2026 Begin RSA Private Key 4 End RSA Private Key Shirt

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$19.95

Size Guide

Size Guide & Product Details

These charts show garment measurements taken with the item laid flat. Width refers to the distance across the front, not the measurement around the body. Centimeter values are calculated from inches and rounded to one decimal place. Match the chart to the product code you select, as available sizes may differ by color.
SIZE WIDTH LENGTH
S 18 in 28 in
M 20 in 29 in
L 22 in 30 in
XL 24 in 31 in
2XL 26 in 32 in
3XL 28 in 33 in
4XL 30 in 34 in
5XL 32 in 35 in
SIZE WIDTH LENGTH
S 45.7 cm 71.1 cm
M 50.8 cm 73.7 cm
L 55.9 cm 76.2 cm
XL 61.0 cm 78.7 cm
2XL 66.0 cm 81.3 cm
3XL 71.1 cm 83.8 cm
4XL 76.2 cm 86.4 cm
5XL 81.3 cm 88.9 cm

Fabric & Construction

  • Fabric weight is 5.3 oz.
  • Solid shades use 100% cotton. Ash Grey contains 99% cotton and 1% polyester; Sport Grey contains 90% cotton and 10% polyester; Dark Heather contains equal parts cotton and polyester.
  • A classic unisex shape is finished with reinforced seams at the neck and shoulders, plus a removable label.
  • Some colors are available in 6XL. That size is omitted from this chart because the published length measurement is inconsistent.
  • The design is printed using DIGISOFT®.
SIZE WIDTH LENGTH
S 17.25 in 25.5 in
M 19.25 in 26 in
L 21.25 in 27 in
XL 23.25 in 28 in
2XL 25.25 in 28.5 in
3XL 27.25 in 29 in
SIZE WIDTH LENGTH
S 43.8 cm 64.8 cm
M 48.9 cm 66.0 cm
L 54.0 cm 68.6 cm
XL 59.1 cm 71.1 cm
2XL 64.1 cm 72.4 cm
3XL 69.2 cm 73.7 cm

Material & Fit

  • Constructed from preshrunk cotton, with blends that vary by shade: Ash Grey is 99% cotton and 1% polyester; Sport Grey is 90% cotton and 10% polyester; Dark Heather and Graphite Heather are 50% cotton and 50% polyester.
  • Side seams create a gently tapered fit beneath a scoop neckline.
  • A seamless ribbed neckline and double-needle stitching complete the construction.
  • Artwork is applied with DIGISOFT® printing.
SIZE WIDTH LENGTH
S 20 in 26 in
M 22 in 27 in
L 24 in 28 in
XL 26 in 29 in
2XL 28 in 30 in
3XL 30 in 31 in
4XL 32 in 32 in
5XL 34 in 33 in
SIZE WIDTH LENGTH
S 50.8 cm 66.0 cm
M 55.9 cm 68.6 cm
L 61.0 cm 71.1 cm
XL 66.0 cm 73.7 cm
2XL 71.1 cm 76.2 cm
3XL 76.2 cm 78.7 cm
4XL 81.3 cm 81.3 cm
5XL 86.4 cm 83.8 cm

Fleece Details & Care

  • The fabric weighs 8 oz. CustomCat’s listed composition is 55% cotton and 45% polyester.
  • Air-jet yarn adds softness to the fleece surface.
  • The ribbed waistband and cuffs contain spandex, while the seams feature double-needle stitching.
  • Machine wash in cold water and use a low tumble-dry setting.
  • Print application: DIGISOFT®.
SIZE WIDTH LENGTH
S 20 in 27 in
M 22 in 28 in
L 24 in 29 in
XL 26 in 30 in
2XL 28 in 31 in
3XL 30 in 32 in
4XL 32 in 33 in
5XL 34 in 34 in
SIZE WIDTH LENGTH
S 50.8 cm 68.6 cm
M 55.9 cm 71.1 cm
L 61.0 cm 73.7 cm
XL 66.0 cm 76.2 cm
2XL 71.1 cm 78.7 cm
3XL 76.2 cm 81.3 cm
4XL 81.3 cm 83.8 cm
5XL 86.4 cm 86.4 cm

