RECENT BLOG NEWS
Differences between TLS 1.2 and TLS 1.3 (#TLS13)
With the release of TLS 1.3, there are promises of enhanced security and speed. But how exactly do the changes from TLS 1.2 to TLS 1.3 cause these improvements? The following is a list of differences between TLS 1.2 and 1.3 that shows how the improvements are achieved.
wolfSSL is among the first libraries to support TLS 1.3. Below are the major differences between TLS 1.2 and TLS 1.3
TLS 1.3
This protocol is defined in Draft 28. TLS 1.3 contains improved security and speed. The major differences include:
• The list of supported symmetric algorithms has been pruned of all legacy algorithms. The remaining algorithms all use Authenticated Encryption with Associated Data (AEAD) algorithms.
• A zero-RTT (0-RTT) mode was added, saving a round-trip at connection setup for some application data at the cost of certain security properties.
• Static RSA and Diffie-Hellman cipher suites have been removed; all public-key based key exchange mechanisms now provide forward secrecy.
• All handshake messages after the ServerHello are now encrypted.
• Key derivation functions have been re-designed, with the HMAC-based Extract-and-Expand Key Derivation Function (HKDF) being used as a primitive.
• The handshake state machine has been restructured to be more consistent and remove superfluous messages.
• ECC is now in the base spec and includes new signature algorithms. Point format negotiation has been removed in favor of single point format for each curve.
• Compression, custom DHE groups, and DSA have been removed, RSA padding now uses PSS.
• TLS 1.2 version negotiation verification mechanism was deprecated in favor of a version list in an extension.
• Session resumption with and without server-side state and the PSK-based ciphersuites of earlier versions of TLS have been replaced by a single new PSK exchange.
Internet Draft: https://tools.ietf.org/html/draft-ietf-tls-tls13-28
Resources:
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)
SSL versus TLS – What`s the Difference? (http://luxsci.com/blog/ssl-versus-tls-whats-the-difference.html)
Differences Between SSL and TLS Protocol Versions (http://www.wolfssl.com/differences-between-ssl-and-tls-protocol-versions/)
Cisco – SSL: Foundation for Web Security (http://www.cisco.com/web/about/ac123/ac147/archived_issues/ipj_1-1/ssl.html)
What is a Block Cipher?
A block cipher is an encryption method that applies a deterministic algorithm along with a symmetric key to encrypt a block of text, rather than encrypting one bit at a time as in stream ciphers. For example, a common block cipher, AES, encrypts 128 bit blocks with a key of predetermined length: 128, 192, or 256 bits. Block ciphers are pseudorandom permutation (PRP) families that operate on the fixed size block of bits. PRPs are functions that cannot be differentiated from completely random permutations and thus, are considered reliable, until proven unreliable.
Block cipher modes of operation have been developed to eliminate the chance of encrypting identical blocks of text the same way, the ciphertext formed from the previous encrypted block is applied to the next block. A block of bits called an initialization vector (IV) is also used by modes of operation to ensure ciphertexts remain distinct even when the same plaintext message is encrypted a number of times.
Some of the various modes of operation for block ciphers include CBC (cipher block chaining), CFB (cipher feedback), CTR (counter), and GCM (Galois/Counter Mode), among others. Above is an example of CBC mode.
Where an IV is crossed with the initial plaintext block and the encryption algorithm is completed with a given key and the ciphertext is then outputted. This resultant cipher text is then used in place of the IV in subsequent plaintext blocks.
For information on the block ciphers that are implemented in wolfSSL or to learn more about the wolfSSL lightweight, embedded SSL library, go to wolfssl.com or contact us at facts@wolfssl.com.
References
[1] Pseudorandom permutation. (2014, November 23). In Wikipedia, The Free Encyclopedia.
Retrieved 22:06, December 18, 2014, from
http://en.wikipedia.org/w/index.php?title=Pseudorandom_permutation&oldid=635108728.
Most recent version:
https://en.wikipedia.org/wiki/Pseudorandom_permutation
[2] Margaret Rouse. (2014). Block Cipher [Online]. Available URL:
http://searchsecurity.techtarget.com/definition/block-cipher.
