|By James H. Wong||
|December 9, 2012 04:00 PM EST||
Designing and implementing a hybrid encryption application is a big challenge but without a supporting infrastructure it's almost impossible. There are open source libraries that allow you to encrypt a file but only provide the translation technique. After the information has been encrypted, how do you know what algorithm was used, who you encrypted it, what version did you used, etc. In order to decrypt the protected message or file, a well-defined cryptographic header provides all the information required. This also applies if the encrypted data is digitally signed and the recipient wants to validate the signature.
This article will address one of the critical components of a support infrastructure by providing a design of a cryptographic header used to precede encrypted and/or digitally signed messages and files. The header is used within an application known as DocuArmor that was written using Java and the Cryptography library from the BouncyCastle organization and designed by Logical Answers Inc. The header will store information used when encrypting and/or digitally signing a message or file and allow the recipient to decrypt the information and/or verify the digital signature. With a properly designed header, a person can encrypt their personal files as well as exchange confidential messages and authenticate the sender.
In order to encrypt personal files and exchange protected data, we use a hybrid technique with two types of encryption, symmetric and asymmetric.
Symmetric encryption uses a single key to hide the message and reveal the message. There are several symmetric algorithms available such as AES (the Advanced Encryption Standard) but the important thing to remember is that the file can be encrypted and decrypted using the same key. An example is the Caesar cipher that shifts the letters of the alphabet by a specific number. If the shift is 2 (single key) then we get the following translation; a=c, b=d, c=e, ..., z=b.
Asymmetric encryption uses a pair of keys (public, private) to hide and reveal the message and the RSA algorithm is most commonly used. The RSA algorithm was credited in 1977 to Ronald Rivest, Adi Shamir, and Leonard Adleman. Sometimes referred to as Public Key Infrastructure (PKI), the pubic key is used to encrypt data and the private key is used to decrypt data.
Figure 1: Public and Private Key Functions
The hybrid technique uses the symmetric key to encrypt a file. The asymmetric public key is used to encrypt the symmetric key and is placed in the header. When the recipient receives an encrypted file, the encrypted symmetric key is extracted from the header. The encrypted symmetric key is decrypted using the private key. The file is decrypted using the symmetric key.
The same pair of keys can be used with digital signatures. The private key is used to generate a digital signature from a file and inserted into the header. The public key is used to verify the authenticity of the signature.
When two people want to exchange encrypted files, they each generate a pair of asymmetric keys and exchange a copy of their public keys. By using the other person's public key, they can encrypt a file, storing the cryptographic information in the header and then e-mail it to the recipient. The recipient will use the header to extract a symmetric key with their private key and decrypt the accompanying file. If a digital signature is included, the recipient can authenticate the sender.
Figure 2: Exchange of Encrypted Files
When a file is encrypted, digitally signed or both, a Cryptographic header is placed in front of the resulting file and has the following structure. The structure consists of two sections, the header and the encrypted/plain file contents.
Figure 3: Encrypted File Structure
The header structure contains information required to reverse the encryption process and decrypt the contents of the file or verify the digital signature. The header contains the total length, an ID, version, and two sections containing encryption and digital signature information. Using Java, you can write out the contents of header within a byte stream as well as read it back in.
Figure 4: Cryptographic Header Structure
- Total Len: Contains the total length of the header (stored as a 4 byte integer)
- Header ID: Contains the string "LAHEADER" to identify the file (16 bytes)
- Header Version: Structural version of the header (stored as a 4 byte integer)
- Encryption Information: Holds the algorithm, mode, encrypted symmetric key, etc.
- Digital Signature Information: Holds digital signature
The Encryption Information structure contains information that was used to encrypt the contents of the file and later decrypt the file. The symmetric key and initialization vector is encrypted with the recipient's asymmetric public key. The recipient could be the owner if you are encrypting a file for yourself or another user you want to send confidential information to.
