C# - 윈도우 시스템에서 지원하는 암호화 목록(Cipher Suites) 나열

아래의 문서에,

Prioritizing Schannel Cipher Suites
; https://learn.microsoft.com/en-us/windows/win32/secauthn/prioritizing-schannel-cipher-suites

기존의 CryptoAPI를 대체하기 위해 Windows Server 2008/Vista부터 지원하기 시작한 CNG(Cryptography API Next Generation) API를 이용한 암호화 목록(Cipher Suites)을 구하는 방법이 나옵니다.

C#으로 포팅하면 이렇게 다룰 수 있는데요,

using System.Runtime.InteropServices;

namespace ConsoleApp1;

public unsafe struct CRYPT_CONTEXT_FUNCTIONS
{
    public uint cFunctions;
    public IntPtr rgpszFunctions;
}

internal class Program
{
    [DllImport("Bcrypt.dll", CharSet = CharSet.Unicode)]
    public unsafe static extern int BCryptEnumContextFunctions(uint dwTable, string pszContext,
        uint dwInterface, ref uint pcbBuffer, CRYPT_CONTEXT_FUNCTIONS** ppBuffer);

    [DllImport("Bcrypt.dll")]
    public static extern void BCryptFreeBuffer(IntPtr pvBuffer);

    public const uint CRYPT_LOCAL = 0x00000001;
    public const int ERROR_SUCCESS = 0;
    public const uint NCRYPT_SCHANNEL_INTERFACE = 0x00010002;

    static unsafe void Main(string[] args)
    {
        uint cbBuffer = 0;
        CRYPT_CONTEXT_FUNCTIONS* pBuffer = null;

        int status = BCryptEnumContextFunctions(CRYPT_LOCAL, "ssl", NCRYPT_SCHANNEL_INTERFACE, ref cbBuffer, &pBuffer);
        if (status != 0)
        {
            Console.WriteLine($"**** Error 0x{status:x} returned by BCryptEnumContextFunctions");
            return;
        }

        if (pBuffer == null)
        {
            Console.WriteLine("**** Error pBuffer returned from BCryptEnumContextFunctions is null");
            return;
        }

        IntPtr basePtr = pBuffer->rgpszFunctions;

        for (int i = 0; i < pBuffer->cFunctions; i ++)
        {
            IntPtr offset = basePtr + (i * IntPtr.Size);
            IntPtr target = Marshal.ReadIntPtr(offset);

            string? functionName = Marshal.PtrToStringUni(target);
            if (functionName == null )
            {
                continue;
            }

            Console.WriteLine($"Function {i}: {functionName}");
        }

        if (pBuffer != null)
        {
            BCryptFreeBuffer((IntPtr)pBuffer);
        }
    }
}

Windows 11(10.0.22621.1702)에서 테스트하면 다음과 같은 결과를 얻을 수 있습니다.

// 이름 포맷 형식: https://www.sysnet.pe.kr/2/0/11155#naming
// PowerShell이라면 "Get-TlsCipherSuite).Name" 명령어로 쉽게 구할 수 있고,
// (CSS_SQL_Networking_Tools로 배포하는) SQLCheck 도구를 다운로드해 실행하면 로그 파일의 출력에서도 구할 수 있습니다.
//
// Windows 10의 경우 "TLS Cipher Suites in Windows 10 v1607" 참고

Function 0: TLS_AES_256_GCM_SHA384
Function 1: TLS_AES_128_GCM_SHA256
Function 2: TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384
Function 3: TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256
Function 4: TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384
Function 5: TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
Function 6: TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384
Function 7: TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256
Function 8: TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384
Function 9: TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256
Function 10: TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA
Function 11: TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA
Function 12: TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA
Function 13: TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA
Function 14: TLS_RSA_WITH_AES_256_GCM_SHA384
Function 15: TLS_RSA_WITH_AES_128_GCM_SHA256
Function 16: TLS_RSA_WITH_AES_256_CBC_SHA256
Function 17: TLS_RSA_WITH_AES_128_CBC_SHA256
Function 18: TLS_RSA_WITH_AES_256_CBC_SHA
Function 19: TLS_RSA_WITH_AES_128_CBC_SHA
Function 20: TLS_RSA_WITH_NULL_SHA256
Function 21: TLS_RSA_WITH_NULL_SHA
Function 22: TLS_PSK_WITH_AES_256_GCM_SHA384
Function 23: TLS_PSK_WITH_AES_128_GCM_SHA256
Function 24: TLS_PSK_WITH_AES_256_CBC_SHA384
Function 25: TLS_PSK_WITH_AES_128_CBC_SHA256
Function 26: TLS_PSK_WITH_NULL_SHA384
Function 27: TLS_PSK_WITH_NULL_SHA256

