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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