Hoodie Features

  • Made with 8 oz. fabric; CustomCat lists a blend of 55% cotton and 45% polyester.
  • This unisex pullover includes a front pouch pocket and double-needle stitching.
  • Air-jet yarn provides a smoother surface and helps minimize pilling.
  • Wash cold in the machine, then tumble dry on low.
  • DIGISOFT® is used to print the design.
SIZE WIDTH LENGTH
S 18 in 28 in
M 20 in 29 in
L 22 in 30 in
XL 24 in 31 in
2XL 26 in 32 in
3XL 28 in 33 in
SIZE WIDTH LENGTH
S 45.7 cm 71.1 cm
M 50.8 cm 73.7 cm
L 55.9 cm 76.2 cm
XL 61.0 cm 78.7 cm
2XL 66.0 cm 81.3 cm
3XL 71.1 cm 83.8 cm

Long-Sleeve Construction

  • Preshrunk cotton jersey with a fabric weight of 5.3 oz. Sport Grey uses 90% cotton and 10% polyester.
  • The seamless 7/8-inch collar is finished with double-needle stitching.
  • Neck and shoulder seams are reinforced, and the bottom hem is double-needle stitched.
  • The listed size range runs from S to 3XL.
  • Printing technology: DIGISOFT®.
SIZE WIDTH LENGTH
YXS 16 in 20.5 in
YS 17 in 22 in
YM 18 in 23.5 in
YL 19 in 25 in
YXL 20 in 26.5 in
SIZE WIDTH LENGTH
YXS 40.6 cm 52.1 cm
YS 43.2 cm 55.9 cm
YM 45.7 cm 59.7 cm
YL 48.3 cm 63.5 cm
YXL 50.8 cm 67.3 cm

Youth Tee Details

  • The 5.3 oz. fabric is 100% cotton in solid colors.
  • Ash is 99% cotton and 1% polyester; Sport Grey is 90% cotton and 10% polyester; Dark Heather is a 50/50 cotton-polyester blend.
  • Features include a seamless 3/4-inch collar with double-needle stitching, reinforced shoulder seams, and a removable label.
  • The printed artwork uses DIGISOFT®.
SIZE WIDTH LENGTH
XS 16.25 in 26 in
S 18.25 in 27 in
M 20.25 in 28 in
L 22.25 in 29 in
XL 24.25 in 30 in
2XL 26.25 in 31 in
SIZE WIDTH LENGTH
XS 41.3 cm 66.0 cm
S 46.4 cm 68.6 cm
M 51.4 cm 71.1 cm
L 56.5 cm 73.7 cm
XL 61.6 cm 76.2 cm
2XL 66.7 cm 78.7 cm

Tank Fabric & Fit

  • Bella + Canvas 3480 is a unisex jersey tank built with side seams.
  • The standard 4.2 oz. fabric is 100% combed ring-spun cotton.
  • Athletic Heather contains 90% cotton and 10% polyester. Dark Grey Heather contains 52% cotton and 48% polyester.
  • Triblend shades use 3.8 oz. fabric comprising 50% polyester, 25% cotton, and 25% rayon.
  • The listed sizes extend from XS through 2XL.
  • Decoration is applied using DIGISOFT® printing.
SIZE WIDTH LENGTH
XS 15.25 in 18.25 in
S 15.875 in 19.25 in
M 16.5 in 19.75 in
L 17.375 in 20.375 in
XL 18.25 in 21 in
2XL 19.125 in 21.625 in
SIZE WIDTH LENGTH
XS 38.7 cm 46.4 cm
S 40.3 cm 48.9 cm
M 41.9 cm 50.2 cm
L 44.1 cm 51.8 cm
XL 46.4 cm 53.3 cm
2XL 48.6 cm 54.9 cm

Fabric, Shape & Sizing

  • Fabric weight is 3.7 oz. Standard colors contain 65% polyester and 35% viscose.
  • Athletic Heather uses 52% polyester and 48% viscose.
  • The draped fit is complemented by a round neckline and racerback styling.
  • CustomCat notes that this style runs small and suggests going up one size for a fuller fit.
  • Front length is taken from the lowest point of the neckline down to the bottom seam.
  • Print process: DIGISOFT®.
SIZE WIDTH LENGTH
YS 17 in 21.25 in
YM 18 in 22.5 in
YL 19 in 24 in
YXL 20 in 25.5 in
SIZE WIDTH LENGTH
YS 43.2 cm 54.0 cm
YM 45.7 cm 57.2 cm
YL 48.3 cm 61.0 cm
YXL 50.8 cm 64.8 cm

