Optimized Cryptography Components for Constrained Environments · OPTIMIZED CRYPTOGRAPHY COMPONENTS . FOR CONSTRAINED ENVIRONMENTS. ... Digests: MD2, MD5, SHA-1, ... so please consult

OPTIMIZED CRYPTOGRAPHY COMPONENTS FOR CONSTRAINED ENVIRONMENTSRSA BSAFE® Crypto Kernel

Solution Brief

RSA Solution Brief

RSA BSAFE Crypto Kernel leverages over 20 years of RSA expertise in delivering high-

quality data security toolkits for device and software manufacturers. It is a collection of

high- performance, small code-size cryptographic source code components that help

embedded system developers meet their security requirements by:

– Providing low-level cryptographic APIs which give developers maximum flexibility in their

security implementations,

– Offering high-performance and small code-size implementations of popular

cryptographic algorithms—giving developers many choices to meet constrained device

requirements,

– Delivering broad platform support, with customization services available to optimize for

specific customer platforms,

– Providing assembler-level optimizations for popular processors and

– Offering a wide variety of professional services to help tailor BSAFE components to meet

special requirements.

Designing and developing secure applications has always been a difficult task, especially

for embedded system developers that must code for highly constrained operating

environments. However, improperly secured applications greatly increase the risk of

exposure of sensitive user information, intellectual property or other device information

that could potentially compromise the entire system. Security needs are becoming just as

important as feature enhancements for mobile devices.

Good security requires good design, but how do you achieve good design without greatly

increasing costs and delivery schedules? Designing applications using the RSA BSAFE®

Crypto Kernel allows you to achieve a solid, secure application design without greatly

increasing development time lines or costs. Crypto Kernel offers versions of popular

cryptographic algorithms optimized for both small code size and high performance. This

helps address concerns like preserving battery life and working with the limited system

memory common in embedded environments. And, unlike alternatives such as open

source, RSA BSAFE technology is backed by highly regarded cryptography experts in the

RSA® Professional Services, Worldwide Support and RSA® Laboratories organizations.

EFFICIENT CRYPTOGRAPHY FOR CONSTRAINED ENVIRONMENTS

Persistent protection of your intellectual property and user data requires data security

technology that can be quickly optimized for specific needs. Particularly in constrained

environments, every line of code counts. Developers securing embedded environments

must make calculated trade-offs between code size, performance and interoperability.

However, reducing code size does not mean the sacrifice of effective security

enforcement. Regardless of where sensitive information is ultimately stored, using the

capabilities of RSA BSAFE Crypto Kernel in your application will help provide a persistent

level of protection, lessening the risk of compromise.

RSA solutions are built on open and proven industry standards, many of which have been

developed and championed by RSA. The company has a wide body of knowledge about

potential vulnerabilities and how to address them using standards-based algorithms.

Because of assembly-level optimizations on key processors, Crypto Kernel can provide

developers with algorithm implementations at increased speeds on many popular

platforms. Developers can rely on RSA to be a trusted security expert, enabling them to

stay focused on developing the core functionality users want.

In addition, RSA Professional Services offers application security design assessment

services that can help spot existing vulnerabilities in applications during development,

as well as help make design decisions which avoid problems later. The Professional

Services organization also offers customization services to help with porting to

specialized processors or meeting specific code size and performance requirements

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RSA solutions are built on

open and proven industry

standards, many of which

have been developed and

championed by RSA.

FIPS 140-2 out-of-the-box

ANSI-C support

Limited level of abstraction of cryptography

Uses Crypto Kernel as its engine

ANSI-C support

Very low-level APIs

Optimized for size and performance

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Figure 1

RSA Solution Brief

outside the scope of RSA’s pre-built components. Working with RSA to design

applications securely will help establish trust with your users and limit the risk for you

and your customers and partners.

RSA BSAFE Crypto Kernel provides the cryptographic foundation for the RSA BSAFE

security products designed for C/C++ developers. As shown in figure 1, Crypto Kernel is

designed to offer the lowest level cryptographic application programming interfaces. The

RSA BSAFE® Crypto-C Micro Edition (ME) product uses Crypto Kernel as its cryptography

engine and provides a higher level of abstraction of the cryptographic functionality.

RSA BSAFE Crypto Kernel is offered currently as source code through RSA Professional

Services. Your purchase of Crypto Kernel includes a license to algorithm source code for

the chosen processor and operating environment as well as services needed to optimize

the code for your specific constraints. Services are also available for porting to additional

processors and operating systems or for specific optimizations not provided in the pre-

built components. Because of the specialized nature of applications that use Crypto

Kernel, it is custom-supported through Professional Services to ensure the highest level

of service.

RSA BSAFE Crypto Kernel is a collection of cryptographic algorithm implementations

provided as source code (rather than a software library) with a simple API to keep code

size small. Crypto Kernel offers multiple implementations of the same algorithm to allow

developers the flexibility of trading off performance and code size.

Crypto Kernel includes the algorithms most often used by embedded system developers.

These algorithms are a subset of those included in RSA BSAFE Crypto-C Micro Edition

(ME). By design, Crypto Kernel does not offer the smallest algorithm implementations

possible out-of-the-box since this would not meet portability and maintainability goals.