An additional field has been allocated to allow the encryption of the symmetric key with another set of asymmetric keys. For example, if owner A is sending an encrypted file to another person B, the symmetric key can be encrypted with B's public key as well as A's public key so that either person can decrypt the file.
Alternatively, an employee can encrypt a file with their public key and a corporation could insert an encrypted symmetric key into the header using their asymmetric keys. The corporation's asymmetric keys can be a Certifying Authority (CA), which can be used to issue employee keys.
Figure 5: Encryption Information Structure
- Encrypt Flag: (Y/N - 2 bytes) specifies whether the file is encrypted.
- Decrypt ID Length: (integer - 4 bytes) length in chars(bytes) of the Key ID.
- Decrypt ID: (size varies) an identifier of the RSA keys used in the encryption/decryption process. It is the alias associated to the asymmetric encryption keys (e.g., JaneDoe_12ff).
- Other Decrypt ID Length: (integer - 4 bytes) length in chars(bytes) of the Key ID.
- Other Decrypt ID: (size varies) an identifier of the RSA keys used in the encryption/decryption process. It can be the alias or the common name (e.g., JaneDoe_12ff or Logical Answers CA).
- Symmetric Key Algorithm: (integer - 4 bytes) specifies the symmetric key algorithm used to encrypt the file. The default value is 1=AES.
- Symmetric Key Mode: (integer - 4 bytes) specifies the symmetric key block cipher mode used to enhance confidentiality. The default value is 5=Segmented Integer Counter mode (CTR).
- Symmetric Key Padding: (integer - 4 bytes) specifies the type of padding for block cipher. The default value is 1=No Padding
- Wrapped Symmetric Key Length: (integer - 4 bytes)
- Wrapped Symmetric Key: (size varies) symmetric key used to encrypt/decrypt the file and encrypted with the asymmetric key.
- Initialization Vector Length: (integer - 4 bytes)
- Initialization Vector: (byte - size varies) vector used with the symmetric encryption process.
- Other Wrapped Symmetric Key Length: (integer - 4 bytes)
- Other Wrapped Symmetric Key: (size varies) symmetric key used to encrypt/decrypt the file and encrypted with another person's asymmetric key.
- Other Initialization Vector Length: (integer - 4 bytes)
- Other Initialization Vector: (byte - size varies) vector used with the symmetric encryption process.
Digital Signature Information
The Digital Signature Information structure contains information used to add or verify a digital signature generated from the contents of the file. The digital signature is generated with the owner's private key using a specific algorithm and then inserted into the header. When the recipient receives the signed file, they can use the signer's public key to validate its authenticity. If the signature is authenticated, it implies the file has not been altered and the holder of the private key generated the signature.
Figure 6: Digital Signature Information Structure
- Signed Flag: (Y/N - 2 bytes) specifies whether the file contains a digital signature
- Signature Algorithm: (integer - 4 bytes) specifies the algorithm used to generate the digital signature. The default value is 12= SHA512WithRSAEncryption
- Verify Signature Cert Name Length: (integer - 4 bytes) length in chars(bytes) of the filename of the certificate used to verify a digital signature
- Verify Signature Cert Name: (size varies) filename of the certificate holding the RSA public key used to verify the digital signature of a file (e.g., JaneDoe_fa39.cer).
- Signature Date/Time: (long - 8 bytes) date the digital signature was generated.
- Signature Length: (integer - 4 bytes)
- Signature: (size varies) holds digital signature generated with RSA private key and signature engine
File Naming Conventions
The Cryptographic header holds information that designates which keys were used to encrypt a file but it's not physically accessible without reading it in first. With proper naming conventions, you can determine who the intended recipient is for encrypted files - whether it is for yourself or a colleague. When you generate your pair of asymmetric encryption keys using Java, store them in a file called a key store. The key store holds a pair of asymmetric keys as an entry with a unique alias. The alias typically consists of the initial of your first name and your last name. To make it more unique, you can extract 4 hex digits from your public key and append an underline and the hex digits to the alias. For example, if the person's name was Jane Smith, then the resulting unique alias would be jsmith_ad5e. A certificate holds a person's public key and the alias would be used in the filename, as jsmith_ad5e.cer. Similarly, the key store holding the pair of asymmetric keys would be saved as, jsmith_ad5e.jks.
