Pros of OpenSSL

• Wider adoption and community support
• More comprehensive feature set and broader protocol support
• Extensive documentation and resources available

Cons of OpenSSL

• Larger codebase, potentially more complex to maintain
• Historical security vulnerabilities due to legacy code
• Slower release cycle for updates and patches

Code Comparison

OpenSSL:

EVP_PKEY *pkey = EVP_PKEY_new();
EVP_PKEY_assign_RSA(pkey, rsa);
X509 *x509 = X509_new();
X509_set_pubkey(x509, pkey);

BoringSSL:

bssl::UniquePtr<EVP_PKEY> pkey(EVP_PKEY_new());
EVP_PKEY_assign_RSA(pkey.get(), rsa);
bssl::UniquePtr<X509> x509(X509_new());
X509_set_pubkey(x509.get(), pkey.get());

The code snippets demonstrate key and certificate handling. BoringSSL uses smart pointers for better memory management, while OpenSSL relies on manual resource handling.

BoringSSL, developed by Google, focuses on simplicity and security for modern applications. It removes legacy code and APIs, resulting in a smaller, more maintainable codebase. However, it may lack some features and compatibility with older systems compared to OpenSSL.

OpenSSL remains the more widely used option, offering broader compatibility and a more extensive feature set. It's suitable for a wide range of applications but may require more careful handling of its complexities and legacy components.

Pros of LibreSSL

• More focused on security and simplicity, with a cleaner codebase
• Better compatibility with OpenSSL, making it easier to adopt in existing projects
• Regular security audits and updates

Cons of LibreSSL

• Smaller development community compared to BoringSSL
• Less frequent updates and potentially slower adoption of new features
• May lack some performance optimizations present in BoringSSL

Code Comparison

BoringSSL (error handling):

if (ERR_peek_error() != 0) {
  // Handle error
  ERR_clear_error();
}

LibreSSL (error handling):

unsigned long err;
while ((err = ERR_get_error()) != 0) {
  // Handle error
}

Both libraries aim to provide secure and efficient cryptographic implementations, but they have different focuses. BoringSSL is tailored for Google's needs and emphasizes performance, while LibreSSL prioritizes security and OpenSSL compatibility. The code comparison shows slight differences in error handling approaches, with LibreSSL using a more traditional OpenSSL-like method.

Pros of wolfSSL

• Smaller footprint and better suited for embedded systems
• More extensive support for various cryptographic algorithms
• Offers both open-source and commercial licensing options

Cons of wolfSSL

• Less widely adopted compared to BoringSSL
• May have fewer resources and community support
• Potentially slower development cycle for new features

Code Comparison

wolfSSL:

int wolfSSL_Init(void) {
    WOLFSSL_ENTER("wolfSSL_Init");
    if (initRefCount == 0) {
        if (InitMutex() != 0)
            return WOLFSSL_FAILURE;
        if (InitRng() != 0)
            return WOLFSSL_FAILURE;
    }
    initRefCount++;
    return WOLFSSL_SUCCESS;
}

BoringSSL:

int CRYPTO_library_init(void) {
  CRYPTO_once(&once, do_library_init);
  return 1;
}

static void do_library_init(void) {
  CRYPTO_init_sysrand();
  ERR_init();
}

Both libraries provide initialization functions, but wolfSSL's implementation includes reference counting and more explicit error handling, while BoringSSL's approach is more concise and relies on a separate initialization function.

Pros of Mbed-TLS

• More portable and lightweight, suitable for embedded systems and IoT devices
• Easier to integrate into existing projects due to its modular design
• Extensive documentation and examples for various use cases

Cons of Mbed-TLS

• Generally slower performance compared to BoringSSL
• Less frequent updates and potentially slower security patch releases
• Smaller community and fewer contributors compared to BoringSSL

Code Comparison

Mbed-TLS (initializing an SSL context):

mbedtls_ssl_context ssl;
mbedtls_ssl_config conf;

mbedtls_ssl_init(&ssl);
mbedtls_ssl_config_init(&conf);
mbedtls_ssl_config_defaults(&conf, MBEDTLS_SSL_IS_CLIENT, MBEDTLS_SSL_TRANSPORT_STREAM, MBEDTLS_SSL_PRESET_DEFAULT);

BoringSSL (initializing an SSL context):

SSL_CTX *ctx = SSL_CTX_new(TLS_method());
SSL *ssl = SSL_new(ctx);
BIO *bio = BIO_new_socket(sockfd, BIO_NOCLOSE);
SSL_set_bio(ssl, bio, bio);

Both libraries provide similar functionality for SSL/TLS operations, but BoringSSL's API is more closely aligned with OpenSSL, while Mbed-TLS has its own unique API design. BoringSSL is generally preferred for high-performance applications, while Mbed-TLS is better suited for resource-constrained environments.

Pros of s2n-tls

• Smaller codebase, making it easier to audit and maintain
• Designed with a focus on simplicity and security
• Optimized for performance in cloud environments

Cons of s2n-tls

• Limited feature set compared to BoringSSL
• Less widespread adoption and community support
• Primarily tailored for AWS services, potentially limiting its versatility

Code Comparison

s2n-tls:

int s2n_init(void)
{
    if (s2n_is_initialized) {
        return 0;
    }
    s2n_is_initialized = 1;
    return 0;
}

BoringSSL:

int CRYPTO_library_init(void) {
  CRYPTO_once(&once, do_library_init);
  return 1;
}

Both libraries provide initialization functions, but s2n-tls uses a simpler approach with a boolean flag, while BoringSSL employs a more complex initialization mechanism using CRYPTO_once.

s2n-tls focuses on a streamlined implementation, prioritizing simplicity and security. BoringSSL, being a fork of OpenSSL, offers a broader feature set and wider compatibility but at the cost of increased complexity.

The choice between these libraries depends on specific project requirements, with s2n-tls being particularly suitable for AWS-centric applications and BoringSSL offering more versatility for general-purpose use.

Pros of elliptic

• Lightweight and focused specifically on elliptic curve cryptography
• Pure JavaScript implementation, making it easily portable across platforms
• Extensive support for various elliptic curves and algorithms

Cons of elliptic

• Limited scope compared to BoringSSL's comprehensive cryptographic suite
• May have lower performance for certain operations due to JavaScript implementation
• Less extensive security auditing and backing compared to Google's resources

Code Comparison

BoringSSL (C):

EC_KEY *key = EC_KEY_new_by_curve_name(NID_X9_62_prime256v1);
EC_KEY_generate_key(key);
ECDSA_sign(0, digest, 32, signature, &siglen, key);

elliptic (JavaScript):

const ec = new EC('p256');
const key = ec.genKeyPair();
const signature = key.sign(digest);

Both libraries provide similar functionality for elliptic curve operations, but BoringSSL offers a more comprehensive cryptographic toolkit while elliptic focuses specifically on elliptic curve cryptography in a JavaScript environment.