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The advantage of a digital press is that in a single pass through the printer a void pantograph with all the variable data can be printed on plain paper. Copy-evident paper, sometimes marketed as ‘security paper’, is pre-printed void pantograph paper that was usually produced on an offset or flexographic press. The quality of the void ...
Yellow dots on white paper, produced by color laser printer (enlarged, dot diameter about 0.1 mm) Printer tracking dots, also known as printer steganography, DocuColor tracking dots, yellow dots, secret dots, or a machine identification code (MIC), is a digital watermark which many color laser printers and photocopiers produce on every printed page that identifies the specific device that was ...
Letterlocking is the act of folding and securing a written message (such as a letter) on papyrus, parchment, or paper, without requiring it to be contained in an envelope or packet. It is a traditional method of document security that utilizes folding and cutting. [ 1 ]
Barack Obama's birth certificate on security paper.. Security paper is a paper used in security printing that incorporates features that can be used to identify or authenticate a document as original, e.g., watermarks or invisible fibres in paper, or features that demonstrate tamper evidence when fraud is attempted, e.g., to remove or alter print such as amounts or signatures on a cheque.
Visual cryptography is a cryptographic technique which allows visual information (pictures, text, etc.) to be encrypted in such a way that the decrypted information appears as a visual image. One of the best-known techniques has been credited to Moni Naor and Adi Shamir , who developed it in 1994. [ 1 ]
Encryption scrambles and unscrambles your data to keep it protected. • A public key scrambles the data. • A private key unscrambles the data. Credit card security. When you make a purchase on AOL, we'll only finish the transaction if your browser supports SSL.
• Regularly scan your computer for spyware and viruses using anti-virus software. If you don’t have a one, we recommend McAfee Internet Security Suite – Special edition from AOL. • Update your Windows or Mac OS operating system to repair necessary programs, hardware and devices. Enabling automatic updates on your computer will do this ...
Polygraphic substitution cipher: the unit of substitution is a sequence of two or more letters rather than just one (e.g., Playfair cipher) Transposition cipher: the ciphertext is a permutation of the plaintext (e.g., rail fence cipher) Historical ciphers are not generally used as a standalone encryption technique because they are quite easy to ...