glusk / srp6-variables Goto Github PK

The two parties also employ the following safeguards:

1. The user will abort if he receives B == 0 (mod N) or u == 0.
2. The host will abort if it detects that A == 0 (mod N).

From: http://srp.stanford.edu/design.html

Lets add the following:

• Travis build status
• Codacy project report
• Coveralls coverage
• LoC + HoC

The above mentioned project implements some version of SRP-6. Lets add its test vectors!

Project's Wiki

Tool used to generate Test Vectors: mysrp.py

Also take note of the checks in #28.

Improve this coverage:

https://coveralls.io/builds/35917780

Add WoW authentication SRP-6 test vectors, dumped from a private server session.

Implement:

• u Random scrambling parameter -- #16
• A,B Public ephemeral values -- #22 #24
• a,b Private ephemeral values -- #26
• x Private key (derived from p and s) -- #12
• v Password verifier -- #9
• k Multiplier parameter (k = H(N, g) in SRP-6a, k = 3 for legacy SRP-6) -- #30

• M1,M2 Proofs of session key -- #49 #43
• S Shared secret -- #35 #37
• K Session key -- #41

• Basic usage README section with code examples -- #52

It's not really clear what the -1 is for in the following snippet:

new SRP6RandomEphemeral(rng, -1, N);

Let's document that in the SRP6RandomEphemeral constructor.

Also take note of the checks in #28

Add an interface that will represent SRP-6 variables and a default implementation.

After we implement #77, this should be much easier.

https://en.wikipedia.org/wiki/Secure_Remote_Password_protocol#Example_code_in_Python

State that the exception is thrown when trying to cut off byte sequences, representing numbers, to a shorter length instead of zero-padding them to longer ones.

Provide an example.

Correct the description:

• improve grammar
• mention Caesar

Corrections for #18.

Library should at least log whenever a user is using too short, and thus cryptographically-unsafe, variables.

Limits:

• a, b:

  The private values a and b SHOULD be at least 256-bit random numbers, ... [RFC 5054]

Let's try to add repoToken to the configuration file.

Rename base interface that was added in #3.

We want something like this:

// SRP6IntegerVariable x = ...
// SRP6IntegerVariable y = ...

// bytes of x in BIG_ENDIAN byte order
Bytes b1 = new SRP6IntegerVariableBytes(x, ByteOrder.BIG_ENDIAN);
// bytes of x in BIG_ENDIAN byte order, zero-padded to the byte length of y
Bytes b2 = new SRP6IntegerVariableBytes(x, ByteOrder.BIG_ENDIAN, y);

instead of in addtion to this:

// SRP6IntegerVariable x = ...
Bytes b1 = x.bytes(ByteOrder.BIG_ENDIAN);
Bytes b1 = x.bytes(ByteOrder.BIG_ENDIAN, 32);

in order to enhance object composition and defer execution.

Some of the existing open source SRP-6 Java libraries include:

• Randgalt/srpforjava
• Bouncy Castle Provider
  
  • org.bouncycastle.tls.crypto.impl.jcajce.srp
• Nimbus SRP6a
• SRP6 for C# and Java
• GNU Crypto
  • gnu.crypto.key.srp6

What I've found is that such libraries are not easy to extend.

Most of them work only with big-endian byte array representations and some of them aren't compliant with RFC 5054.

With that in mind, I decided to create a library of basic building blocks (SRP-6 Variables) that one can use to implement the protocol.

Zero-padd Public Keys (A, B) to the byte length of Nt:

u = H(PAD(A) | PAD(B))

Currently, we have the following conde snippet as part of our README.md:

if (!(cM2.equals(M2))) {
    throw new SRP6Exception("Server proof mismatch!");
}

This is not an exceptional behaviour. It's perfectly normal that an SRP6 authentication fails (ie, wong credentials). Let's not use exceptions for flow control in our examples. Fix the example; re-think where to throw an exception and what type.

Should be done after/with #78.

• check if a variable is a safe prime of the form: p = 2q + 1, where p and q are prime numbers
• check if a variable is generator or a primitive root modulo N

Let's do the same as here: Glusk/caesar#67.

The method equals() in SRP6IntegerVariable should have a different signature. See also: Java8: Why is it forbidden to define a default method for a method from java.lang.Object.

Lets do something similar as here: Glusk/caesar#59

SRP6RandomEphemeral was first implemented as part of #26.

Remove synchronized from method declaration. In project Loom, a synchronized block or a method blocks the underlying platform thread. Assuming SRP6 authentication runs in a virtual thread, this could potentially slow the application.

Fix the typo in the code comment.

• SRP6Exception extends Exception
  • SRP6PaddingException
  • SRP6SecurityException