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2016-12-19

JSON Web Tokens (JWT)

JSON Web Token (JWT) is an open standard (RFC 7519) that defines a compact and self-contained way for securely transmitting information between parties as a JSON object. This information can be verified and trusted because it is digitally signed. JWTs can be signed using a secret (with the HMAC algorithm) or a public/private key pair using RSA or ECDSA.

They can be used for:

  • Authentication: including a JWT to any HTTP request allows Single Sign On user validation across different domains;
  • Secure Information Exchange: a small amount of data can be stored in the JWT payload, and is digitally signed to ensure its provenance and integrity.

See http://jwt.io for an introduction to JSON Web Tokens.

Our mORMot framework now implements JWT:

  • HS256 (HMAC-SHA256) and ES256 (256-bit ECDSA) algorithms (with the addition of the "none" weak algo);
  • Validates all claims (validation dates, audiences, JWT ID);
  • Thread-safe and high performance (2 µs for a HS256 verification under x64), with optional in-memory cache if needed (e.g. for slower ES256);
  • Stand-alone and cross-platform code (no external dll, works with Delphi or FPC);
  • Enhanced security and strong design - per instance, it is by design immune from https://auth0.com/blog/2015/03/31/critical-vulnerabilities-in-json-web-token-libraries
  • Full integration with the framework.

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2016-11-10

EKON20 mORMot Conferences

EKON20 is now over, and there was a lot of people, great speakers, beautiful T-Shirt, and fresh beer! I've published the slides of my mORMot conferences on SlideShare... EKON20 From RAD to SOA with mORMot EKON20 mORMot Legacy Code Technical Debt Delphi Conference EKON20 Ride a mORMot EKON20 2016  […]

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2016-10-18

Cheat Mode for Private Keys

In order to follow best practice, our .private key files are always protected by a password.  A random value with enough length and entropy is always proposed by the ECC tool when a key pair is generated, and could be used directly.
It is always preferred to trust a computer to create true randomness (and SynCrypto.pas's secure TAESPRNG was designed to be the best possible seed, using hardware entropy if available), than using our human brain, which could be defeated by dictionary-based password attacks.
Brute force cracking would be almost impossible, since PBKDF2_HMAC_SHA256 Password-Based Key Derivation Function with 60,000 rounds is used, so rainbow tables (i.e. pre-computed passwords list) will be inoperative, and each password trial would take more time than with a regular Key Derivation Function.

The issue with strong passwords is that they are difficult to remember. If you use not pure random passwords, but some easier to remember values with good entropy, you may try some tools like https://xkpasswd.net/s which returns values like $$19*wrong*DRIVE*read*61$$.
But even then, you will be able to remember only a dozen of such passwords. In a typical public key infrastructure, you may create hundredths of keys, so remembering all passwords is no option for an average human being as (you and) me.

At the end, you end up with using a tool to store all your passwords (last trend is to use an online service with browser integration), or - admit it - store them in an Excel document protected by a password. Most IT people - and even security specialists - end with using such a mean of storage, just because they need it.
The weaknesses of such solutions can be listed:

  • How could we trust closed source software and third-party online services?
  • Even open source like http://keepass.info/help/base/security.html may appear weak (no PBKDF, no AFSplit, managed C#, SHA as PRNG);
  • The storage is as safe as the "master password" is safe;
  • If the "master password" is compromised, all your passwords are published;
  • You need to know the master password to add a new item to the store.

The ECC tool is able to work in "cheat mode", storing all .private key files generated passwords in an associated .cheat local file, encrypted using a cheat.public key.

As a result:

  • Each key pair will have its own associated .cheat file, so you only unleash one key at a time;
  • The .cheat file content is meaningless without the cheat.private key and its master password, so you can manage and store them together with your .private files;
  • Only the cheat.public key is needed when creating a key pair, so you won't leak your master password, and even could generate keys in an automated way, on a distant server;
  • The cheat.private key will be safely stored in a separated place, only needed when you need to recover a password;
  • It uses strong File Encryption, with proven PBKDF, AFSplit, AES-PRNG, and ECDH/ECIES algorithms.

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2016-09-24

Public-key Asymmetric Cryptography via SynECC

After weeks of implementation and testing, we introduce today a new feature of our mORMot Open-Source Framework.

