RECENT BLOG NEWS
The wolfSSL embedded SSL/TLS library supports lwIP, the light weight internet protocol implementation, out of the box. The user merely needs to define
WOLFSSL_LWIP or uncomment the line
/* #define WOLFSSL_LWIP */ in os_settings.h to use wolfSSL with lwIP.
The focus of lwIP is to reduce RAM usage while still providing a full TCP stack. That focus makes lwIP great for use in embedded systems, the same area where wolfSSL is an ideal match for SSL/TLS needs. An active community exists with contributor ports for many systems. Give it a try and let us know if you have any suggestions or questions.
For the latest news and releases of lwIP, you can visit the project homepage, here: http://savannah.nongnu.org/projects/lwip/
For more information, please contact email@example.com.
The CyaSSL embedded SSL library has had support for TLS 1.2 since version 1.1.0 in September of 2009 (over a year and a half ago). We realize that many people don’t know the difference between TLS 1.1 and TLS 1.2, and we wanted to give some quick highlights on the differences between these two protocol versions.
As stated in the TLS 1.1 and 1.2 protocol definitions (RFC 4346, RFC 5246), “The primary goal of the TLS protocol is to provide privacy and data integrity between two communicating applications.” TLS 1.2 is an improvement to the TLS 1.1 standard, but how exactly do they differ? What was changed in TLS 1.2 to warrant a new version of the protocol?
Listed below are the changes made in version 1.2 of the TLS protocol. TLS 1.2 support is slowly making it’s way into existing projects. CyaSSL fully supports SSL 3.0, TLS 1.0, TLS 1.1, and TLS 1.2.
A. TLS 1.2
This protocol was defined in RFC 5246 in August of 2008. Based on TLS 1.1, TLS 1.2 contains improved flexibility. One of the primary goals of the TLS 1.2 revision was to remove the protocol’s dependency on the MD5 and SHA-1 digest algorithms. The major differences include:
–The MD5/SHA-1 combination in the pseudorandom function (PRF) was replaced with cipher-suite-specified PRFs.
–The MD5/SHA-1 combination in the digitally-signed element was replaced with a single hash. Signed elements include a field explicitly specifying the hash algorithm used.
–There was substantial cleanup to the client’s and server’s ability to specify which hash and signature algorithms they will accept.
–Addition of support for authenticated encryption with additional data modes.
–TLS Extensions definition and AES Cipher Suites were merged in.
–Tighter checking of EncryptedPreMasterSecret version numbers.
–Many of the requirements were tightened
–Verify_data length depends on the cipher suite
–Description of Bleichenbacher/Dlima attack defenses cleaned up.
–Alerts must be sent in many cases
–After a certificate_request, if no certificates are available, clients now MUST send an empty certificate list.
–TLS_RSA_WITH_AES_128_CBC_SHA is now the mandatory to implement cipher suite.
–Added HMAC-SHA256 cipher suites.
–Removed IDEA and DES cipher suites. They are now deprecated.
To read more about TLS 1.2, you can find the specification (RFC 5246), here: http://tools.ietf.org/html/rfc5246.
B. Goals of the TLS Protocol
–Cryptographic security: TLS should be used to establish a secure connection between two parties.
–Interoperability: Independent programmers should be able to develop applications utilizing TLS that can successfully exchange cryptographic parameters without knowledge of one another’s code.
–Extensibility: TLS seeks to provide a framework into which new public key and bulk encryption methods can be incorporated as necessary. This will also accomplish two sub-goals: preventing the need to create a new protocol (and risking the introduction of possible new weaknesses) and avoiding the need to implement an entire new security library.
–Relative efficiency: Cryptographic operations tend to be highly CPU intensive, particularly public key operations. For this reason, the TLS protocol has incorporated an optional session caching scheme to reduce the number of connections that need to be established from scratch. Additionally, care has been taken to reduce network activity.
If you would like to read more about SSL or TLS, here are several resources that might be helpful:
TLS – Wikipedia (http://en.wikipedia.org/wiki/Transport_Layer_Security)
TLS 1.0 (RFC 0000): http://tools.ietf.org/html/rfc2246
TLS 1.1 (RFC 0000): http://tools.ietf.org/html/rfc4346
TLS 1.2 (RFC 0000): http://tools.ietf.org/html/rfc5246
As always, if you have any questions or would like more information about the CyaSSL embedded SSL library or the yaSSL Embedded Web Server, please contact firstname.lastname@example.org.