Professional Services are available to further constrain code size of a particular

implementation, if required.

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Algorithms typES Notes

Ciphers RC4, RC2, RC5, AES, DES, 3DES Modes: ECB, CBC, CFB, OFB, CTR, CCM, XTS, GCM

Digests MD2, MD5, SHA-1, SHA-224, SHA-256, SHA-384, SHA-512

Modes: HMAC, CBC-MAC

Public key RSA Padding schemes: PKCS#1, PSS, OAEP, and X9.31

Public key DSA

Public key Elliptic curve cryptography (ECC): ECDSA, EC key generation, ECIES

Named pime curves: NIST_P256, NIST_P384, NIST_P521 Named F2M Curves in polynomial and ONB formats: NIST_K283, NIST_B283, NIST_K409, NIST_B409, NIST_K571, NIST_B571

Key derivation function X9.63

Key Exchange Diffie-Hellman, ECDH

Key wrapping AES key wrapping (X9.102, RFC 3394)

Random number generation Elliptic curve deterministic random bit generator (ECDRBG), HMAC DRBG, FIPS 186-2 random

Table 1. Algorithms Supported by RSA BSAFE Crypto Kernel

RSA Solution Brief

CODE STRUCTURE

Platform-specific assembler code is found at the lowest level of Crypto Kernel, the r0

level. At the next level up, the R1 level, is the lowest level of APIs which are made public.

The next level, the R2 level, provides a higher level API such as public key algorithm sign

and verify. And at the R level are functions for allocating memory, benchmarking and

testing (see figure 2).

USING CRYPTO KERNEL

Similar to the interfaces provided by other RSA BSAFE and third-party cryptography

toolkits, to use Crypto Kernel developers first create a “context” (the operation being

performed), supplying a “method” (implementation code). Developers configure the

“context” via “set/get” calls, perform the operation and then cleanup.

Crypto Kernel is built out of a directory tree with make files. If an Integrated Development

Environment (IDE) is being used, a list of all files can be generated which can then be

inserted into the IDE and compiled.

SUPPORTED FEATURES

Algorithms

Crypto Kernel supports the most commonly used ciphers, digests and public key

algorithms. Table 1 lists those supported by the current versions of Crypto Kernel.

For each algorithm, typically four implementations are offered. Not all implementations

are available for every algorithm, so please consult with an RSA sales representative for

details on which are available for your specific needs. The four implementations typically

offered are:

– C/C++ source — for easy portability,

– “Fast” — for the fastest code possible using code switching depending on the CPU, and

typically written in assembler. “Efficient” is another description of this implementation,

since an operation completed quickly saves battery power. With the “fast”

implementation, code size is given little consideration,

– “Small” — an implementation that balances code size and performance in the best

manner possible for a given algorithm and

– “Tiny” — for the smallest code size possible at the expense of performance.

To illustrate the difference a chosen implementation can make, table 2 shows the

performance and size measurements for a Linux ARM, 126MHz XScale, with a gcc

compiler for the “fast” and “small” implementations.

In the case of the SHA-1 digest, using the “small” implementation saves almost 5KB of

code size at about 60% of the performance of the “fast” implementation.

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R2 higher-level API, built on R1 routines

R1 Crypto primitive API routines

R0 low level routines (subject to change)

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Figure 2. Code Structure

Speed (bytes / second) Size (bytes) Size (bytes) Speed (operations/second)

Fast 6,264,000 10,901 10,901 383

Small 3,773,000 6,013 17,331 98

Table 2. Performance and size Measurements for a Linux ARM

SHA-1 Message Digest RSA PKCS#1 Verification

RSA Solution Brief

For the RSA PKCS#1 verification operation, the “small” implementation saves about 4KB

of code size though performs at about one-quarter the speed of the “fast”

implementation.

ASN.1 parsing and memory allocation

Crypto Kernel also includes support for simple ASN.1 parsing, as well as an optional

memory allocation object. If a platform supports a native memory allocator, developers

can compile out all of Crypto Kernel’s memory allocation code to further limit code size.

Crypto Kernel includes five memory allocators:

– the standard UNIX-style memory allocator,

– Win32 heaps — for the Win32 platforms,

– Static — memory is allocated from a supplied memory block. This is especially useful for

threaded applications where there is a different block of memory for each thread and

– Stats — to measure memory usage so that developers can find the maximum memory

used.

In the embedded space, there is a wide range of operating systems. Though Crypto

Kernel supports a number of platforms, many users have requested a platform

unavailable from the above list. In this case, either RSA Professional Services can port

Crypto Kernel to the necessary platform or source code can be provided so that

developers can perform their own porting.

USE CASES

These use cases illustrate how developers have used RSA BSAFE Crypto Kernel software

to develop secure applications for their embedded system environments. These

applications reflect the most common uses of Crypto Kernel.