아래는 Windows Server 2008 R2(6.1.7601) ~ Windows Server 2012 R2(6.3.9600)의 결과이고,

Function 0: TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384_P256
Function 1: TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384_P384
Function 2: TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256
Function 3: TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P384
Function 4: TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA_P256
Function 5: TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA_P384
Function 6: TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA_P256
Function 7: TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA_P384
Function 8: TLS_DHE_RSA_WITH_AES_256_GCM_SHA384
Function 9: TLS_DHE_RSA_WITH_AES_128_GCM_SHA256
Function 10: TLS_DHE_RSA_WITH_AES_256_CBC_SHA
Function 11: TLS_DHE_RSA_WITH_AES_128_CBC_SHA
Function 12: TLS_RSA_WITH_AES_256_GCM_SHA384
Function 13: TLS_RSA_WITH_AES_128_GCM_SHA256
Function 14: TLS_RSA_WITH_AES_256_CBC_SHA256
Function 15: TLS_RSA_WITH_AES_128_CBC_SHA256
Function 16: TLS_RSA_WITH_AES_256_CBC_SHA
Function 17: TLS_RSA_WITH_AES_128_CBC_SHA
Function 18: TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384_P384
Function 19: TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256_P256
Function 20: TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256_P384
Function 21: TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384_P384
Function 22: TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256_P256
Function 23: TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256_P384
Function 24: TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA_P256
Function 25: TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA_P384
Function 26: TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA_P256
Function 27: TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA_P384
Function 28: TLS_DHE_DSS_WITH_AES_256_CBC_SHA256
Function 29: TLS_DHE_DSS_WITH_AES_128_CBC_SHA256
Function 30: TLS_DHE_DSS_WITH_AES_256_CBC_SHA
Function 31: TLS_DHE_DSS_WITH_AES_128_CBC_SHA
Function 32: TLS_RSA_WITH_3DES_EDE_CBC_SHA
Function 33: TLS_DHE_DSS_WITH_3DES_EDE_CBC_SHA
Function 34: TLS_RSA_WITH_RC4_128_SHA
Function 35: TLS_RSA_WITH_RC4_128_MD5
Function 36: TLS_RSA_WITH_NULL_SHA256
Function 37: TLS_RSA_WITH_NULL_SHA
Function 38: SSL_CK_RC4_128_WITH_MD5
Function 39: SSL_CK_DES_192_EDE3_CBC_WITH_MD5

아래는 Windows Server 2022 (10.0.20348.1726)에서의 결과입니다.

Function 0: TLS_AES_256_GCM_SHA384
Function 1: TLS_AES_128_GCM_SHA256
Function 2: TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384
Function 3: TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256
Function 4: TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384
Function 5: TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
Function 6: TLS_DHE_RSA_WITH_AES_256_GCM_SHA384
Function 7: TLS_DHE_RSA_WITH_AES_128_GCM_SHA256
Function 8: TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384
Function 9: TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256
Function 10: TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384
Function 11: TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256
Function 12: TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA
Function 13: TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA
Function 14: TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA
Function 15: TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA
Function 16: TLS_RSA_WITH_AES_256_GCM_SHA384
Function 17: TLS_RSA_WITH_AES_128_GCM_SHA256
Function 18: TLS_RSA_WITH_AES_256_CBC_SHA256
Function 19: TLS_RSA_WITH_AES_128_CBC_SHA256
Function 20: TLS_RSA_WITH_AES_256_CBC_SHA
Function 21: TLS_RSA_WITH_AES_128_CBC_SHA
Function 22: TLS_RSA_WITH_3DES_EDE_CBC_SHA
Function 23: TLS_RSA_WITH_NULL_SHA256
Function 24: TLS_RSA_WITH_NULL_SHA
Function 25: TLS_PSK_WITH_AES_256_GCM_SHA384
Function 26: TLS_PSK_WITH_AES_128_GCM_SHA256
Function 27: TLS_PSK_WITH_AES_256_CBC_SHA384
Function 28: TLS_PSK_WITH_AES_128_CBC_SHA256
Function 29: TLS_PSK_WITH_NULL_SHA384
Function 30: TLS_PSK_WITH_NULL_SHA256

(첨부 파일은 이 글의 예제 코드를 포함합니다.)

---

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[최초 등록일: 6/10/2023]
[최종 수정일: 6/15/2023]


이 저작물은 크리에이티브 커먼즈 코리아 저작자표시-비영리-변경금지 2.0 대한민국 라이센스에 따라 이용하실 수 있습니다.

by SeongTae Jeong, mailto:techsharer at outlook.com