Encrypting the tax id
List Accounts accepts the member's tax id as customer_uuid, encrypted with the public key Casap issued to your organization:
| Step | Requirement |
|---|---|
| Encrypt | RSA-OAEP with SHA-256 as both the OAEP and MGF1 digest |
| Encode | Base64 the ciphertext |
| Send | Percent-encode the base64 before putting it in the query string |
Two common failures:
- Many OAEP libraries default MGF1 to SHA-1. That ciphertext cannot be decrypted, and the API reports only a generic "not a recognized customer identifier" error.
- Raw base64 contains
+,/, and=, which break query strings unless percent-encoded.