If you`ve been keeping an eye on our blog lately, you`ve probably noticed our series of blog posts about new features and changes we have made in wolfSSL 2.0. If you`re as excited as we are about our next release, we hope you enjoy the following video link:
Release Candidate 1 for wolfSSL 2.0 is available for download from our “Download” page (link). We invite you to download it and take it for a spin. Let us know about any bugs or problems you run into, and if you have any suggestions to make our 2.0 release more robust we`d love to hear them. Please send any comments or questions to email@example.com.
Here`s the third part in a four part series giving a more detailed report on some of the new features present in the recent wolfSSL release.
• Runtime hooks for logging. The wolfSSL embedded SSL library has had the ability to do logging when debug is enabled for some time. Now, logging callback functions can be registered at runtime to provide some more flexibility with how logging is done. The logging callback can be registered with:
int wolfSSL_SetLoggingCb(wolfSSL_Logging_cb log_function);
typedef void (*wolfSSL_Logging_cb)(const int logLevel,
const char *const logMessage);
The log levels can be found in logging.h and the implementation is in logging.c. By default, wolfSSL logs to stderr with fprintf.
• More informative error codes. With the new logging facility an effort was made to change generic errors (-1) to more informative ones. This should aid in the debugging of SSL problems in general and particularly during the SSL handshake.
• More informative logging messages. As with the above feature, an effort was made to have more descriptive logging messages both in error cases and for informational output. These should aid debugging and tracking as well.
• EDH on server side. A wolfSSL server can now do Ephemeral Diffie-Hellman. No build changes are needed to add this feature. Though an application will have to register the ephemeral group parameters on the server side to enable the EDH cipher suites. A new API can be used to do this:
int wolfSSL_SetTmpDH(SSL* ssl, unsigned char* p,int pSz,unsigned char* g,int gSz);
The example server and echoserver use this function from SetDH().
• More robust server downgrade. Both wolfSSL clients and servers now have robust version downgrade capability. If a specific version method is used on either side then only that version will be negotiated or an error will be returned. A client that uses TLSv1 and tries to connect to a SSLv3 only server will fail, likewise connecting to a TLSv1.1 will fail as well. On the other hand, a client that uses SSLv23 (use the highest version supported and downgrade to SSLv3 if needed) will connect to a server running SSLv3 – TLSv1.2. The only version it can`t connect to is SSLv2 which has been insecure for years. Similarly, a server using SSLv23 can handle clients from SSLv3 – TLSv1.2. A wolfSSL server can`t accept a connection from SSLv2 because no security is provided.
We wanted to let our followers know that we`re in the process of porting wolfSSL to FreeRTOS/OpenRTOS. FreeRTOS is a real-time operating system for embedded devices which is designed to be small and simple. Currently, it officially supports 27 architectures and is downloaded over 77 thousand times every year.
Like wolfSSL, FreeRTOS is portable, open source and royalty free. OpenRTOS has an identical code base to FreeRTOS except it offers a commercial license for those projects which would rather not abide by the terms of the GPL.
For a full list of features in FreeRTOS/OpenRTOS, and to learn more about the project in general, visit the FreeRTOS website at http://www.freertos.org/.
If you would like to use wolfSSL with FreeRTOS, or have any questions about our port, please let us know at firstname.lastname@example.org.
We want to announce that the wolfSSL embedded SSL library has been ported to the popular KLone Web Application Framework and is now available as a build option in KLone 2.4.0!
KLone is a multi-platform web application development framework which is targeted specifically for embedded systems and appliances. It not only includes a full-featured web server, but also an SDK for creating websites with both static and dynamic content. KLone combines the web server application (HTTP, HTTPS) together with content and configuration into one single executable file. Because it`s optimized to run in embedded environments, it maintains a small application footprint and offers fast execution speeds.
We think that KLone and wolfSSL fit together very well. Both are optimized for embedded environments, are dual licensed under the GPLv2 and commercial licensing, are royalty free, and have awesome development teams behind them. Initial tests with KLone and wolfSSL resulted in a 20X disk/flash footprint decrease and a 3X performance gain over the comparable OpenSSL+libcrypto combo.
To build KLone with wolfSSL, follow the instructions provided with the KLone download located in the README.wolfSSL file, or download the KLone “Crypto” example application and follow the included instructions. More information can be found at the following links:
Here`s the second part in a four part series giving a more detailed report of some of the new features present in the recent wolfSSL release.
• UID parsing for x509. Certificates that contain UIDs now have the UID saved for retrieval by wolfSSL. No additional function calls are needed as the UID is contained in the subject or issuer name line and processed like email as part of the Common Name (CN). The UID is prefixed with /UID as the identifier.
