Email is insecure, despite what many may lead you to think. You should not send confidential information in emails. This includes attachments. See Wikipedia's entry on E-mail privacy for additional information.
Send File Securely was created to solve the problem of insecure email. By using the latest cryptographic and secure programming standards, Send Files Securely provides a secure way to transfer files online without the need to install or configure any software. You simply upload your files and let it take care of the rest.
For more information about Send Files Securely's security, please see Why Use Send Files Securely and Technical Security Overview. Also, please feel free to contact me and I'll personally answer any questions you have.
Best Regards,
Andrew, CISSP
Creator of Send Files Securely