scholarly journals On the Security of Smartphone Unlock PINs

2021 ◽  
Vol 24 (4) ◽  
pp. 1-36
Author(s):  
Philipp Markert ◽  
Daniel V. Bailey ◽  
Maximilian Golla ◽  
Markus Dürmuth ◽  
Adam J. Aviv
Keyword(s):  
Security Level ◽  
First Choice ◽  
User Frustration ◽  
Guessing Attack ◽  
Comprehensive Study

In this article, we provide the first comprehensive study of user-chosen four- and six-digit PINs ( n =1705}) collected on smartphones with participants being explicitly primed for device unlocking. We find that against a throttled attacker (with 10, 30, or 100 guesses, matching the smartphone unlock setting), using six-digit PINs instead of four-digit PINs provides little to no increase in security and surprisingly may even decrease security. We also study the effects of blocklists, where a set of “easy to guess” PINs is disallowed during selection. Two such blocklists are in use today by iOS, for four digits (274 PINs) as well as six digits (2,910 PINs). We extracted both blocklists and compared them with six other blocklists, three for each PIN length. In each case, we had a small (four-digit: 27 PINs; six-digit: 29 PINs), a large (four-digit: 2,740 PINs; six-digit: 291,000 PINs), and a placebo blocklist that always excluded the first-choice PIN. For four-digit PINs, we find that the relatively small blocklist in use today by iOS offers little to no benefit against a throttled guessing attack. Security gains are only observed when the blocklist is much larger. In the six-digit case, we were able to reach a similar security level with a smaller blocklist. As the user frustration increases with the blocklists size, developers should employ a blocklist that is as small as possible while ensuring the desired security.Based on our analysis, we recommend that for four-digit PINs a blocklist should contain the 1,000 most popular PINs to provide the best balance between usability and security and for six-digit PINs the 2,000 most popular PINs should be blocked.

Progress In The Practical Application Of Automated Image Analysis To Tem Negatives

1977 ◽  
Vol 35 ◽  
pp. 214-217
Author(s):  
F. A. Heckman ◽  
E. Redman ◽  
J.E. Connolly
Keyword(s):  
Image Analysis ◽  
Image Quality ◽  
Exposure Time ◽  
Image Contrast ◽  
Automated Image Analysis ◽  
Practical Application ◽  
Factors Affecting ◽  
High Image Quality ◽  
Qualitative Evidence ◽  
Comprehensive Study

In our initial publication on this subject1) we reported results demonstrating that contrast is the most important factor in producing the high image quality required for reliable image analysis. We also listed the factors which enhance contrast in order of the experimentally determined magnitude of their effect. The two most powerful factors affecting image contrast attainable with sheet film are beam intensity and KV. At that time we had only qualitative evidence for the ranking of enhancing factors. Later we carried out the densitometric measurements which led to the results outlined below.Meaningful evaluations of the cause-effect relationships among the considerable number of variables in preparing EM negatives depend on doing things in a systematic way, varying only one parameter at a time. Unless otherwise noted, we adhered to the following procedure evolved during our comprehensive study:Philips EM-300; 30μ objective aperature; magnification 7000- 12000X, exposure time 1 second, anti-contamination device operating.

Hexachlorobenzene toxicity in the monkey ovary: III. Ultrastructure induced by high (10 mg/kg) dose exposure

1991 ◽  
Vol 49 ◽  
pp. 130-131
Author(s):  
A. Singh ◽  
A. Dykeman ◽  
J. Jarrelf ◽  
D. C. Villeneuve
Keyword(s):  
Present Report ◽  
Reproductive Toxicity ◽  
Control Group ◽  
Primate Model ◽  
Human Follicular Fluid ◽  
Thin Sections ◽  
Cynomolgus Monkeys ◽  
Cacodylate Buffer ◽  
Induction Cycle ◽  
Comprehensive Study