Asymmetric encryption, also known as public-key cryptography, uses pairs of keys:

  • Public keys that may be disseminated widely;
  • Paired with private keys which are known only to the owner.

The framework SynEcc unit features a full asymmetric encryption system, based on Elliptic curve cryptography (ECC), which may be used at application level (i.e. to protect your application data, by signing or encrypting it), or at transmission level (to enhance communication safety).
A full set of high-level features, including certificates and command line tool, offers a stand-alone but complete public-key infrastructure (PKI).

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2016-09-06

Ride the mORMot at EKON 20 in Dusseldorf!

There are still a few days for "very early birds" offer for EKON 20 conference, and meet us for 3 sessions (including a half-day training/introduction to mORMot)! Join us the 7-9th of November in Düsseldorf! Our sessions are not restricted to mORMot, but will use mORMot to illustrate some  […]

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2016-07-30

Bloom Filter and Big Data

Especially if you are dealing with a lot of data, you often need a way to identify if a value is available in a value set.
A typical use case is if you have data sharded among several nodes, and you want to avoid asking each node for each incoming request.

A naive approach could be to store all data in a memory list.
But here we are really talking about a lot of data, and it would simply not fit into a memory list.

We may say that it is the purpose of a database to maintain such a list.
So you start a good CREATE TABLE on your RDBMS with a single indexed primary key column, fill it with your data, and run a proper SELECT.
But it takes a lot of storage, insertion is slow, and this database becomes a bottleneck.

Then you consider using some NoSQL database like Redis.
It is faster than a RDBMS, but it tends to use a lot of memory, and it is still resource consuming to update the values.

No comes Bloom Filter magic.
It allows to store the presence of high-number of values with a small memory space, with a predefined ratio of potential false positives.

We just introduced a TSynBloomFilter class in our Open Source mORMot framework trunk, which features an optimized and self-tuning Bloom Filter storage, with potential low-bandwidth synchronization over the wire.

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2016-05-30

SOA and stub/mock working on Linux x86, x64, arm32 and aarch64

Some patches, provided by ALFred, did introduce some new platforms under Linux: Linux x86 (aka Intel 32-bit) Linux x64 (aka Intel 64-bit) Linux AARCH32 (aka ARM 32-bit) Linux AARCH64 (aka ARM 64-bit) It needs the latest trunk version of the FPC compiler, and the "Interface Enhanced RTTI"  […]

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2016-05-14

Anti-forensic, safe storage of private keys

In any modern application, especially on Client/Server nTier architecture as our little mORMot offers, we often have to persist some private keys in a safe way.
Problem with such keys is that they consist in small amount of bytes (typically 16 or 32 bytes), easy to be left somewhere in disk or memory.
Given the abilities of recent forensic data recovery methods, data can't be destroyed on magnetic or flash storage media reliably.

We have just added to our SynCrypto OpenSource library the Anti-forensic Information Splitter algorithm, as proposed in TKS1, and implemented in the LUKS standard.
LUKS is the de-facto standard of platform-independent standard on-disk format for use in various tools.

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2016-04-09

AES-256 based Cryptographically Secure Pseudo-Random Number Generator (CSPRNG)

Everyone knows about the pascal random() function.
It returns some numbers, using a linear congruential generator, with a multiplier of 134775813, in its Delphi implementation.
It is fast, but not really secure. Output is very predictable, especially if you forgot to execute the RandSeed() procedure.

In real world scenarios, safety always requires random numbers, e.g. for key/nonce/IV/salt/challenge generation.
The less predictable, the better.
We just included a Cryptographically Secure Pseudo-Random Number Generator (CSPRNG) into our SynCrypto.pas unit.
The TAESPRNG class would use real system entropy to generate a sequence of pseudorandom bytes, using AES-256, so returning highly unpredictable content.

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2016-01-09

Safe locks for multi-thread applications

Once your application is multi-threaded, concurrent data access should be protected. We already wrote about how debugging multi-thread applications may be hard.
Otherwise, a "race condition" issue may appear: for instance, if two threads modify a variable at the same time (e.g. decrease a counter), values may become incoherent and unsafe to use. Another symptom of broken logic is the "deadlock", by which the whole application appears to be blocked and unresponsive, when two threads have a wrong use of the lock, so are blocking each-others.
On a server system, which is expected to run 24/7 with no maintenance, such issues are to be avoided.