[3] Block cipher mode of operation. (2014, December 12). In Wikipedia, The Free
Encyclopedia. Retrieved 22:17, December 18, 2014, from
http://en.wikipedia.org/w/index.php?title=Block_cipher_mode_of_operation&oldid=637837298
Most recent version:
https://en.wikipedia.org/wiki/Block_cipher_mode_of_operation
[4] Wikimedia. (2014). Available URL:
http://upload.wikimedia.org/wikipedia/commons/d/d3/Cbc_encryption.png.
A Comparison of Differences in TLS 1.1 and TLS 1.2
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 to both version 1.1 and 1.2 of the TLS protocol. TLS 1.2 support is making headway in more and more new projects today. The wolfSSL embedded SSL/TLS library fully supports SSL 3.0 (disabled at runtime by default), TLS 1.0, TLS 1.1, TLS 1.2, and TLS 1.3.
A. TLS 1.1
This protocol was defined in RFC 4346 in April of 2006, and is an update to TLS 1.0. The major changes are:
– The Implicit Initialization Vector (IV) is replaced with an explicit IV to protect against Cipher block chaining (CBC) attacks.
– Handling of padded errors is changed to use the bad_record_mac alert rather than the decryption_failed alert to protect against CBC attacks.
– IANA registries are defined for protocol parameters
– Premature closes no longer cause a session to be non-resumable.
RFC 4346: http://tools.ietf.org/html/rfc4346#section-1.1
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.
RFC 5246: http://tools.ietf.org/html/rfc5246
C. 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.
Resources:
If you would like to read more about SSL or TLS, here are several resources that might be helpful:
wolfSSL Manual (https://www.wolfssl.com/wolfSSL/Docs-wolfssl-manual-toc.html)
TLS – Wikipedia (http://en.wikipedia.org/wiki/Transport_Layer_Security)
SSL vs TLS – What`s the Difference? (http://luxsci.com/blog/ssl-versus-tls-whats-the-difference.html)
Differences between SSL and TLS versions: (https://www.wolfssl.com/differences-between-ssl-and-tls-protocol-versions/)
Cisco – SSL: Foundation for Web Security (http://www.cisco.com/web/about/ac123/ac147/archived_issues/ipj_1-1/ssl.html)
If you have any questions or would like to talk to the wolfSSL team about more information, please contact facts@wolfssl.com.
Differences between SSL and TLS Protocol Versions (#TLS13)
wolfSSL supports all three of these ciphers to best suit your needs and requirements. Below you will find the major differences between the different protocol versions.
SSL 3.0
This protocol was released in 1996, but first began with the creation of SSL 1.0 developed by Netscape. Version 1.0 wasn`t released, and version 2.0 had a number of security flaws, thus leading to the release of SSL 3.0. Some major improvements of SSL 3.0 over SSL 2.0 are:
– Separation of the transport of data from the message layer
– Use of a full 128 bits of keying material even when using the Export cipher
– Ability of the client and server to send chains of certificates, thus allowing organizations to use certificate hierarchy which is more than two certificates deep.
– Implementing a generalized key exchange protocol, allowing Diffie-Hellman and Fortezza key exchanges as well as non-RSA certificates.
– Allowing for record compression and decompression
– Ability to fall back to SSL 2.0 when a 2.0 client is encountered
Netscape`s Original SSL 3.0 Draft: http://www.mozilla.org/projects/security/pki/nss/ssl/draft302.txt
Comparison of SSLv2 and SSLv3: http://stason.org/TULARC/security/ssl-talk/4-11-What-is-the-difference-between-SSL-2-0-and-3-0.html
TLS 1.0
This protocol was first defined in RFC 2246 in January of 1999. This was an upgrade from SSL 3.0 and the differences were not dramatic, but they are significant enough that SSL 3.0 and TLS 1.0 don`t interoperate. Some of the major differences between SSL 3.0 and TLS 1.0 are:
– Key derivation functions are different
– MACs are different – SSL 3.0 uses a modification of an early HMAC while TLS 1.0 uses HMAC.
– The Finished messages are different
– TLS has more alerts
– TLS requires DSS/DH support
RFC 2246: http://tools.ietf.org/html/rfc2246
TLS 1.1
This protocol was defined in RFC 4346 in April of 2006, and is an update to TLS 1.0. The major changes are:
– The Implicit Initialization Vector (IV) is replaced with an explicit IV to protect against Cipher block chaining (CBC) attacks.
– Handling of padded errors is changed to use the bad_record_mac alert rather than the decryption_failed alert to protect against CBC attacks.