Hexachlorobenzene (HCB), a persistent and mobile organochlorine pesticide, occurs in environment. HCB has been shown to be present in human follicular fluid. An objective of the present report, which is part of a comprehensive study on reproductive toxicity of HCB, was to determine the cytologic effects of the compound on ovarian follicles in a primate model.Materials and Methods. Eight Cynomolgus monkeys were housed under controlled conditions at Animal facility of Health and Welfare, Ottawa. Animals were orally administered gelatin capsules containing HCB mixed with glucose in daily dosages of 0.0 or 10 mg/kg b.w. for 90 days; the former was the control group. On the menstrual period following completion of dosing, the monkeys underwent an induction cycle of superovulation. At necropsy, one-half of an ovary from each animal was diced into ca. 2- to 3-mm cubed specimens that were fixed by immersion in 2.5% glutaraldehyde in 0.1 M cacodylate buffer (pH 7.3). Subsequent procedures followed to obtain thin sections that were examined in a Hitachi H-7000 electron microscope have been described earlier.

Comparison of Substructures Between Uniaxial and Biaxial Deformation in 1100-0 Aluminum

1981 ◽  
Vol 39 ◽  
pp. 52-53
Author(s):  
D. L. Rohr ◽  
S. S. Hecker
Keyword(s):  
Plastic Strain ◽  
Cell Walls ◽  
Room Temperature ◽  
Mechanical Response ◽  
Biaxial Tension ◽  
Initial Deformation ◽  
Uniaxial Deformation ◽  
Biaxial Deformation ◽  
Stress States ◽  
Comprehensive Study

As part of a comprehensive study of microstructural and mechanical response of metals to uniaxial and biaxial deformations, the development of substructure in 1100 A1 has been studied over a range of plastic strain for two stress states.Specimens of 1100 aluminum annealed at 350 C were tested in uniaxial (UT) and balanced biaxial tension (BBT) at room temperature to different strain levels. The biaxial specimens were produced by the in-plane punch stretching technique. Areas of known strain levels were prepared for TEM by lapping followed by jet electropolishing. All specimens were examined in a JEOL 200B run at 150 and 200 kV within 24 to 36 hours after testing.The development of the substructure with deformation is shown in Fig. 1 for both stress states. Initial deformation produces dislocation tangles, which form cell walls by 10% uniaxial deformation, and start to recover to form subgrains by 25%. The results of several hundred measurements of cell/subgrain sizes by a linear intercept technique are presented in Table I.

Microvasculature and structure of hemal lymph nodes in the wall of the rabbit bladder: a vascular corrosion casting and EM study

1995 ◽  
Vol 53 ◽  
pp. 1074-1075
Author(s):  
F.E. Hossler ◽  
M.I. McKamey ◽  
F.C. Monson
Keyword(s):  
Lymph Nodes ◽  
Light Microscopy ◽  
Corrosion Casting ◽  
Fixed Tissue ◽  
Infusion Pressure ◽  
India Ink ◽  
Cacodylate Buffer ◽  
Rabbit Bladder ◽  
Lateral Walls ◽  
Comprehensive Study

A comprehensive study of the microvasculature of the normal rabbit bladder, revealed unusual "capillary glomeruli" along the lateral walls. Here they are characterized as hemal lymph nodes using light microscopy, SEM, TEM, ink injection, and vascular casting.Bladders were perfused via a cannula placed in the abdominal aorta with either 2% glutaraldehyde in 0.1M cacodylate buffer (pH 7.4) for fixation, 10% India ink in 0.9% saline and 0.1M phosphate (pH 7.4) for vessel tracing, or resin (Mercoximethylmethacrylate: catalyst, 4:1:0.3; Ladd Research Industries) for vascular corrosion casting. Infusion pressure was 100mm Hg. Fixed tissue was sectioned from epon-araldyte resin, and stained with toluidine blue for light microscopy, and lead and uranium for TEM. Ink injected tissue was photographed directly from saline-filled bladders illuminated from below. Resin-filled tissue was macerated in 5% KOH and distilled water. Casts were critical point dried, sputter coated with goldpalladium, and examined by routine SEM at 10 KV.