Secure over-the-air distribution for mobile devices

This manufacturer wanted to provide secure updates to firmware following the Open

Mobile Alliance’s Firmware-Over-the-Air distribution method. To authenticate the firmware

before downloading, the manufacturer needed an implementation of RSA SHA1 signature

verification in less than 30KB. Crypto Kernel was able to meet this demanding size

requirement, something the manufacturer was unable to accomplish with open source

security software or cryptography developed by in-house developers.

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Unlike open source, RSA

BSAFE technology is

backed by highly regarded

cryptography experts

in the RSA Professional

Services, Worldwide

Support and Laboratories

organizations.

Platform CoMpilER Processor

AIX aixC PowerPC, PowerPC64

Cygwin gcc x86

HP-UX gcc, hpc PA-RISC (1.1, 2.0, 2.0W), IA64 (32-bit and 64-bit)

Linux gcc, icc x86, x86_64, ARM4L, ARM4B, MIPS32, IA64, PowerPC

Solaris gcc, sunc SPARC (v8, v8+, v9), x86, x86_64

Win32 msvs, icc x86, x86_64

Windows CE msvs ARM4L, MIPS32, SH3

VxWorks gcc ARM4L, ARM4B, MIPS32, PowerPC

Table 3. Crypto Kernel Platform Availability

RSA Solution Brief

Entitlement enforcement for mobile applications

This mobile platform vendor included a wide variety of functionalities in their platform

and wanted to be able to turn features on or off depending on the customer’s runtime

license. In addition to needing RSA SHA1 signature verification in less than 30KB, like the

mobile phone customer, the platform OEM also needed SHA-1 hashing in less than 6KB.

Again, Crypto Kernel solved an issue that the internal development team was unable to

solve.

Intellectual property protection

This transportation systems manufacturer wanted to encrypt firmware on their equipment

to protect intellectual property (IP), reducing the risk of reverse engineering of the IP and

preventing device cloning. Crypto Kernel provided the manufacturer with a small

implementation of the AES algorithm to protect the IP on the equipment.

Secure information push

To provide Global Positioning System (GPS) customers with a better user experience, this

GPS device manufacturer wanted to provide the GPS satellite coordinate predictions to

devices more frequently. The prediction data was to be sent as an encrypted payload

when the device was docked, and so both DES and AES encryption needed to be

implemented in under 20KB—a goal met successfully by Crypto Kernel.

Narrowband communication security

This U.S. Department of Defense contractor needed to encrypt data packets from a device

sending information to a receiver via a narrow band communication channel. Because

this security concern was being addressed late in the project, there was less than 5KB

RAM available for the RSA® public key-based encryption APIs. In this case, Crypto

Kernel’s RSA algorithm was optimized for an ultra low-power 16-bit RISC microcontroller—

still meeting the code size constraints.

Digital rights management (DRM)

This consumer device manufacturer was implementing Windows® Media DRM 10 on a

networked music player but, because the device was not using a Microsoft® operating

system, Microsoft was unable to provide much support. The customer wanted small

implementations of RC4®, DES, AES, SHA-1, and RSA® (the algorithms used in Windows

Media DRM) in a small footprint. Crypto Kernel software provided a solution by optimizing

algorithms for the Blackfin processor.

Secure firmware updates

This General Packet Radio Service mobile modem manufacturer wanted to have boot-time

firmware decryption using AES, as well as verification and authentication of microcode

updates with their modem (which used a MIPS32 processor and a low-profile Real-Time

Operating System). Given the constraint of having less than 50KB of memory available,

the internal development team tried to meet the requirements using open source security

software, but was able to reduce the code size to only 100KB with unacceptably slow

performance. Also, the effort of trying to solve the security software concern was

distracting the development team from working on the core product functionality. Crypto

Kernel software solved this customer’s problem in a timely manner, allowing the

development team to refocus their efforts on core development needs.

RSA’s proven solutions help developers meet the challenges of implementing

cryptography in embedded environments. RSA is one of the most respected leaders and

innovators in information security with over 20,000 customers worldwide. A full

complement of professional assessment and customization services, developer support

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RSA Solution Brief

and market-leading products will help you deliver applications that inspire confidence in

your users.

RSA continues to innovate, providing the latest data security mechanisms and standards

through the support of RSA Laboratories, ensuring that you have the most efficient

technology available to secure embedded systems. RSA also continues to invest in third-

party validations of cryptography components through the National Institute for

Standards in Technology FIPS 140 Cryptographic Module Validation Program. RSA has a

deep understanding of the special needs of the embedded market and continues to

invest in highly customizable cryptographic components like Crypto Kernel to meet the

requirements of customers worldwide.

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Algorithms

RSA Solution Brief page 8

RSA Solution Brief

named curves

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RSA Solution Brief

supported standards

tls cipher suites

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EMC, EMC2, RSA, the RSA logo and BSAFE are registered trademarks or trademarks of EMC Corporation in the United

States and other countries. All other trademarks used herein are the property of their respective owners.

©2007-2011 EMC Corporation. All rights reserved. Published in the USA.

H11924 h9048-cryk-sb-1111

ABOUT RSA

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Combining business-critical controls in identity assurance, encryption & key

management, SIEM, Data Loss Prevention and Fraud Protection with industry leading

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generated. For more information, please visit www.RSA.com and www.EMC.com.

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