Generating HMAC-SHA256 with Postman

The information below can be used to generate a signature with Postman to test Therefore™ webhooks.

1. First, set up the webhook in Postman and go to the Scripts tab. Select 'Pre-request'.

   

2. Add the following scripts:

   HMAC-SHA256 in a header as hex-encoded string

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   const crypto = pm.require('npm:crypto-js@4.2.0');
   var signBytes = crypto.HmacSHA256(pm.request.body.raw, 'test');
   var signHex = crypto.enc.Hex.stringify(signBytes);
   pm.request.headers.add({
       key: "X-Signature",
       value: signHex
   });

   Secret

   The 'test' string represents the secret

   Header Name

   The 'X-Signature' string is the header name that will be used as part of the signature

   HMAC-SHA256 in a header as base64-encoded string

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   const crypto = pm.require('npm:crypto-js@4.2.0');
   var signBase64 = crypto.HmacSHA256(pm.request.body.raw, 'test').toString(crypto.enc.Base64);
   
   pm.request.headers.add({
       key: "X-Signature",
       value: signBase64
   });

   Secret

   The 'test' string represents the secret

   Header Name

   The 'X-Signature' string is the header name that will be used as part of the signature

   HMAC-SHA256 with unix timestamp as part of the header

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   const crypto = pm.require('npm:crypto-js@4.2.0');
   var current = new Date();
   var timestamp = Math.floor(current.getTime() / 1000)
   var sign = timestamp + '.' + pm.request.body.raw;
   var signBytes = crypto.HmacSHA256(sign, 'test');
   var signHex = crypto.enc.Hex.stringify(signBytes);
   var sigHeader = "t=" + timestamp + ",v1=" + signHex;
   pm.request.headers.add({
       key: "X-Signature",
       value: sigHeader
   });

   HMAC-SHA256 with unix timestamp in a separate header

   Copy

   const crypto = pm.require('npm:crypto-js@4.2.0');
   var current = new Date();
   var timestamp = Math.floor(current.getTime() / 1000)
   pm.request.headers.add({
       key: "X-Timestamp",
       value: timestamp
   });
   
   var signBytes = crypto.HmacSHA256(timestamp + "." +pm.request.body.raw, 'test');
   var signHex = crypto.enc.Hex.stringify(signBytes);
   pm.request.headers.add({
       key: "X-Signature",
       value: signHex
   });