β-Blockers Not First Choice in Primary HT

2006 ◽  
Vol 39 (4) ◽  
pp. 55
Author(s):  
ROBERT FINN
Keyword(s):  
First Choice ◽  
Β Blockers

Nonsurgical Therapies for Hepatocellular and Cholangiocellular Carcinoma

Swiss Surgery ◽  
1999 ◽  
Vol 5 (3) ◽  
pp. 116-121 ◽  
Author(s):  
Schmassmann
Keyword(s):  
Current Trend ◽  
Percutaneous Ethanol Injection ◽  
Cholangiocellular Carcinoma ◽  
Multidisciplinary Therapy ◽  
Term Survival ◽  
Ethanol Injection ◽  
First Choice ◽  
Tumor Stages ◽  
Choice Of Treatment ◽  
Advanced Stages

Surgical resection is the first choice of treatment for patients with hepatocellular (HCC) and cholangiocellular carcinomas. Prolongation of survival is, however, the only realistic goal for most patients, which can be often achieved by nonsurgical therapies. Inoperable patients with large or multiple HCCs are usually treated with transarterial chemoembolization (TACE) with lipiodol in combination with a chemotherapeutic drug and gelfoam. Three-year survival depends on the stage of the disease and is about 20%. Patients with earlier tumor stages (one or two tumor nodules less than 3cm in size) are suitable for treatment with percutaneous ethanol injection (PEI) alone or in combination with TACE. Several studies have shown that in these early stages, the 3-year survival rate is approximately 55%-70% in the actively treated patients which is significantly higher than in untreated patients. In advanced stages of the disease, TACE and PEI have no effect on survival and should not be performed. Some of these patients have been successfully treated with octreotide. Patients with inoperable cholangiocellular carcinoma are treated by endoscopic or percutaneous stent placement. If stenting does not achieve adequate biliary drainage, multidisciplinary therapy including internal / external radiotherapy or photodynamic therapy should be considered in patients with potential long-term survival. In conclusion, nonresectional therapies play an essential role in the therapy of inoperable hepato- and cholangiocellular carcinomas as they lead to satisfactory survival. Multidisciplinary therapy appears to be the current trend of management.

Surgery of ulcus cruris venosum

Phlebologie ◽  
2010 ◽  
Vol 39 (03) ◽  
pp. 156-162 ◽  
Author(s):  
C. Schwahn-Schreiber
Keyword(s):  
Subcutaneous Tissue ◽  
Ulcus Cruris ◽  
Healing Time ◽  
Ulcus Cruris Venosum ◽  
Venous Stasis ◽  
Morphological Alterations ◽  
First Choice ◽  
Choice Of Treatment ◽  
Chronic Compartment Syndrome ◽  
Shave Therapy

SummaryAdvanced chronic venous stasis syndrome is characterized by irreversible and self-perpetuating morphological alterations in the lower leg. A chronic inflammatory process results in sclerosis, which progresses from the skin to the subcutaneous tissue and ultimately the fascia, sometimes including muscle and ankle joint and leading to chronic compartment syndrome. To cure these severe alterations with non healing ulcers decompression of the compartments like paratibial fasciotomy with SEPS and crural fasciectomy or removal of sclerosis like shave therapy are successful surgical procedures. Indication should be adapted to the extension of ulcer. Indications of the operations and the techniques are described, complications and results are discussed. Due to ulcer extension especially shave therapy (removal of the sclerotic tissue epifascial) and crural fasciectomy (removal of sclerosis including fascia) are very successful with up to 80% healing rate, even in severe cases and even after long term (up to 8 years). Since shave therapy is easy, short and simple with short healing time, few complications and good aesthetical result it is the first choice of treatment for non healing leg ulcers. Fasci ectomy is reserved for special indications such as deep transfascial necrosis or failure of shave therapy.

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