In Delphi, protection of a resource (which may be an object, or any variable) is usually done via Critical Sections.
A critical section is an object used to make sure, that some part of the code is executed only by one thread at a time. A critical section needs to be created/initialized before it can be used and be released when it is not needed anymore. Then, some code is protected using Enter/Leave methods, which would lock its execution: in practice, only a single thread would own the critical section, so only a single thread would be able to execute this code section, and other threads would wait until the lock is released. For best performance, the protected sections should be as small as possible - otherwise the benefit of using threads may be voided, since any other thread would wait for the thread owning the critical section to release the lock.

We will now see that Delphi's TCriticalSection may have potential issues, and what our framework proposes to ease critical section use in your applications.

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2015-12-11

Audit Trail for Services

We have seen previously how the ORM part of the framework is able to provide an Audit Trail for change tracking.
It is a very convenient way of storing the change of state of the data.

On the other side, in any modern SOA solution, data is not at the center any more, but services.
Sometimes, the data is not stored within your server, but in a third-party Service-Oriented Architecture (SOA).
Being able to monitor the service execution of the whole system becomes sooner or later mandatory.

Our framework allows to create an Audit Trail of any incoming or outgoing service operation, in a secure, efficient and automated way.

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2015-11-17

Benefits of interface callbacks instead of class messages

If you compare with existing client/server SOA solutions (in Delphi, Java, C# or even in Go or other frameworks), mORMot's interface-based callback mechanism sounds pretty unique and easy to work with.

Most Events Oriented solutions do use a set of dedicated messages to propagate the events, with a centralized Message Bus (like MSMQ or JMS), or a P2P/decentralized approach (see e.g. ZeroMQ or NanoMsg). In practice, you are expected to define one class per message, the class fields being the message values. You would define e.g. one class to notify a successful process, and another class to notify an error. SOA services would eventually tend to be defined by a huge number of individual classes, with the temptation of re-using existing classes in several contexts.

Our interface-based approach allows to gather all events:

  • In a single interface type per notification, i.e. probably per service operation;
  • With one method per event;
  • Using method parameters defining the event values.

Since asynchronous notifications are needed most of the time, method parameters would be one-way, i.e. defined only as const - in such case, an evolved algorithm would transparently gather those outgoing messages, to enhance scalability when processing such asynchronous events. Blocking request may also be defined as var/out, as we will see below, inWorkflow adaptation.

Behind the scene, the framework would still transmit raw messages over IP sockets (currently over a WebSockets connection), like other systems, but events notification would benefit from using interfaces, on both server and client sides.
We will now see how...

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2015-09-28

mORMot show case: Illustrated Spare Parts Catalog

Illustrated Spare Parts Catalog is, as its name suggests, a software for creating and publishing spare parts catalogs. It uses mORMot for client-server communication and ORM, and SynPdf for the reporting. Sounds like a powerful solution. It is also a testimony that you could use big databases (20 GB  […]

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2015-09-25

ORM TNullable* fields for NULL storage

In Delphi code, NULLable types do not exist as such. There is no native int? type, as in C#.
But at SQL and JSON levels, the NULL value does exist and should be converted as expected by the ORM.

In SQLite3 itself, NULL is handled as stated in http://www.sqlite.org/lang_expr.html (see e.g. IS and IS NOT operators).
It is worth noting that NULL handling is not consistent among all existing database engines, e.g. when you are comparing NULL with non NULL values... so we recommend using it with care in any database statements, or only with proper (unit) testing, when you switch from one database engine to another.

By default, in the mORMot ORM/SQL code, NULL will appear only in case of a BLOB storage with a size of 0 bytes.
Otherwise, you should not see it as a value, in most kinds of ORM properties.

