RECENT BLOG NEWS

The wolfSSL’s repo pull request #8897 adds significant OpenSSL compatibility layer enhancements across four key areas: RSA operations, big number mathematics, X.509 certificate extensions, and private key serialization.

RSA API Enhancements:

The PR introduces comprehensive RSA-PSS (Probabilistic Signature Scheme) support with enhanced OpenSSL compatibility. Key additions include:

• wolfSSL_EVP_PKEY_CTX_set_rsa_pss_saltlen() for configuring salt lengths
• wolfSSL_EVP_PKEY_CTX_set_rsa_mgf1_md() for setting MGF1 hash algorithms
• wolfSSL_EVP_PKEY_CTX_set_rsa_oaep_md() for RSA-OAEP padding configuration
• The existing wolfSSL_RSA_sign and wolfSSL_RSA_verify functions have been enhanced to support RSA-PSS with custom salt lengths and MGF1 hash types.
• Additional functions include wolfSSL_RSA_padding_add_PKCS1_PSS_mgf1() and wolfSSL_RSA_verify_PKCS1_PSS_mgf1() for advanced PSS padding operations with MGF1 support.

Bignum API Additions:

A new wolfSSL_BN_ucmp() function has been added that compares the absolute values of two WOLFSSL_BIGNUM structures. This function provides OpenSSL-compatible behavior identical to BN_ucmp(). The implementation uses internal duplication to avoid modifying const input parameters, making the implementation compliant with the API.

X.509 Extensions API Additions:

Two X.509 certificate extension handling functions have been added. The wolfSSL_X509v3_get_ext_by_NID() function searches for extensions by their Numeric Identifier (NID) within a stack of extensions, supporting iterative searching with a “lastpos” parameter. The wolfSSL_X509v3_get_ext() function retrieves extensions by index position from an extension stack. Both functions enable programmatic certificate extension processing for PKI applications, policy enforcement, and extension data extraction.

Private Key DER Output API Additions:

The new wolfSSL_i2d_PrivateKey_bio() function provides private key serialization to DER format through BIO objects. This function performs a two-pass operation to determine buffer size and encode the key.

These additions collectively enhance wolfSSL’s OpenSSL compatibility layer, providing essential functionality for RSA-PSS operations, mathematical computations, certificate processing, and key management operations required by modern cryptographic applications.

If you have questions about any of the above, please contact us at facts@wolfSSL.com or call us at +1 425 245 8247.

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Are you wondering what Microsoft’s roadmap for the IIS (Internet Information Services) webserver says about post-quantum cryptography? We’re not; read on to find out why.

Not everyone in the financial industry is old enough to remember what it was like to be in the trenches during the Y2K (Year 2000) era, but those that were around for it know that it was expensive both in dollar and human terms. Many dollars and man hours were spent converting years from two digits to four digits. In the end the endeavor to fix the Y2K bug was a victim of its own success. When January 1st, 2000 rolled around, everyone was fine and the financial system just went along all honky dory.

We here at wolfSSL are hoping for the same fate for Y2Q (Years To Quantum). Hopefully, when a cryptographically relevant quantum computer is finally built, everyone will have switched over to post-quantum algorithms. To ensure this is the case, we here at wolfSSL have been hard at work getting ahead of the curve.

That said, we feel your pain. We know that you’ve been conservatively using Microsoft products. Why wouldn’t you; who doesn’t trust Microsoft? Microsoft’s approach has been to prioritize stability over agility which makes sense for now. But you also know that there are timelines to move to post-quantum cryptography. So what are your options?

At wolfSSL, we are currently working on a product that is so new that it does not even have a name!! It will act as an alternative to Microsoft Windows SChannel Library. It will hook into the windows SSPI (Security Support Provider Interface). Why is this important? Because this is how network security is provided to the Windows IIS Webserver. Without even knowing it, IIS will seamlessly become quantum-safe when you pop in wolfSSL’s alternative to SChannel!

Let us know what you think of the concept around this new product. Are you interested in seeing the timeline accelerated and the priority raised? Let us know by reaching out to facts@wolfssl.com.

If you have questions about any of the above, please contact us at facts@wolfssl.com or call us at +1 425 245 8247.

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The latest release of wolfSSL 5.8.2 comes with key improvements for users of the wolfSSL sniffer.

Multi-Session Sniffer Support

The wolfSSL sniffer now supports decoding multiple TLS sessions, including those using session tickets and session resumption.

This enables more accurate decryption of real-world TLS traffic, where connections are commonly reused for performance.

New ssl_RemoveSession() API

This release also introduces a new API for targeted sniffer session cleanup:

int ssl_RemoveSession(const char* clientIp, int clientPort,
                      const char* serverIp, int serverPort,
                      char* error);

This allows for fine-grained control of cached sessions, helping reduce memory usage which can be integral especially when operating in high traffic environments.

If you have questions about any of the above, please contact us at facts@wolfssl.com or call us at +1 425 245 8247.