Following the unique alias analogy, Jane Smith could encrypt files for herself and the file name would be appended with her alias and an appropriate file extension. For example, if Jane encrypted a personal file, myTaxes.txt, then the result would be myTaxes.txt.jsmith_ad5e.aes. If Jane wanted to send her colleague Dick an encrypted document, she would use Dick's certificate to encrypt it. If Dick's certificate is djones_9fa2, Jane could encrypt the file, comments.doc, for Dick and the resulting file would be comments.doc.djones_9fa2.aes. When Dick receives the file, he knows it is for him by recognizing his alias on the file name.
The unique alias is stored within the header. This reinforces the importance of having a well-defined Cryptographic header for implementing encryption within your applications.
A well-defined cryptographic header stores the information required to encrypt, decrypt and digitally sign a file. Along with facilitating the implementation of standard cryptographic functions, the header also provides the following benefits:
- The header allows for the protection of personal files as well as the exchange of confidential data.
- Using the stored digital signature, the recipient can determine if the sender is valid and whether file has been altered.
- The header allows either the sender or recipient to decrypt the encrypted file since both would encrypt the symmetric key with their public key.
- Using the concept of a Certifying Authority pair of asymmetric keys, a corporation, group, or family could issue pairs of asymmetric keys to their employees or members and decipher files encrypted by them in case of emergencies.
- The header allows for using different combinations of symmetric algorithms, modes, padding and key sizes to be used to encrypt information.
- The header version allows for enhancements to be added to the structure for implementing new functions and still support older versions.
References and Other Technical Notes
- Computer running Windows XP or higher...
- Java Runtime (JRE V1.6 or higher)
- The Legion of the Bouncy Castle Encryption Modules (no runtime fee)
- DocuArmor software modules by Logical Answers Inc.
- "Beginning Cryptography with Java" by David Hook.
- "The Code Book" by Simon Singh
The 3rd International Internet of @ThingsExpo, co-located with the 16th International Cloud Expo - to be held June 9-11, 2015, at the Javits Center in New York City, NY - announces that its Call for Papers is now open. The Internet of Things (IoT) is the biggest idea since the creation of the Worldwide Web more than 20 years ago.
Nov. 28, 2014 05:00 PM EST Reads: 1,302
Cultural, regulatory, environmental, political and economic (CREPE) conditions over the past decade are creating cross-industry solution spaces that require processes and technologies from both the Internet of Things (IoT), and Data Management and Analytics (DMA). These solution spaces are evolving into Sensor Analytics Ecosystems (SAE) that represent significant new opportunities for organizations of all types. Public Utilities throughout the world, providing electricity, natural gas and water, are pursuing SmartGrid initiatives that represent one of the more mature examples of SAE. We have s...
Nov. 27, 2014 04:00 PM EST Reads: 1,374
The security devil is always in the details of the attack: the ones you've endured, the ones you prepare yourself to fend off, and the ones that, you fear, will catch you completely unaware and defenseless. The Internet of Things (IoT) is nothing if not an endless proliferation of details. It's the vision of a world in which continuous Internet connectivity and addressability is embedded into a growing range of human artifacts, into the natural world, and even into our smartphones, appliances, and physical persons. In the IoT vision, every new "thing" - sensor, actuator, data source, data con...
Nov. 27, 2014 04:00 PM EST Reads: 1,704
How do APIs and IoT relate? The answer is not as simple as merely adding an API on top of a dumb device, but rather about understanding the architectural patterns for implementing an IoT fabric. There are typically two or three trends: Exposing the device to a management framework Exposing that management framework to a business centric logic Exposing that business layer and data to end users. This last trend is the IoT stack, which involves a new shift in the separation of what stuff happens, where data lives and where the interface lies. For instance, it's a mix of architectural styles ...
