Browser Encryption

The app encrypts data for browser handoff using AES-CBC with PBKDF2 key derivation. This is used when the app needs to pass authentication context to a browser session.

Algorithm

Found in KeyChainManager.encryptTextForBrowser():

Algorithm: AES/CBC/PKCS5PADDING
Key derivation: PBKDF2WithHmacSHA1
  - Passphrase: serverPassphrase (received from server)
  - Salt: serverSalt (hex string, received from server)
  - Iterations: 1000
  - Key length: 128 bits
IV: serverIv (hex string, received from server)
Output: Base64 -> URI-encoded

Encrypted Payload Format

$id_dispositivo:<device_id>
$password_dispositivo:<device_password>
$url_destino:<target_url>
$idioma:<lang>_ES
[$NIF:<nif>]
[$datoContraste:<contrast_data>$tipoAutenticacion:<auth_type>]
[$codigo:<code>$pin:<pin>]

Fields in brackets are optional and included depending on the context.

Key Points

• All encryption parameters (serverPassphrase, serverIv, serverSalt) come from the server, making this a server-controlled scheme.
• The output is Base64-encoded, then URI-encoded for transmission.
• This is only used for browser handoff scenarios -- not for general API communication.

SAML Form-Based Flow

The DNIe path through pasarela.clave.gob.es uses standard SAML redirects:

• No custom crypto beyond TLS mutual auth with the DNIe certificate
• The eID card provides the SSLSocketFactory for client certificate authentication
• Forms contain SAMLResponse fields for assertion relay

See SAML / DNIe Authentication for the full flow.