Signature Algorithm

The signature is an HMAC-SHA256 hex digest (lowercase) of the following message, using the validation key as the HMAC secret:

Where:

• key — the validation key provided by SnapScan (used as both the HMAC secret and embedded in the message)
• amount — the integer amount in cents (same value passed in the URL)
• id — the order reference (same value passed in the URL)
• || — double pipe delimiters