Nov. 27, 2014 03:00 PM EST Reads: 1,382
The Internet of Things is tied together with a thin strand that is known as time. Coincidentally, at the core of nearly all data analytics is a timestamp. When working with time series data there are a few core principles that everyone should consider, especially across datasets where time is the common boundary. In his session at Internet of @ThingsExpo, Jim Scott, Director of Enterprise Strategy & Architecture at MapR Technologies, discussed single-value, geo-spatial, and log time series data. By focusing on enterprise applications and the data center, he will use OpenTSDB as an example t...
Nov. 27, 2014 03:00 PM EST Reads: 1,522
An entirely new security model is needed for the Internet of Things, or is it? Can we save some old and tested controls for this new and different environment? In his session at @ThingsExpo, New York's at the Javits Center, Davi Ottenheimer, EMC Senior Director of Trust, reviewed hands-on lessons with IoT devices and reveal a new risk balance you might not expect. Davi Ottenheimer, EMC Senior Director of Trust, has more than nineteen years' experience managing global security operations and assessments, including a decade of leading incident response and digital forensics. He is co-author of t...
Nov. 27, 2014 01:00 PM EST Reads: 1,714
The Internet of Things will greatly expand the opportunities for data collection and new business models driven off of that data. In her session at @ThingsExpo, Esmeralda Swartz, CMO of MetraTech, discussed how for this to be effective you not only need to have infrastructure and operational models capable of utilizing this new phenomenon, but increasingly service providers will need to convince a skeptical public to participate. Get ready to show them the money!
Nov. 27, 2014 11:00 AM EST Reads: 1,329
The Internet of Things will put IT to its ultimate test by creating infinite new opportunities to digitize products and services, generate and analyze new data to improve customer satisfaction, and discover new ways to gain a competitive advantage across nearly every industry. In order to help corporate business units to capitalize on the rapidly evolving IoT opportunities, IT must stand up to a new set of challenges. In his session at @ThingsExpo, Jeff Kaplan, Managing Director of THINKstrategies, will examine why IT must finally fulfill its role in support of its SBUs or face a new round of...
Nov. 27, 2014 10:00 AM EST Reads: 1,266
One of the biggest challenges when developing connected devices is identifying user value and delivering it through successful user experiences. In his session at Internet of @ThingsExpo, Mike Kuniavsky, Principal Scientist, Innovation Services at PARC, described an IoT-specific approach to user experience design that combines approaches from interaction design, industrial design and service design to create experiences that go beyond simple connected gadgets to create lasting, multi-device experiences grounded in people's real needs and desires.
Nov. 27, 2014 08:00 AM EST Reads: 1,293
Enthusiasm for the Internet of Things has reached an all-time high. In 2013 alone, venture capitalists spent more than $1 billion dollars investing in the IoT space. With "smart" appliances and devices, IoT covers wearable smart devices, cloud services to hardware companies. Nest, a Google company, detects temperatures inside homes and automatically adjusts it by tracking its user's habit. These technologies are quickly developing and with it come challenges such as bridging infrastructure gaps, abiding by privacy concerns and making the concept a reality. These challenges can't be addressed w...
Nov. 27, 2014 07:45 AM EST Reads: 1,568
The Domain Name Service (DNS) is one of the most important components in networking infrastructure, enabling users and services to access applications by translating URLs (names) into IP addresses (numbers). Because every icon and URL and all embedded content on a website requires a DNS lookup loading complex sites necessitates hundreds of DNS queries. In addition, as more internet-enabled ‘Things' get connected, people will rely on DNS to name and find their fridges, toasters and toilets. According to a recent IDG Research Services Survey this rate of traffic will only grow. What's driving t...