– IANA registries are defined for protocol parameters
– Premature closes no longer cause a session to be non-resumable.
RFC 4346: http://tools.ietf.org/html/rfc4346#section-1.1
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. 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.
RFC 5246: http://tools.ietf.org/html/rfc5246
TLS 1.3
This protocol is currently being revised, and is in its 28th draft. The major differences from TLS 1.2 include:
– The list of supported symmetric algorithms has been pruned of all legacy algorithms. The remaining algorithms all use Authenticated Encryption with Associated Data (AEAD) algorithms.
– A zero-RTT (0-RTT) mode was added, saving a round-trip at connection setup for some application data at the cost of certain security properties.
– Static RSA and Diffie-Hellman cipher suites have been removed; all public-key based key exchange mechanisms now provide forward secrecy.
– All handshake messages after the ServerHello are now encrypted.
– Key derivation functions have been re-designed, with the HMAC-based Extract-and-Expand Key Derivation Function (HKDF) being used as a primitive.
– The handshake state machine has been restructured to be more consistent and remove superfluous messages.
– ECC is now in the base spec and includes new signature algorithms. Point format negotiation has been removed in favor of single point format for each curve.
– Compression, custom DHE groups, and DSA have been removed, RSA padding now uses PSS.
– TLS 1.2 version negotiation verification mechanism was deprecated in favor of a version list in an extension.
– Session resumption with and without server-side state and the PSK-based ciphersuites of earlier versions of TLS have been replaced by a single new PSK exchange.
Internet draft 28: https://tools.ietf.org/html/draft-ietf-tls-tls13-28
Resources:
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)
SSL versus TLS – What`s the Difference? (http://luxsci.com/blog/ssl-versus-tls-whats-the-difference.html)
Cisco – SSL: Foundation for Web Security (http://www.cisco.com/web/about/ac123/ac147/archived_issues/ipj_1-1/ssl.html)
As always, if you have any questions or would like to talk to the wolfSSL team about more information, please contact facts@wolfssl.com.
TLS 1.3 Draft 28 Support in wolfSSL (#TLS13)
As you may have noticed, we released version 3.15.0 of wolfSSL. One of the features in this release was TLS 1.3 Draft 28 support! Draft 28 is the latest version of the TLS 1.3 specification, and can be enabled in wolfSSL at configure time by using the “–enable-tls13” build option:
--enable-tls13 Enable wolfSSL TLS v1.3 (default: disabled)
If you would still like (or need) to support older drafts of TLS 1.3, we still include support for Drafts 18, 22, 23, and 26. Each of these have their own respective configure option:
--enable-tls13-draft18 Enable wolfSSL TLS v1.3 Draft 18 (default: disabled) --enable-tls13-draft22 Enable wolfSSL TLS v1.3 Draft 22 (default: disabled) --enable-tls13-draft23 Enable wolfSSL TLS v1.3 Draft 23 (default: disabled) --enable-tls13-draft26 Enable wolfSSL TLS v1.3 Draft 26 (default: disabled)
For those interested in what has been changing with new drafts of TLS 1.3, you can view the Change Log in the TLS 1.3 RFC here. The big difference between Draft 27 and Draft 28 was the addition of a section on exposure of PSK identities. If you would like to learn more about wolfSSL’s support for TLS 1.3 and how to use it in your application, please visit our page about it today! We also recently put out a blog post series talking about the performance of TLS 1.3 in wolfSSL:
Part 1 (TLS 1.3 Performance – Resumption)
Part 2 (TLS 1.3 Performance – Full Handshake)
Part 3 (TLS 1.3 Performance – Pre-Shared Key (PSK))
Part 4 (TLS 1.3 Performance – Server Pre-Generation)
Part 5 (TLS 1.3 Performance – Client-Server Authentication)
Part 6 (TLS 1.3 Performance – Throughput)
Performance Comparison: TLS 1.3 in wolfSSL and OpenSSL
If you would like more information about wolfSSL’s support for TLS 1.3 or help on using it in your application, contact us at facts@wolfssl.com.
wolfSSL and ROHNP
wolfSSL is one of over a dozen vendors mentioned in the recent Technical Advisory "ROHNP" by author Ryan Keegan. Versions of wolfSSL prior to 3.15.3 were vulnerable to a Key Extraction Side Channel Attack. wolfSSL v3.15.3 which is protected against these attacks and has other improvements is available for download now on our website.