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At wolfSSL, we prioritize strong, modern cryptographic practices—especially for embedded systems where performance, code size, and reliability are critical. While TLS continues to be the standard for securing communications, many early protocol versions have been broken or deprecated due to serious security flaws. Understanding the history of these attacks and their mitigations helps clarify why wolfSSL supports TLS 1.2 and TLS 1.3 only, with hardened configurations and no legacy baggage.

Summary: Vulnerable Versions at a Glance

SSL 3.0 – Broken by Design (1996)

Attack: POODLE

• Exploits predictable padding in CBC mode.
• Allows a MITM to decrypt encrypted messages byte-by-byte.
• Requires protocol downgrade (common with fallback support in legacy clients).

Attack: Renegotiation

• Unpatched versions allow MITM data injection.
• Fixed by RFC 5746.

Mitigation:

• Disable SSL 3.0 entirely.
• No fix is possible within the protocol itself.

TLS 1.0 – Weak Encryption and Block Mode Flaws

Attack: BEAST

• Targets predictable IVs in CBC mode.
• Attacker uses JaveScript injection to decrypt HTTPS cookies via MITM.

Attack: CRIME

• Exploits TLS compression to infer secret data via length differences in compressed responses.

Attack: Renegotiation

• Unpatched versions allow MITM data injection.
• Fixed by RFC 5746.

Issue: RC4 Bias

• Long-known statistical biases in RC4 keystream make it vulnerable to ciphertext recovery.

Mitigations:

• TLS 1.1 introduced random IVs to mitigate BEAST.
• Disabling TLS compression and RC4 ciphers mitigates CRIME and RC4 bias.
• TLS 1.0 is officially deprecated by wolfSSL and not recommended for any deployments.

TLS 1.1 – Marginal Upgrade, Still Outdated

• Addressed BEAST with random IVs.
• Still lacked support for authenticated encryption (AEAD), forward secrecy by default, and encrypted handshake metadata.

Attack: Lucky 13

• Partial plaintext recovery through adaptive chosen ciphertext attacks when using CBC-mode ciphers.

Attack: Renegotiation

• Unpatched versions allow MITM data injection.
• Fixed by RFC 5746.

Mitigations:

• While safer than TLS 1.0, TLS 1.1 lacks modern protections.
• Use Encrypt-then-MAC (RFC7366) – default in wolfSSL.
• wolfSSL does not support TLS 1.1 by default and does not recommend enabling it unless required for backward compatibility.

TLS 1.2 – Secure When Properly Configured

TLS 1.2 remains widely used and secure when hardened. The vulnerabilities discovered were due to weak configurations or legacy cipher support—not flaws in the protocol itself.

Attack: FREAK

• Exploits fallback to 512-bit “export-grade” RSA keys.
• Attackers brute-force these weak keys to decrypt session data.

Attack: Logjam

• Similar concept to FREAK but targets Diffie-Hellman key exchange with weak 512-bit parameters.

Attack: DROWN

• Targets servers that share a certificate across both TLS and SSLv2.
• Exploits SSLv2 flaws to decrypt TLS data.

Attack: Lucky 13

• Partial plaintext recovery through adaptive chosen ciphertext attacks when using CBC-mode ciphers.

Attack: Renegotiation

• Unpatched versions allow MITM data injection.
• Fixed by RFC 5746.

Mitigations:

• Disable export cipher suites and SSLv2 support.
• Use strong ephemeral key exchange (e.g., ECDHE).
• Use Encrypt-then-MAC (RFC7366).
• Use AEAD ciphers (AES-GCM, ChaCha20-Poly1305).
• wolfSSL provides TLS 1.2 with modern defaults and no export cipher support.

TLS 1.3 – Minimal, Secure, and Efficient

TLS 1.3 removes legacy features that caused vulnerabilities in the past:

• No RC4, no CBC, no static RSA, no compression, no export ciphers.
• Forward secrecy is mandatory.
• Encrypts more of the handshake, preventing downgrade attacks and metadata leakage.
• Streamlined cipher suite negotiation.

Mitigations Built-In:

• TLS 1.3 was designed from the ground up to address all prior attack classes.
• wolfSSL’s TLS 1.3 implementation is FIPS 140-3 Ready and optimized for resource-constrained devices.

wolfSSL Recommendations

As a TLS library optimized for embedded systems, IoT, aerospace, and automotive, we encourage:

1. Use TLS 1.3 wherever possible for reduced code size and maximum security.
2. TLS 1.2 is acceptable when configured with strong ciphers and forward secrecy.
3. Disable legacy protocols (SSL 3.0, TLS 1.0, TLS 1.1) entirely.
4. Audit your build flags to avoid accidental inclusion of weak algorithms.

Conclusion

TLS has evolved from early, flawed implementations to strong, modern protocols that protect billions of connections daily. But only by disabling old versions and enforcing hardened configurations can systems stay secure. wolfSSL supports only TLS 1.2 and TLS 1.3, giving you confidence that your embedded or server deployments are resilient against both legacy and modern threats.

If you have questions about any of the above, please contact us at facts@wolfSSL.com or call us at +1 425 245 8247.

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