Pros of openssh-portable

• Comprehensive and battle-tested SSH implementation
• Supports a wide range of SSH features and protocols
• Extensively audited for security vulnerabilities

Cons of openssh-portable

• Large codebase with complex architecture
• Steeper learning curve for integration into custom applications
• Requires more system resources due to its full-featured nature

Code Comparison

openssh-portable (server setup):

int
main(int ac, char **av)
{
    /* Initialize the SSH server */
    ssh_init();
    /* Configure and start the server */
    ssh_bind = ssh_bind_new();
    ssh_bind_options_set(ssh_bind, SSH_BIND_OPTIONS_BINDADDR, "0.0.0.0");
    ssh_bind_listen(ssh_bind);
}

ssh (server setup):

func main() {
    ssh.Handle(func(s ssh.Session) {
        io.WriteString(s, "Welcome to my SSH server\n")
    })
    log.Fatal(ssh.ListenAndServe(":2222", nil))
}

The openssh-portable example shows a more low-level C implementation with explicit initialization and configuration steps. The ssh example demonstrates a higher-level Go implementation with a simpler API, focusing on handling SSH sessions directly.

Pros of Paramiko

• More comprehensive SSH implementation with support for various authentication methods and SSH operations
• Extensive documentation and a large, active community
• Cross-platform compatibility (Windows, macOS, Linux)

Cons of Paramiko

• Heavier and more complex library, which may be overkill for simple SSH tasks
• Slower performance compared to gliderlabs/ssh for basic SSH server implementations

Code Comparison

Paramiko (client connection):

import paramiko

client = paramiko.SSHClient()
client.set_missing_host_key_policy(paramiko.AutoAddPolicy())
client.connect('hostname', username='user', password='pass')
stdin, stdout, stderr = client.exec_command('ls -l')
print(stdout.read().decode())

gliderlabs/ssh (server implementation):

ssh.Handle(func(s ssh.Session) {
    io.WriteString(s, fmt.Sprintf("Hello %s\n", s.User()))
})

log.Fatal(ssh.ListenAndServe(":2222", nil))

gliderlabs/ssh focuses on simplicity and ease of use for SSH server implementations, while Paramiko offers a more comprehensive SSH toolkit for both client and server operations. The choice between the two depends on the specific requirements of your project and the level of SSH functionality needed.

Pros of crypto

• More comprehensive cryptographic functionality
• Part of the official Go project, ensuring long-term maintenance
• Extensive documentation and community support

Cons of crypto

• Higher complexity for simple SSH implementations
• Requires more setup and configuration for basic SSH tasks
• Less focused on SSH-specific features

Code Comparison

crypto:

config := &ssh.ServerConfig{
    PasswordCallback: func(c ssh.ConnMetadata, pass []byte) (*ssh.Permissions, error) {
        if c.User() == "user" && string(pass) == "password" {
            return nil, nil
        }
        return nil, fmt.Errorf("password rejected for %q", c.User())
    },
}

ssh:

ssh.Handle(func(s ssh.Session) {
    io.WriteString(s, fmt.Sprintf("Hello %s\n", s.User()))
})

ssh.ListenAndServe(":2222", nil)

Summary

crypto provides a more comprehensive cryptographic toolkit, while ssh focuses on simplifying SSH server implementation. crypto offers broader functionality but requires more setup for basic SSH tasks. ssh provides a more straightforward API for creating SSH servers but may lack some advanced features found in crypto. The choice between the two depends on the specific requirements of your project and the level of control you need over the SSH implementation.

Pros of Win32-OpenSSH

• Full Windows integration and native support
• Comprehensive SSH functionality, including SFTP and SCP
• Actively maintained by Microsoft, ensuring long-term support

Cons of Win32-OpenSSH

• Larger codebase and more complex implementation
• Primarily focused on Windows, limiting cross-platform compatibility
• Steeper learning curve for customization and integration

Code Comparison

Win32-OpenSSH (C):

int main(int argc, char **argv) {
    /* Initialize OpenSSH */
    ssh_init();
    /* Main SSH server loop */
    ssh_server_loop();
    return 0;
}

ssh (Go):

func main() {
    ssh.Handle(func(s ssh.Session) {
        io.WriteString(s, "Welcome to the SSH server!\n")
    })
    log.Fatal(ssh.ListenAndServe(":2222", nil))
}

Summary

Win32-OpenSSH provides a comprehensive SSH solution for Windows environments, offering full integration and native support. It includes a wide range of SSH functionalities and is actively maintained by Microsoft. However, it has a larger codebase and is primarily focused on Windows.

ssh, on the other hand, is a lightweight Go library for building SSH servers. It offers simplicity and ease of use, making it ideal for custom SSH server implementations. While it may not have all the features of Win32-OpenSSH, it provides greater flexibility and cross-platform compatibility.

The code comparison highlights the difference in complexity and approach between the two projects, with Win32-OpenSSH using a more traditional C implementation and ssh utilizing Go's simplicity and concurrency features.

Pros of libssh2

• More comprehensive and feature-rich SSH implementation
• Supports a wider range of SSH protocols and algorithms
• Better suited for complex SSH operations and integrations

Cons of libssh2

• Steeper learning curve due to its extensive API
• Requires more setup and configuration for basic use cases
• Less Go-friendly, as it's primarily a C library

Code Comparison

libssh2:

#include <libssh2.h>

LIBSSH2_SESSION *session;
session = libssh2_session_init();
if (libssh2_session_handshake(session, sock) != 0) {
    fprintf(stderr, "Failure establishing SSH session\n");
}

ssh:

import "github.com/gliderlabs/ssh"

ssh.ListenAndServe(":2222", func(s ssh.Session) {
    io.WriteString(s, "Welcome to my SSH server\n")
})

The libssh2 example shows the initialization of an SSH session in C, while the ssh example demonstrates a simple SSH server setup in Go. ssh provides a more straightforward API for basic SSH server functionality, making it easier to use for simpler use cases, especially in Go projects. However, libssh2 offers more flexibility and features for complex SSH implementations across various programming languages.