Laser PIN Letters and Password Security Letters

Laser PIN Letters and Password Letters Made Simple and Secure

Download PCF Laser PIN and Password Security Letters Datasheet


Traditional means of delivering confidential PIN data have relied on impact printing technologies used with multiple carbonless transfer papers collated into a sealed mailer. With laser print technology replacing most computer impact printing, PCF's Laser PIN and Password Letters provide improved levels of document security and quality with real improvements in document processing. PCF's Laser PIN and Password Letters allow the laser printing of confidential data onto a single sheet of paper that can easily be mailed without extra processing.

How PCF's Laser PIN Letters and Password Letters are Used

The key to the security system is the use of a specially designed Laser PIN label which is adhered to the A4 (usual size) paper used for the PIN data printing. This label is pre-constructed from a polyester film using a patented security document system. This system allows specifically printed hidden security messages to be incorporated within separate layers of pigmented and clear polymer coatings.

The Laser PIN letter can then be laser printed with the variable data required in one printing pass. Details such as the recipient's name and address, an introductory letter and the confidential PIN data are all added in this one laser print operation. Many different totally standard laser printers can be used.

The secure data PIN elements are printed onto the Reduced Particle Matt surface of the Laser PIN label but obscured by a random black pattern of dots laid beneath its surface.

Extra security for this printing is achieved when the secure PIN data is printed using a specially designed security font provided by PCF for this secure printing operation. These fonts include built in half tones to specific percentages that allow the laser printed PIN image to be completely obscured.

The remainder of the data, including the recipient's name and address information, will be completely visible on the remaining parts of the document.

Fig 1. This shows an unopened Laser PIN label applied to its paper carrier. The label has been printed with the PIN number, which cannot be viewed in the labels unopened state as it is obscured by the high density Black Security Background.
Fig. 2 This shows the label as it is partially 'opened'. The PIN data becomes visible and the tamper evident security message appears around the edges of the PIN data printed on the film. This feature is achieved using a patented system.
Fig. 3 This shows the label with the film fully detached. The PIN data becomes fully visible on the film slip and the tamper evident security message appearing round the edges of the PIN details fully exposed. This leaves the balance of the label image remaining on the original paper surface.
Fig. 4 This shows the label as it appears when fully RECONSTRUCTED. You will notice that the PIN data is legible, as is the security message. The overall image of the label has become virtually opaque.

PCF's Laser PIN and Password Letters have been designed to allow the complete separation of the PIN number from the recipient's name and address that is remaining on the carrier letter, since this provides better security when the letter is disposed of by the recipient. However the PIN number slip can be designed to remain firmly attached to the letter after reading, with a 'hinge' at either the left or right side of the label.

PCF Laser PIN Letter and Password Letter Testing Summary

At present there are no set rules to test the performance of laser PIN letters, so listed here are the range of tests that have been carried out on PCF's Laser PIN and Password Letters.

Refractive Lighting

A common failure of other laser PIN letters can be very apparent even before any attempt at opening has been made. This is a very simple test and involves holding the PIN data section of the letter at an angle against a bright light source. All too often it is possible to read the secure PIN data because the laser toner coating is too reflective. The PCF PIN label has a 'reduced particle' matt coating which prevents this simple security compromise by eliminating excessive reflectance on the film surface.


PCF's Laser PIN label is produced using fully cured and cross-linked polymer chains within the graphics and the adhesives. Any attempts of reconstruction after pealing off the film for un-authorised PIN access using clear water, latex or solvent based adhesives will not work for long, if at all, as they will not form any part of the cured polymer links.

Complete Label (backlit) Reconstructed Label

This is a simple test that involves viewing the face of the label under magnification. Where data has been printed at 300DPI it is simply a method of following the outline of the laser printed pixels to pick out the image. By in large this is much easier when the scrambling pattern has lost its blackness due to the opacity of the laser coating and starts to appear as a grey colour. PCF Laser PIN and Password Letters carry the most DENSE BLACK image of any laser printable PIN product currently available, but we still highly recommend always using the special security fonts PCF provides and printing at 600 DPI.

Image Quality Testing

When laser printing onto film, the image formed by the toner will always 'sit-up' on the face of the film. This can make the image legible when printed in solid or high percentage half tones. This then can produce a dilemma between security and legibility. The PCF Laser PIN and Password Letter fonts offer the best of both worlds by using relatively small levels of toner with acceptable readability of the PIN.

These photographs of the PCF Laser PIN labels have not been re-touched. It is clear that the PIN can easily be read when the special PCF fonts are used.

Other Tests Carried Out
  • The effect of temperature. Using heat (hot air, steam, micro wave oven) and using cold (Freon gas) to temporarily neutralise adhesives used within the label construction. Through the tamper evident features the labels still showed they had been opened even at these 'nonstandard' temperatures.
  • Thermal transfer using an iron to transfer the toner from the face of the film to paper placed above it, what toner that was removed did not re-create a readable PIN.
  • Various adhesive tapes with various types of adhesive were applied to the Laser PIN label to 'pick off' the toner. The adhesion of the toner to the PIN label and the special fonts were found to make the small amounts of toner lifted off not to produce a legible and un-authorised read of the PIN.
  • The application of solvents, alcohol and petrochemicals also did not produce any readable PIN details or suppress the tamper evident features.
  • High resolution scanning was also tried, and again did not allow the PIN to be read.

Key Benefits from PCF's Laser PIN and Password Letters

  • Original Print quality for the PIN number, no fuzzy carbon copy image to read.
  • Large font size can be used to aid PIN number readability by poor sighted recipients.
  • Multi-level 'tamper evidence' to discourage potential unauthorised PIN number reading.
  • Fully tested to protect recipients from many different types of overt fraud attempts.
  • Access by rightful recipient is simple, easy to understand without instructions, and quick.
  • Simple validation instructions positioned by the side of the Laser PIN label allow easy confirmation that PIN has not been tampered with.
  • The secure PIN data is left separate from the recipient letter leaving no potential linkage when the letter is disposed of.
  • No special equipment is required to laser print and process the Laser PIN Letter.
  • Postal cost savings available from mailing these lighter and less complex documents.
  • Simple 'base stock' can be converted during the laser data print process into any type of PIN letter required with the various versions being controlled at the laser data print stage.
  • Confidentiality is maintained during the data printing process since the laser printer operators are unable to read the PIN on the documents they are printing.

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