# plus/minus epsilon

Page 4### White-Box Cryptography: Introduction

1 Feb 2016White-Box Cryptography is the study of securing symmetric encryption algorithms
in the *white-box attack context (WBAC)*, where an adversary obtains an
implementation of the algorithm and is allowed to observe/alter every step of
its execution (with instantiated cryptographic keys).

### Cryptographic Data Structures

8 Apr 2015We know that a *data structure* is a particular way of organizing data so that
we can efficiently solve a problem with it. Perhaps a *cryptographic data
structure* would just be the same thing, but with a notion of *security*
determined by an adversary's ability to win a certain game.

In a sense, they're minimal cryptosystems that can be glued together into more complex cryptosystems similar to the way that fundamental data structures can be glued together to give solutions to increasingly complicated problems.

### Google's Macaroons in Five Minutes or Less

5 Dec 2014*Macaroons* are a proposed method of distributed (NOT decentralized)
authorization. Their main distinction from a bearer token is that, if I'm given
a Macaroon that authorizes me to perform some action(s) under certain
restrictions, I can non-interactively build a second Macaroon with stricter
restrictions that I can then give to you. For example, if I have a Macaroon
that allows me to `view`

and `delete`

an image on , I
can construct a second Macaroon that only allows the holder to `view`

the image
as long as `time`

≤ `"5/1/13, 1am GMT"`

and give that to all of my friends.

### A Small SRP Protocol for Web Applications

30 Nov 2014*Purpose:*To present a more efficient authentication scheme, geared towards web applications served over TLS or another secure channel.*Audience:*Web application designers interested in security.*Implementation:*

### A Criticism of JavaScript Cryptography

17 Jun 2014To be pedantic, perhaps a better name for this post would be "A Criticism of In-Browser Cryptography," because it's really the "In-Browser" part that gets people--JavaScript is just another programming language.

### One-Time Attribute-Based Signatures

30 May 2014A *One-Time Attribute-Based Signature* scheme allows a signer, who posses a
set of attributes verified by an authority, to sign a message with a predicate
that is satisfied by his attributes. The signature can reveal no more about the
signer than the predicate requires, and it should be infeasible to link multiple
signatures to the same signer (signatures should be *anonymous*). Multiple
users, each with only a *strict subset* of the required attributes to satisfy a
predicate, should *not* be able to collude and forge a signature that
*does satisfy* the predicate (the scheme should be *collusion-resistant*).

### Optimizing SEAD for Secure Distributed Hash Tables

16 Apr 2014SEAD, the Secure Efficient Ad hoc Distance vector routing protocol, is a recent
secure ad-hoc routing protocol designed to use *symmetric* cryptographic
primitives almost exclusively. Relying on symmetric cryptography, rather than
*asymmetric* often requires 3 to 4 orders of magnitude less computation with a
negligible increase in storage or network overhead.

### A Generalization of Secure Distributed Hash Tables

27 Mar 2014Peer-to-peer distributed hash tables have been the subject of a large amount of
research because they solve a significant problem in computer science:
the *secure* and *efficient* distribution of large amounts of data amongst a
loose collection of disparate nodes, lacking any centralized authorities or
hierarchies.