Generate a Hash of the Message Body

This hash is used to validate the integrity of the message at the receiving end.

Follow these steps to generate the hash:

Generate the SHA-256 hash of the JSON payload (body of the message).

Encode the hashed string to Base64.

Prepend SHA-256=
to the front of the hash.

Add the message body hash to the

digest

header field.

Creating a Message Hash Using the Command Line

shasum

Tool

echo -n "{"clientReferenceInformation":{"code":"TC50171_3"},"paymentInformation":{"card":{"number":
				"4111111111111111","expirationMonth":"12","expirationYear":"2031"}},"orderInformation":{"amountDetails":
				{"totalAmount":"102.21","currency":"USD"},"billTo”:{“firstName":"John","lastName":"Doe","address1":
				"1MarketSt","locality":"sanfrancisco","administrativeArea":"CA","postalCode":"94105","country":"US",
				"email":"smartpayfusetest@barclaycard.co.uk","phoneNumber":"4158880000"}}}" | shasum -a 256

echo -n "6ae5459bc8a7d6a4b203e8a734d6a616725134088e13261f5bbcefc1424fc956" | base64

Creating a Message Hash Using the Command Line

base64

Tool

echo -n "6ae5459bc8a7d6a4b203e8a734d6a616725134088e13261f5bbcefc1424fc956" | base64

Creating a Message Hash Using C#

public static string GenerateDigest() {
				var digest = "";
				var bodyText = "{ your JSON payload }";
				using (var sha256hash = SHA256.Create()) {
				byte[] payloadBytes = sha256hash
				.ComputeHash(Encoding.UTF8.GetBytes(bodyText));
				digest = Convert.ToBase64String(payloadBytes);
				digest = "SHA-256=" + digest;
				}
				return digest;
				}

Creating a Message Using Java

public static String GenerateDigest() throws NoSuchAlgorithmException {
				String bodyText = "{ your JSON payload }";
				MessageDigest md = MessageDigest.getInstance("SHA-256");
				md.update(bodyText.getBytes(StandardCharsets.UTF_8));
				byte[] digest = md.digest();
				return "SHA-256=" + Base64.getEncoder().encodeToString(digest);
				}

Digest Header Field

digest: SHA-256=NmFlNTQ1OWJjOGE3ZDZhNGIyMDNlOGE3MzRkNmE2MTY3MjUxMzQwODhlMTMyNjFmNWJiY2VmYzE0MjRmYzk1Ng==