YYMM), token (1=true, 0=false)

See sample Java code snippets below for implementing the RSA encryption of the authData field

📘

You can use either code snippet

Sample RSA code snippet

public static PublicKey getPublicKey(String modulus, String publicExponent)  throws Exception
    {
     Security.addProvider(new BouncyCastleProvider());
  RSAPublicKeySpec publicKeyspec = new RSAPublicKeySpec(new BigInteger(modulus, 16), new BigInteger(publicExponent, 16));
  KeyFactory factory = KeyFactory.getInstance("RSA"); //, "JHBCI");
  PublicKey publicKey = factory.generatePublic(publicKeyspec);
  return publicKey;
    }

Java

public static String getAuthDataMerchant(String version, String pan, String expiryDate, String cvv2) throws Exception
    {
     String authData = "";
     String authDataCipher = pan + "D" + cvv2 + "D" + expiryDate;
     System.out.println("Auth Data Cipher: " + authDataCipher);
     // The Modulus and Public Exponent will be supplied by Interswitch. please ask for one
  String modulus = "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";
  String publicExponent = "010001";
  PublicKey publicKey = getPublicKey(modulus, publicExponent);
  
  System.out.println("================================================================================");
  System.out.println("Generated Signature: \n");
  System.out.println(publicKey + "\n");
  
  Cipher encryptCipher = Cipher.getInstance("RSA/ECB/PKCS1Padding", "BC");
  encryptCipher.init(Cipher.ENCRYPT_MODE, publicKey);
     byte[] authDataBytes = encryptCipher.doFinal(authDataCipher.getBytes("UTF8"));
//     authData = Base64.getEncoder().encodeToString(authDataBytes).replaceAll("\\r|\\n", "");
//     authData = new String(new org.apache.commons.codec.binary.Hex().encode(authDataBytes)).toUpperCase();
     authData = new String(org.bouncycastle.util.encoders.Base64.encode(authDataBytes)).trim();
     return authData;
    }

Sample RSA code snippet for Token Transactions

public static String getTokenAuthData(String version, String token) throws Exception
    {
    	String authData = "";
    	String authDataCipher = token+",";
    	System.out.println("Auth Data Cipher: " + authDataCipher);
    	// The Modulus and Public Exponent will be supplied by Interswitch. please ask for one
    	String modulus = "9c7b3ba621a26c4b02f48cfc07ef6ee0aed8e12b4bd11c5cc0abf80d5206be69e1891e60fc88e2d565e2fabe4d0cf630e318a6c721c3ded718d0c530cdf050387ad0a30a336899bbda877d0ec7c7c3ffe693988bfae0ffbab71b25468c7814924f022cb5fda36e0d2c30a7161fa1c6fb5fbd7d05adbef7e68d48f8b6c5f511827c4b1c5ed15b6f20555affc4d0857ef7ab2b5c18ba22bea5d3a79bd1834badb5878d8c7a4b19da20c1f62340b1f7fbf01d2f2e97c9714a9df376ac0ea58072b2b77aeb7872b54a89667519de44d0fc73540beeaec4cb778a45eebfbefe2d817a8a8319b2bc6d9fa714f5289ec7c0dbc43496d71cf2a642cb679b0fc4072fd2cf";
		String publicExponent = "010001";
		PublicKey publicKey = getPublicKey(modulus, publicExponent);
		
		System.out.println("================================================================================");
		System.out.println("Generated Signature: \n");
		System.out.println(publicKey + "\n");
		
		Cipher encryptCipher = Cipher.getInstance("RSA/ECB/PKCS1Padding", "BC");
		encryptCipher.init(Cipher.ENCRYPT_MODE, publicKey);
    	byte[] authDataBytes = encryptCipher.doFinal(authDataCipher.getBytes("UTF8"));
//    	authData = Base64.getEncoder().encodeToString(authDataBytes).replaceAll("\\r|\\n", "");
//    	authData = new String(new org.apache.commons.codec.binary.Hex().encode(authDataBytes)).toUpperCase();
    	authData = new String(org.bouncycastle.util.encoders.Base64.encode(authDataBytes)).trim();
    	return authData;
    }