• SHA-256 Certificate Signatures. Some certificates are showing up in the wild with SHA-256 certificates though it`s still very unusual. To stay ahead of the curve, wolfSSL now supports certificate and signature verification with SHA-256. No action is needed by the user as this is all done internally.
• Client and server can send certificate chains. Previously, wolfSSL would only send the actual or “bottom” certificate of a chain and rely on the other side to have the rest of the chain available for processing. Now, the user can load all or part of a certificate chain using the function call:
int SSL_CTX_use_certificate_chain_file(SSL_CTX *ctx, const char *file);
file must be in PEM format and must be sorted starting with the subject`s certificate (the actual client or server cert), followed by any intermediate certificates and ending (optionally) at the root “top” CA. The example server now uses this functionality.
• CA loading can now parse multiple certificates per file. wolfSSL is able to load several CAs for verification purposes from one file using the function call:
int SSL_CTX_load_verify_locations(SSL_CTX *ctx, const char *CAfile, const char *CApath);
by passing in a CAfile in PEM format with as many certs as possible. This is useful when a client needs to load several root CAs at startup and makes initialization easier. It also makes it easier to port into tools that expect to be able to use a single file for CAs.
• Dynamic memory runtime hooks. wolfSSL has had a memory abstraction layer for quite some time, allowing the user to take control of dynamic memory handling. This new feature allows the ability to register the memory override functions at runtime instead of compile time. cyassl_memory.h is the header for this functionality and the user can call:
int wolfSSL_SetAllocators(wolfSSL_Malloc_cb malloc_function,
to setup the memory functions. Please see the header for the callback prototypes and cyassl_memory.c for the implementation.
Hi! In the last 9 months, we’ve made great strides in improving our documentation. However, we recognize that more work needs to be done. We primarily want to make it easy for someone who is new to SSL to get started and be productive and comfortable with the technology.
One of the documents that we came out with is a general purpose SSL tutorial targeted to programmers that are getting started with CyaSSL.
Our goal is to continue to make incremental improvement in the documentation, so please give us your feedback! Let us know where we are lacking and what needs to be better explained. We’ll make the changes, just send us an email with your thoughts on how we can improve to email@example.com.
Here`s a more detailed report on some of the new features that are in the recent wolfSSL 2.0 release. wolfSSL 2.0 RC1 is available for download from our Downloads page.
* SHA-256 cipher suites are now supported. The new suites include:
No action is needed to include these suites, they`re in by default.
* Root certificate verification has been added. wolfSSL used to require all certificates in the chain to be trusted in order to do a verification. Now, only the top or root certificate of the chain is required to be loaded as a trusted certificate in order to properly verify the chain.
* PKCS #8 private key encryption. wolfSSL now support PKCS #8 private encrypted keys. Supported formats include PKCS #5 version 1 – version 2 and PKCS #12. Types of encryption available include DES, 3DES, RC4, and AES.
* Serial number retrieval for x509. A serial number of any length can now be extracted with wolfSSL using the extension function:
int wolfSSL_X509_get_serial_number(X509* x509, byte* buffer, int* inOutSz)
buffer will be written to with at most *inOutSz bytes on input. After the call, if successful (return of 0), *inOutSz will hold the actual number of bytes written to buffer. A full example is included cyassl_test.h.
* PBKDF2 and PKCS #12 PBKDF. wolfSSL used to only support password based key derivation function 1. Now it additionally support version 2 and the PBKDF version from PKCS #12. Use is the same as the original and the function prototypes look like:
int PBKDF2(byte* output, const byte* passwd, int pLen, const byte* salt, int sLen, int iterations, int kLen, int hashType);
int PKCS12_PBKDF(byte* output, const byte* passwd, int pLen, const byte* salt, int sLen, int iterations, int kLen, int hashType, int purpose);
output contains the derived key, passwd holds the user password of length pLen, salt holds the salt input of length sLen, iterations is the number of iterations to perform, kLen is the desired derived key length, and hashType is the hash to use which can be MD5, SHA1, or SHA2.
The yaSSL team is live from ESC Silicon Valley – located at booth 2322. This morning and afternoon has been bustling with activity after attendees lined up for the free tote bag giveaway. If you’re at ESC 2011, stop by our booth to visit. We’ll be talking about how you can add SSL/TLS to your embedded application or device through our wolfSSL library as well as our yaSSL Embedded Web Server.
We hope to see you here!
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