What are security envelopes?
Security envelopes are specially designed envelopes that have patterns printed on the interior surface to prevent the contents from being visible when held up to light to protect the confidentiality and integrity of their contents. These envelopes are commonly used for mailing sensitive information, such as financial documents, legal papers, personal correspondence, and other confidential materials.

The designs typically consist of intricate patterns, grids, or lettering that obscure the contents of the envelope.
Another common design feature is tamper-evident closures. These closures are designed to show visible signs of interference if someone attempts to open the envelope. For example, some envelopes use adhesive seals that tear the paper when opened, while others may include a warning message that becomes visible if the seal is broken.

High-security envelopes used for specific applications, like ballot mailing or corporate documents, may include barcodes, watermarks, holograms or unique serial numbers to track their journey, ensure accountability and to prevent forgery or counterfeiting.