RECENT BLOG NEWS
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!
wolfSSL 2.0.0 Release Candidate 1 is now available for download on our website. The release is chunk full of new features including:
– SHA-256 cipher suites
– Root Certificate Verification (instead of needing all certs in the chain)
– PKCS #8 private key encryption (supports PKCS #5 v1-v2 and PKCS #12)
– Serial number retrieval for x509
– PBKDF2 and PKCS #12 PBKDF
– UID parsing for x509
– SHA-256 certificate signatures
– Client and server can send chains (SSL_CTX_use_certificate_chain_file)
– CA loading can now parse multiple certificates per file
– Dynamic memory runtime hooks
– Runtime hooks for logging
– EDH on server side
– More informative error codes
– More informative logging messages
– Version downgrade more robust (use SSL_v23*)
– Shared build only by default through ./configure
– Compiler visibility is now used, internal functions not polluting namespace
– Single Makefile, no recursion, for faster and simpler building
– Turn on all warnings possible build option, warning fixes
Stay tuned for a few posts this week giving more details about all the new features.
Because of all the new features and the multiple OS, compiler, feature-set options that wolfSSL allows, there may be some configuration fixes needed. Please send any comments or questions to firstname.lastname@example.org.
- December 2022 (2)
- November 2022 (11)
- October 2022 (9)
- September 2022 (7)
- August 2022 (12)
- July 2022 (11)
- June 2022 (15)
- May 2022 (11)
- April 2022 (14)
- March 2022 (12)
- February 2022 (21)
- January 2022 (13)
- December 2021 (13)
- November 2021 (29)
- October 2021 (15)
- September 2021 (15)
- August 2021 (13)
- July 2021 (21)
- June 2021 (19)
- May 2021 (12)
- April 2021 (12)
- March 2021 (27)
- February 2021 (29)
- January 2021 (22)
- December 2020 (21)
- November 2020 (14)
- October 2020 (7)
- September 2020 (22)
- August 2020 (11)
- July 2020 (8)
- June 2020 (14)
- May 2020 (15)
- April 2020 (14)
- March 2020 (4)
- February 2020 (24)
- January 2020 (18)
- December 2019 (7)
- November 2019 (16)
- October 2019 (14)
- September 2019 (24)
- August 2019 (21)
- July 2019 (8)
- June 2019 (13)
- May 2019 (35)
- April 2019 (31)
- March 2019 (20)
- February 2019 (10)
- January 2019 (16)
- December 2018 (24)
- November 2018 (10)
- October 2018 (18)
- September 2018 (18)
- August 2018 (8)
- July 2018 (15)
- June 2018 (29)
- May 2018 (15)
- April 2018 (11)
- March 2018 (19)
- February 2018 (6)
- January 2018 (11)
- December 2017 (5)
- November 2017 (12)
- October 2017 (7)
- September 2017 (8)
- August 2017 (6)
- July 2017 (11)
- June 2017 (8)
- May 2017 (10)
- April 2017 (5)
- March 2017 (7)
- February 2017 (1)
- January 2017 (8)
- December 2016 (3)
- November 2016 (2)
- October 2016 (18)
- September 2016 (8)
- August 2016 (5)
- July 2016 (4)
- June 2016 (10)
- May 2016 (4)
- April 2016 (5)
- March 2016 (4)
- February 2016 (12)
- January 2016 (6)
- December 2015 (4)
- November 2015 (6)
- October 2015 (6)
- September 2015 (5)
- August 2015 (8)
- July 2015 (7)
- June 2015 (9)
- May 2015 (1)
- April 2015 (4)
- March 2015 (13)
- January 2015 (6)
- December 2014 (7)
- November 2014 (3)
- October 2014 (2)
- September 2014 (11)
- August 2014 (6)
- July 2014 (9)
- June 2014 (11)
- May 2014 (11)
- April 2014 (9)
- March 2014 (3)
- February 2014 (3)
- January 2014 (5)
- December 2013 (9)
- November 2013 (4)
- October 2013 (7)
- September 2013 (3)
- August 2013 (9)
- July 2013 (7)
- June 2013 (4)
- May 2013 (8)
- April 2013 (4)
- March 2013 (2)
- February 2013 (3)
- January 2013 (9)
- December 2012 (13)
- November 2012 (5)
- October 2012 (7)
- September 2012 (4)
- August 2012 (6)
- July 2012 (4)
- June 2012 (3)
- May 2012 (5)
- April 2012 (7)
- March 2012 (2)
- February 2012 (5)
- January 2012 (7)
- December 2011 (5)
- November 2011 (7)
- October 2011 (6)
- September 2011 (6)
- August 2011 (5)
- July 2011 (2)
- June 2011 (8)
- May 2011 (12)
- April 2011 (4)
- March 2011 (12)
- February 2011 (8)
- January 2011 (13)
- December 2010 (17)
- November 2010 (12)
- October 2010 (14)
- September 2010 (11)
- August 2010 (20)
- July 2010 (14)
- June 2010 (7)
- May 2010 (1)
- January 2010 (2)
- November 2009 (2)
- October 2009 (1)
- September 2009 (1)
- May 2009 (1)
- February 2009 (1)
- January 2009 (1)
- December 2008 (1)