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hmac helper

Tom Santiago
Updated

Use {{hmac}} to generate an HMAC (keyed-hash message authentication code) from a given field or string, using a secret key and a supported hash algorithm. This verifies data integrity and authenticity when sending requests.

Usage

{{hmac "algorithm" key "encoding" field keyEncoding}}

  • algorithm: One of Celigo’s supported cryptographic algorithms (e.g., "sha256", "sha1", "md5").

  • key: The path to your secret key in dot notation (e.g., connection.http.encrypted.secretKey).

  • encoding: The format of the resulting HMAC (e.g., "hex" or "base64").

  • field: The string or field path whose value you want to authenticate.

  • keyEncoding (optional): How the secret key is encoded ("utf8" or "base64"). Defaults to "utf8" if not specified.

Note

See Using hmacOptions for additional functionality.

Examples

  1. HMAC-SHA256 with a secure key 

    {{hmac "sha256" connection.http.encrypted.secretKey "hex" record.payload}}

    • Uses the secret key in connection.http.encrypted.secretKey

    • Produces a hex-encoded SHA-256 HMAC of record.payload

  2. Base64-encoded key and field 

    {{hmac "sha1" connection.http.encrypted.secretKey "base64" record.body "base64"}}

    • Interprets the secret key as base64

    • Returns a base64-encoded SHA-1 signature of record.body

Tip

  • Secure your secret key: Always store it in encrypted fields to prevent exposure (e.g., connection.http.encrypted).

  • Use HTTPS: HMAC is most effective when transmitted securely over HTTPS.

  • URI-encode parameters if your authentication scheme requires signing the entire URL, including query parameters.

  • No dot notation for the HMAC result: The field parameter must be a direct string or field path; referencing nested objects (e.g., record.property) typically works, but passing the result of hmac further with dot notation is not supported.

  • For additional control (e.g., signing a full URL or customizing the signature process), see hmacOptions in Celigo’s documentation.