Only wolfSSL users with long term ECDSA private keys using our fastmath or normal math libraries on systems where attackers can get access to the machine using the ECDSA key need to update. An attacker gaining access to the system could mount a memory cache side channel attack that could recover the key within a few thousand signatures. wolfSSL users that are not using ECDSA private keys, that are using the single precision math library, or that are using ECDSA offloading do not need to update. An update is still recommended however, as it is typically best to run the most up-to-date software versions.
Please contact support@wolfssl.com with any questions.
Link to advisory: https://www.nccgroup.trust/us/our-research/technical-advisory-return-of-the-hidden-number-problem/
Link to vulnerability database entry: CVE-2018-12436
Link to download page with most recent version: https://www.wolfssl.com/download/
wolfCrypt v4.0 FIPS with AES-NI
wolfSSL will be releasing wolfCrypt v4.0 FIPS with an expanded security boundary. We have added many algorithms to the boundary. We have also tested the code using AES-NI with Linux and Windows 10.
Intel added a set of instructions for accelerating AES processing including performing AES-GCM’s GHASH. Also available are accelerations to SHA-1, SHA-2, and SHA-3 hashing using the AVX instruction sets. Our implementations use algorithmically generated accelerated assembly code to get the job done fast.
For more information about wolfCrypt v4.0 FIPS, please send a message to fips@wolfssl.com. For more information about wolfSSL in general, including TLSv1.3 support, send a message to facts@wolfssl.com.
wolfCrypt v4.0 FIPS with Key Generation and RDSEED
wolfSSL will be releasing wolfCrypt v4.0 FIPS with an expanded security boundary. We have added many algorithms to the boundary, including Key Generation.
wolfCrypt v4.0 FIPS can generate keys for use with RSA and ECDSA signing. It can also do the perform the ECDHE and DHE key agreement schemes. We have also self-affirmed wolfCrypt for HKDF as a key-derivation function.
To use wolfCrypt key generation in a FIPS approved manner, you must build wolfCrypt with the Intel RDSEED feature enabled. If you do not have RDSEED available, you may use your own seeding method but it must meet the NIST SP 800-90B requirements.
For more information about wolfCrypt v4.0 FIPS, please send a message to fips@wolfssl.com. For more information about wolfSSL in general, including TLSv1.3 support, send a message to facts@wolfssl.com.
SCP with wolfSSH
We have been hard at work adding server support for SCP to wolfSSH and it will be available in the next release of wolfSSH, version 1.3.0.
If you have an embedded device and want to securely upload a new firmware image to it or download a log file with the convenience of a copy command, wolfSSH has you covered. Our server API keeps it simple to receive or send files when a client connects using ciphers found in our lightweight crypto library, wolfCrypt.
If you are interested in FIPS, wolfSSH compiles against wolfCrypt and can use the wolfCrypt FIPS library. For more information about FIPS, contact fips@wolfssl.com and we can discuss your requirements and FIPS testing.
For more information about wolfSSH please contact facts@wolfssl.com.
wolfSSL Release 3.15.0
wolfSSL is proud to announce release v3.15.0 of our wolfSSL embedded TLS library. Among the many additions are:
- Support for wolfCrypt FIPS on SGX
- Support for TLS 1.3 Draft versions
- Single Precision assembly code added for ARM and 64-bit ARM to enhance performance
- Improved performance for Single Precision maths on 32-bit
- Expanded OpenSSL compatibility layer
We have added Intel SGX as an operating environment for our wolfCrypt FIPS library. You can take advantage of running the wolfCrypt code in a secure enclave. For more information, contact fips@wolfssl.com.
With the finalization of TLS 1.3 on the horizon, we add incremental support for the drafts of the protocol. wolfSSL is current through draft 28 of the specification.
We are committed to supporting TLS 1.3 on embedded platforms, and we want to squeeze the most performance out of the chips for public key algorithms. After great success with the Intel assembly performance increases, we have added ARM assembly single-precision math support for RSA, ECC, and DHE.
To make porting existing projects over to wolfSSL, we have our OpenSSL compatibility layer. We are always expanding it. This release includes a large set of APIs to our support.
For more information, please contact facts@wolfssl.com. You can see the full change log in the source archive from our website at www.wolfssl.com or at our GitHub repository.
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