(C++) Ibanity HTTP Signature for XS2A, Isabel Connect, Ponto Connect

See more Ibanity Examples

Demonstrates how to add a Signature header for Ibanity HTTP requests.

For more information, see https://documentation.ibanity.com/http-signature

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#include <CkJsonObject.h>
#include <CkDateTime.h>
#include <CkCrypt2.h>
#include <CkStringBuilder.h>
#include <CkPrivateKey.h>
#include <CkRsa.h>

void ChilkatSample(void)
    {
    // This example requires the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    bool success;

    // In order to sign your HTTP requests, you have to add 2 headers to the HTTP request: Digest: the digest of the request payload and Signature: the actual signature of the request. 

    // POST /xs2a/customer-access-tokens HTTP/1.1
    // Host: api.ibanity.com
    // Content-Type: application/json
    // Digest: SHA-512=z4PhNX7vuL3xVChQ1m2AB9Yg5AULVxXcg/SpIdNs6c5H0NE8XYXysP+DGNKHfuwvY7kxvUdBeoGlODJ6+SfaPg==
    // Ibanity-Idempotency-Key: 61f02718-eeee-46e1-b5eb-e8fd6e799c2d
    // Signature: keyId="62f02718-eeee-46e1-b5eb-e8fd6e799c2e",created=1599659223,algorithm="hs2019",headers="(request-target) host digest (created) ibanity-idempotency-key",signature="SjWJWbWN7i0...zsbM="
    // 
    // {"data":{"type":"customerAccessToken", "attributes":{"applicationCustomerReference":"15874569"}}}

    // The payload (body) of the above HTTP request is the JSON.
    // Build the JSON above.
    // Use this online tool to generate code from sample JSON: 
    // Generate Code to Create JSON
    CkJsonObject json;
    json.UpdateString("data.type","customerAccessToken");
    json.UpdateString("data.attributes.applicationCustomerReference","15874569");

    const char *payload = json.emit();
    std::cout << "payload = " << payload << "\r\n";

    // Step 1: Build the (created) virtual header

    CkDateTime dtNow;
    dtNow.SetFromCurrentSystemTime();
    const char *created = dtNow.getAsUnixTimeStr(false);
    std::cout << "created = " << created << "\r\n";

    // Step 2: Build the Digest header
    CkCrypt2 crypt;
    crypt.put_HashAlgorithm("sha512");
    crypt.put_EncodingMode("base64");
    crypt.put_Charset("utf-8");

    CkStringBuilder sbDigestHdrValue;
    sbDigestHdrValue.Append("SHA-512=");
    sbDigestHdrValue.Append(crypt.hashStringENC(json.emit()));

    std::cout << sbDigestHdrValue.getAsString() << "\r\n";

    // Step 3: Build the (request target) virtual header

    // In order to build the signature you will need a virtual header named (request-target) (the parentheses are important). 
    // The (request-target) is the string concatenation of the HTTP method (in lowercase) with the path and query parameters.
    const char *request_target = "post /xs2a/customer-access-tokens";

    // Step 4: Build the signing string

    // The signing string is the concatenation of the signed header names (in lowercase) and values separated by a LF.

    // You must always sign the following headers: (request-target), host, (created), digest. 
    // If used, you must also sign the authorization header and any ibanity-* headers, such as ibanity-idempotency-key. 

    CkStringBuilder sbSigningString;
    sbSigningString.Append("(request-target): ");
    sbSigningString.AppendLine(request_target,false);
    sbSigningString.Append("host: ");
    sbSigningString.AppendLine("api.ibanity.com",false);
    sbSigningString.Append("digest: ");
    sbSigningString.AppendLine(sbDigestHdrValue.getAsString(),false);
    sbSigningString.Append("(created): ");
    sbSigningString.AppendLine(created,false);
    sbSigningString.Append("ibanity-idempotency-key: ");
    const char *idempotencyKey = crypt.generateUuid();
    sbSigningString.Append(idempotencyKey);

    // Step 5: Build the signed headers list

    // To allow Ibanity to check the signed headers, you must provide a list of the header names. They should be lowercase and in the same order used to create the signing string. 
    const char *signed_headers_list = "(request-target) host digest (created) ibanity-idempotency-key";

    // Step 6: Build the Signature header

    // This is where the real signing happens. The signature header is a combination of several sub-headers -
    // 
    //     keyId: the identifier for the application's signature certificate, obtained from the Developer Portal
    //     algorithm: the digital signature algorithm used to generate the signature (must be hs2019)
    //     headers: The list of HTTP headers created in step 5
    //     signature: the Base64-encoded digital signature of the signing string created in step 4.

    CkPrivateKey privKey;
    success = privKey.LoadEncryptedPemFile("my_ibanity_signature_private_key.pem","pem_password");
    if (success == false) {
        std::cout << privKey.lastErrorText() << "\r\n";
        return;
    }

    CkRsa rsa;
    rsa.put_PssSaltLen(32);
    rsa.put_EncodingMode("base64");
    // Use the RSASSA-PSS signature algorithm
    rsa.put_OaepPadding(true);

    success = rsa.ImportPrivateKeyObj(privKey);
    if (success == false) {
        std::cout << rsa.lastErrorText() << "\r\n";
        return;
    }

    // Sign the signing string.
    const char *sigBase64 = rsa.signStringENC(sbSigningString.getAsString(),"sha-256");
    if (rsa.get_LastMethodSuccess() == false) {
        std::cout << rsa.lastErrorText() << "\r\n";
        return;
    }

    // Build the signature header value.
    CkStringBuilder sbSigHeaderValue;
    sbSigHeaderValue.Append("keyId=\"");
    // Use your identifier for the application's signature certificate, obtained from the Developer Portal
    sbSigHeaderValue.Append("62f02718-eeee-46e1-b5eb-e8fd6e799c2e");
    sbSigHeaderValue.Append("\",created=");
    sbSigHeaderValue.Append(created);
    sbSigHeaderValue.Append(",algorithm=\"hs2019\",headers=\"");
    sbSigHeaderValue.Append(signed_headers_list);
    sbSigHeaderValue.Append("\",signature=\"");
    sbSigHeaderValue.Append(sigBase64);
    sbSigHeaderValue.Append("\"");

    std::cout << sbSigHeaderValue.getAsString() << "\r\n";
    }