Nov. 27, 2014 07:00 AM EST Reads: 1,536
Connected devices and the Internet of Things are getting significant momentum in 2014. In his session at Internet of @ThingsExpo, Jim Hunter, Chief Scientist & Technology Evangelist at Greenwave Systems, examined three key elements that together will drive mass adoption of the IoT before the end of 2015. The first element is the recent advent of robust open source protocols (like AllJoyn and WebRTC) that facilitate M2M communication. The second is broad availability of flexible, cost-effective storage designed to handle the massive surge in back-end data in a world where timely analytics is e...
Nov. 27, 2014 06:45 AM EST Reads: 1,372
Scott Jenson leads a project called The Physical Web within the Chrome team at Google. Project members are working to take the scalability and openness of the web and use it to talk to the exponentially exploding range of smart devices. Nearly every company today working on the IoT comes up with the same basic solution: use my server and you'll be fine. But if we really believe there will be trillions of these devices, that just can't scale. We need a system that is open a scalable and by using the URL as a basic building block, we open this up and get the same resilience that the web enjoys.
Nov. 27, 2014 06:45 AM EST Reads: 1,434
"Matrix is an ambitious open standard and implementation that's set up to break down the fragmentation problems that exist in IP messaging and VoIP communication," explained John Woolf, Technical Evangelist at Matrix, in this SYS-CON.tv interview at @ThingsExpo, held Nov 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA.
Nov. 27, 2014 04:00 AM EST Reads: 1,237
We are reaching the end of the beginning with WebRTC, and real systems using this technology have begun to appear. One challenge that faces every WebRTC deployment (in some form or another) is identity management. For example, if you have an existing service – possibly built on a variety of different PaaS/SaaS offerings – and you want to add real-time communications you are faced with a challenge relating to user management, authentication, authorization, and validation. Service providers will want to use their existing identities, but these will have credentials already that are (hopefully) i...
Nov. 27, 2014 04:00 AM EST Reads: 1,282
P2P RTC will impact the landscape of communications, shifting from traditional telephony style communications models to OTT (Over-The-Top) cloud assisted & PaaS (Platform as a Service) communication services. The P2P shift will impact many areas of our lives, from mobile communication, human interactive web services, RTC and telephony infrastructure, user federation, security and privacy implications, business costs, and scalability. In his session at @ThingsExpo, Robin Raymond, Chief Architect at Hookflash, will walk through the shifting landscape of traditional telephone and voice services ...
Nov. 26, 2014 02:00 PM EST Reads: 1,658
Explosive growth in connected devices. Enormous amounts of data for collection and analysis. Critical use of data for split-second decision making and actionable information. All three are factors in making the Internet of Things a reality. Yet, any one factor would have an IT organization pondering its infrastructure strategy. How should your organization enhance its IT framework to enable an Internet of Things implementation? In his session at Internet of @ThingsExpo, James Kirkland, Chief Architect for the Internet of Things and Intelligent Systems at Red Hat, described how to revolutioniz...
Nov. 24, 2014 07:00 PM EST Reads: 1,756
Bit6 today issued a challenge to the technology community implementing Web Real Time Communication (WebRTC). To leap beyond WebRTC’s significant limitations and fully leverage its underlying value to accelerate innovation, application developers need to consider the entire communications ecosystem.
Nov. 24, 2014 12:00 PM EST Reads: 1,652
The definition of IoT is not new, in fact it’s been around for over a decade. What has changed is the public's awareness that the technology we use on a daily basis has caught up on the vision of an always on, always connected world. If you look into the details of what comprises the IoT, you’ll see that it includes everything from cloud computing, Big Data analytics, “Things,” Web communication, applications, network, storage, etc. It is essentially including everything connected online from hardware to software, or as we like to say, it’s an Internet of many different things. The difference ...
Nov. 24, 2014 11:00 AM EST Reads: 1,789
Cloud Expo 2014 TV commercials will feature @ThingsExpo, which was launched in June, 2014 at New York City's Javits Center as the largest 'Internet of Things' event in the world.
Nov. 24, 2014 09:00 AM EST Reads: 1,818