Youth Hoodie Information

  • Made with 7.75 oz. fabric containing equal proportions of cotton and polyester.
  • The youth hoodie is designed without a drawcord.
  • For a fuller fit, CustomCat suggests choosing one or two sizes larger. Compare the garment dimensions before deciding.
  • Artwork printing is handled with DIGISOFT®.
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2026 Begin RSA Private Key 4 End RSA Private Key Shirt takes a familiar piece of computer security formatting and turns it into a minimalist programming joke. Built around the recognizable structure of an RSA private key, this graphic tee replaces complicated encrypted-looking information with a single, unexpected number. The result is a clever take on cryptography, coding culture and the humor of making something technically complex look ridiculously simple. Its message comes from computer science rather than a specific public event.

2026 Begin RSA Private Key 4 End RSA Private Key Shirt – A Cryptography Joke Hidden in Plain Sight

The Begin RSA Private Key 4 End RSA Private Key Shirt features black monospaced lettering arranged in three lines across the upper chest, resembling the contents of a computer security file. Its minimalist graphic recreates the familiar opening and closing markers of an RSA private key, with the number “4” standing alone between them.
The printed design reads: “ —–BEGIN RSA PRIVATE KEY—–/ 4 /—–END RSA PRIVATE KEY—–“
The first line introduces the private key using uppercase letters and five hyphens on either side. The middle line contains only the number “4” positioned toward the left edge of the text block. The final line repeats the structure with “END” replacing “BEGIN” completing the familiar computer-file layout.
The design uses a simple black-and-white color combination without illustrations, decorative graphics or additional symbols. Its typewriter-inspired lettering gives the print the appearance of technical text copied directly from a terminal or configuration file.
What makes this white programming T-shirt distinctive is its deliberately understated presentation. At first glance, the text resembles an ordinary snippet of cryptographic information. A closer look reveals the punchline: a supposedly important private key reduced to one character. The contrast between serious security terminology and the unexpectedly simple content creates the joke without requiring an explanation printed on the garment.
2026 Begin RSA Private Key 4 End RSA Private Key Shirt
2026 Begin RSA Private Key 4 End RSA Private Key Shirt
The shirt‘s phrase references the text format commonly used to store RSA private keys. RSA is a public-key cryptography system and private keys can be represented using PEM encoding which places encoded key information between recognizable beginning and ending markers.
In a normal RSA private key file, the content between those markers consists of encoded data representing the key’s mathematical components. The format is documented in RFC 7468, published in April 2015 and appears in cryptography tools and developer documentation.
The shirt replaces that complex content with the number “4“. This is the central joke: something associated with sophisticated encryption is presented as though its entire secret could fit into a single digit. It is a playful exaggeration, not a functional RSA private key.
The design turns a recognizable technical convention into deadpan computer humor, fitting naturally within the broader world of graphic T-shirts.
Product Details
Style: Short-sleeve crew-neck T-shirt, shown in white
Design: Printed black monospaced text on the front
Size: See size chart
Construction: Ribbed crew neckline, short sleeves, straight bottom hem
Fit: Straight-cut silhouette
Care Instructions
Machine wash cold with similar colors.
Turn inside out before washing.
Use a gentle wash cycle.
Avoid bleach and harsh cleaning products.
Tumble dry low or hang to dry; iron inside out if needed.

Shipping & Returns

Shipping

  • United States: flat $6.95 per order, delivered in 5–10 business days after production.
  • International (Canada, UK, Australia and most of Europe): flat $14.00 per order, delivered in 8–15 business days after production.
  • Production: 3–5 business days for tees, hoodies, sweatshirts and hats; 5–7 business days for all over print styles.
  • Every order ships with tracking. See our full Shipping Policy.

Returns & Refunds

  • Return eligible items within 30 days of delivery (unworn, unwashed, original condition).
  • Damaged, defective or wrong item? Email photos within 7 days of delivery for a free replacement or full refund.
  • Approved refunds are issued to your original payment method within 7 business days. See our Return & Refunds Policy.

Cancellations

Cancel or change your order within 6 hours of purchase for a full refund. See our Cancellation & Modification Policy.

Questions? Email [email protected] (Mon–Fri, 8 AM–5 PM ET).