When a message is to be transmitted to an intended recipient, a validation code may be incorporated into the message. The validation code, which may include, for example, a random string of alphanumeric characters or a time of day, also is transmitted to a central facility in a secure manner. A query that incorporates the validation code may be extracted from the message and sent to the central facility either by equipment associated with the intended recipient of the message or by a service provider that intercepts the message. The central facility can use the validation code to verify, with a relatively high degree of likelihood, whether the message was sent by the particular entity associated with the identification code. The central facility then can inform the intended recipient (or the service provider) whether the message was properly verified. To ensure that the central facility will be able to verify, with a relatively high degree of likelihood, that the message was sent by a valid holder of the identification code, the validation code may be encrypted before being sent to the central facility or it may be transmitted to the central facility, for example, over a virtual private network.