Null-oriented value types have been implemented in our framework, since the object pascal language does not allow defining a nullable type (yet)

We choose to store those values as variant, with a set of TNullable dedicated types, as defined in mORMot.pas:

type
  TNullableInteger = type variant;
  TNullableBoolean = type variant;
  TNullableFloat = type variant;
  TNullableCurrency = type variant;
  TNullableDateTime = type variant;
  TNullableTimeLog = type variant;
  TNullableUTF8Text = type variant;

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2015-08-23

"SQL and NoSQL", not "SQL vs NoSQL"

You know certainly that our mORMot Open Source framework is an ORM, i.e. mapping objects to a relational / SQL database (Object Relational Mapping).
You may have followed also that it is able to connect to a NoSQL database, like MongoDB, and that the objects are then mapped via an ODM (Object Document Mapping) - the original SQL SELECT are even translated on the fly to MongoDB queries.

But thanks to mORMot, it is not "SQL vs NoSQL" - but "SQL and NoSQL".
You are not required to make an exclusive choice.
You can share best of both worlds, depending on your application needs.

In fact, the framework is able to add NoSQL features to a regular relational / SQL database, by storing JSON documents in TEXT columns.

In your end-user code, you just define a variant field in the ORM, and store a TDocVariant document within.
We also added some dedicated functions at SQL level, so that SQLite3 could be used as embedded fast engine, and provide advanced WHERE clauses on this JSON content.

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2015-08-15

Breaking Change in mORMot WebSockets binary protocol

Among all its means of transmission, our mORMot framework features WebSockets, allowing bidirectional communications, and interface-based callbacks for real time notification of SOA events.
After several months of use in production, we identified some needed changes for this just emerged feature.

We committed today a breaking change of the data layout used for our proprietary WebSockets binary protocol.
From our tests, it would increase the performance and decrease the resource consumption, especially in case of high number of messages.

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2015-07-14

New blog about mORMot

An enthusiastic mORMot user, named willo in the forum, just started a blog about his experiments with our framework.

The information there is clear, simple, and right to the point.
If you are a little lost in our huge documentation, it is a good place to start!

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2015-06-30

Faster String process using SSE 4.2 Text Processing Instructions STTNI

A lot of our code, and probably yours, is highly relying on text process. In our mORMot framework, most of its features use JSON text, encoded as UTF-8. Profiling shows that a lot of time is spent computing the end of a text buffer, or comparing text content. You may know that In its SSE4.2 feature  […]

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2015-06-16

Handling Cross-Platform Time Zones

One common problem when handling dates and times, is that time is shown and entered as local, whereas the computer should better use non-geographic information - especially on a Client-Server architecture, where both ends may not be on the same physical region.

A time zone is a region that observes a uniform standard time for legal, commercial, and social purposes.
Time zones tend to follow the boundaries of countries and their subdivisions because it is convenient for areas in close commercial or other communication to keep the same time.
Most of the time zones on land are offset from Coordinated Universal Time (UTC) by a whole number of hours, or minutes.
Even worse, some countries use daylight saving time for part of the year, typically by changing clocks by an hour, twice every year.

The main rule is that any date and time stored should be stored in UTC, or with an explicit Zone identifier (i.e. an explicit offset to the UTC value).
Our framework expects this behavior: every date/time value stored and handled by the ORM, SOA, or any other part of it, is expected to be UTC-encoded.
At presentation layer (e.g. the User Interface), conversion to/from local times should take place, so that the end-user is provided with friendly clock-wall compatible timing.

As you may guess, handling time zones is a complex task, which should be managed by the Operating System itself.
Since this cultural material is constantly involving, it is updated as part of the OS.

In practice, current local time could be converted from UTC from the current system-wide time zone. One of the only parameters you have to set when installing an Operating System is to pickup the keyboard layout... and the current time zone to be used. But in a client-server environment, you may have to manage several time zones on the server side: so you can't rely on this global setting.

One sad - but predictable - news is that there is no common way of encoding time zone information.
Under Windows, the registry contains a list of time zones, and the associated time bias data. Most POSIX systems (including Linux and Mac OSX) do rely on the IANA database, also called tzdata - you may have noticed that this particular package is often updated with your system.
Both zone identifiers do not map, so our framework needed something to be shared on all systems.

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2015-06-01

Updated Slides about ORM SOA MVC SOLID DDD

One year ago, we published a set of slides about the main concepts implemented by our framework. Mainly about ORM (and ODM), NoSQL, JSON, SOA, MVC (and MVVM), SOLID, DDD, CQRS and some patterns like Stubs, Mocks, Factory, Repository, Unit-Of-Work. Worth a look, if you want to find out the benefits  […]

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