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Ibanity HTTP Signature for XS2A, Isabel Connect, Ponto Connect

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

Chilkat C Downloads

C
#include <C_CkJsonObject.h>
#include <C_CkDateTime.h>
#include <C_CkCrypt2.h>
#include <C_CkStringBuilder.h>
#include <C_CkPrivateKey.h>
#include <C_CkRsa.h>

void ChilkatSample(void)
    {
    BOOL success;
    HCkJsonObject json;
    const char *payload;
    HCkDateTime dtNow;
    const char *created;
    HCkCrypt2 crypt;
    HCkStringBuilder sbDigestHdrValue;
    const char *request_target;
    HCkStringBuilder sbSigningString;
    const char *idempotencyKey;
    const char *signed_headers_list;
    HCkPrivateKey privKey;
    HCkRsa rsa;
    const char *sigBase64;
    HCkStringBuilder sbSigHeaderValue;

    success = FALSE;

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

    // 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
    json = CkJsonObject_Create();
    CkJsonObject_UpdateString(json,"data.type","customerAccessToken");
    CkJsonObject_UpdateString(json,"data.attributes.applicationCustomerReference","15874569");

    payload = CkJsonObject_emit(json);
    printf("payload = %s\n",payload);

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

    dtNow = CkDateTime_Create();
    CkDateTime_SetFromCurrentSystemTime(dtNow);
    created = CkDateTime_getAsUnixTimeStr(dtNow,FALSE);
    printf("created = %s\n",created);

    // Step 2: Build the Digest header
    crypt = CkCrypt2_Create();
    CkCrypt2_putHashAlgorithm(crypt,"sha512");
    CkCrypt2_putEncodingMode(crypt,"base64");
    CkCrypt2_putCharset(crypt,"utf-8");

    sbDigestHdrValue = CkStringBuilder_Create();
    CkStringBuilder_Append(sbDigestHdrValue,"SHA-512=");
    CkStringBuilder_Append(sbDigestHdrValue,CkCrypt2_hashStringENC(crypt,CkJsonObject_emit(json)));

    printf("%s\n",CkStringBuilder_getAsString(sbDigestHdrValue));

    // 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.
    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. 

    sbSigningString = CkStringBuilder_Create();
    CkStringBuilder_Append(sbSigningString,"(request-target): ");
    CkStringBuilder_AppendLine(sbSigningString,request_target,FALSE);
    CkStringBuilder_Append(sbSigningString,"host: ");
    CkStringBuilder_AppendLine(sbSigningString,"api.ibanity.com",FALSE);
    CkStringBuilder_Append(sbSigningString,"digest: ");
    CkStringBuilder_AppendLine(sbSigningString,CkStringBuilder_getAsString(sbDigestHdrValue),FALSE);
    CkStringBuilder_Append(sbSigningString,"(created): ");
    CkStringBuilder_AppendLine(sbSigningString,created,FALSE);
    CkStringBuilder_Append(sbSigningString,"ibanity-idempotency-key: ");
    idempotencyKey = CkCrypt2_generateUuid(crypt);
    CkStringBuilder_Append(sbSigningString,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. 
    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.

    privKey = CkPrivateKey_Create();
    success = CkPrivateKey_LoadEncryptedPemFile(privKey,"my_ibanity_signature_private_key.pem","pem_password");
    if (success == FALSE) {
        printf("%s\n",CkPrivateKey_lastErrorText(privKey));
        CkJsonObject_Dispose(json);
        CkDateTime_Dispose(dtNow);
        CkCrypt2_Dispose(crypt);
        CkStringBuilder_Dispose(sbDigestHdrValue);
        CkStringBuilder_Dispose(sbSigningString);
        CkPrivateKey_Dispose(privKey);
        return;
    }

    rsa = CkRsa_Create();
    CkRsa_putPssSaltLen(rsa,32);
    CkRsa_putEncodingMode(rsa,"base64");
    // Use the RSASSA-PSS signature algorithm
    CkRsa_putPkcsPadding(rsa,FALSE);

    success = CkRsa_UsePrivateKey(rsa,privKey);
    if (success == FALSE) {
        printf("%s\n",CkRsa_lastErrorText(rsa));
        CkJsonObject_Dispose(json);
        CkDateTime_Dispose(dtNow);
        CkCrypt2_Dispose(crypt);
        CkStringBuilder_Dispose(sbDigestHdrValue);
        CkStringBuilder_Dispose(sbSigningString);
        CkPrivateKey_Dispose(privKey);
        CkRsa_Dispose(rsa);
        return;
    }

    // Sign the signing string.
    sigBase64 = CkRsa_signStringENC(rsa,CkStringBuilder_getAsString(sbSigningString),"sha-256");
    if (CkRsa_getLastMethodSuccess(rsa) == FALSE) {
        printf("%s\n",CkRsa_lastErrorText(rsa));
        CkJsonObject_Dispose(json);
        CkDateTime_Dispose(dtNow);
        CkCrypt2_Dispose(crypt);
        CkStringBuilder_Dispose(sbDigestHdrValue);
        CkStringBuilder_Dispose(sbSigningString);
        CkPrivateKey_Dispose(privKey);
        CkRsa_Dispose(rsa);
        return;
    }

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

    printf("%s\n",CkStringBuilder_getAsString(sbSigHeaderValue));


    CkJsonObject_Dispose(json);
    CkDateTime_Dispose(dtNow);
    CkCrypt2_Dispose(crypt);
    CkStringBuilder_Dispose(sbDigestHdrValue);
    CkStringBuilder_Dispose(sbSigningString);
    CkPrivateKey_Dispose(privKey);
    CkRsa_Dispose(rsa);
    CkStringBuilder_Dispose(sbSigHeaderValue);

    }