Codetronik

Kyber는 키 캡슐화 메커니즘으로, 쉽게 설명하면 공유 키(AES)를 유도할때 사용한다고 보면 된다.

Kyber의 보안 강도는 아래와 같다.

Kyber-512 = AES-128

Kyber-768 = AES-192

Kyber-1024 = AES-256

테스트 코드 : https://github.com/pq-crystals/kyber 빌드 후, test_vectors를 실행

*공식에서는 Kyber768 사용을 권장하지만, 귀찮아서 그냥 Kyber512로 진행하였음

1. Bob이 공개 키와 비밀 키를 생성

Public Key: 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
Secret Key: 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

2. Alice는 Bob의 공개 키를 사용하여 공유 키를 유도하고, 이를 캡슐화 함

Ciphertext: 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
Shared Key: 221d7d86011659313c83ce3fd0ab26797ef217e11d1f0bc76e7952fbe52a0a58

3. Bob은 Alice가 보낸 캡슐화된 키를 자신의 비밀 키로 복호화하여 Alice와 동일한 공유키를 얻음

Shared Key: 221d7d86011659313c83ce3fd0ab26797ef217e11d1f0bc76e7952fbe52a0a58

Kyber 공식 홈페이지에서는 하이브리드를 권장한다. 예) Kyber+ECDH
키 교환에 대해서는 아래를 참조
https://www.ietf.org/archive/id/draft-ietf-tls-hybrid-design-12.html

만약 크롬을 사용중이라면, 아래에 접속하여 TLS 1.3 kyber 사용을 활성화 할 수 있다.

1. 환경 설정 (wsl 기준)

$ git clone https://github.com/emscripten-core/emsdk.git
$ cd emsdk
$ ./emsdk install latest
$ ./emsdk activate latest
$ source ./emsdk_env.sh
$ emcc --version

2. hello.c 작성

#include <stdio.h>

int main() {
    printf("Hello World\n");
    return 0;
}

3. 컴파일

emcc hello.c -o hello.html

4. 서버 구동

npx http-server ~ -o -p 9999

참고

https://emscripten.org/docs/getting_started/downloads.html#sdk-download-and-install

https://emscripten.org/docs/tools_reference/emcc.html#emccdoc

https://developer.mozilla.org/ko/docs/WebAssembly/C_to_Wasm

알아낸 것 1. 샌드 박스 내부는 리눅스 스타일로 구성되어 있음. 아래는 직접 돌려본 예시

/tmp
/home
/home/web_user
/dev
/dev/null
/dev/tty
/dev/tty1
/dev/random
/dev/urandom
/dev/shm
/dev/shm/tmp
/dev/stdin
/dev/stdout
/dev/stderr
/proc
/proc/self
/proc/self/fd
/proc/self/fd/0
/proc/self/fd/1
/proc/self/fd/2
/proc/self/fd/3
/proc/self/fd/4
/proc/self/fd/5
/proc/self/fd/6

알아낸 것  2. C코드로 디컴파일 가능

LLVM 기반이기 때문에 OLLVM 개발 가능

https://github.com/HakonHarnes/emcc-obf

알아낸 것  3. int main()의 주소는 0x1

이것은 전형적인 메모리 레이아웃은 아님

예제 참조 : https://github.com/codetronik/KeyStoreExample

아래 코드를 실행하면, certificateChain에 인증서 체인이 저장된다.

val kpg = KeyPairGenerator.getInstance(KeyProperties.KEY_ALGORITHM_EC, "AndroidKeyStore")

kpg.initialize(
		KeyGenParameterSpec.Builder(SIGN_KEY_ALIAS, KeyProperties.PURPOSE_SIGN or KeyProperties.PURPOSE_VERIFY)
			.setAttestationChallenge(challenge)
			.setIsStrongBoxBacked(isStrongBoxSupported())
			.build())

kpg.generateKeyPair()

val certificateChain = keyStore.getCertificateChain(SIGN_KEY_ALIAS)

인증서는 총 4개(리프, 중간-1, 중간-2, 루트 순)로 구성되어 있다. (구형 기기는 다름)

루트 인증서는 고정이며, 중간 인증서 2개는 발급자가 기기마다.. ?? (같은 모델에서 확인 필요)

루트 인증서의 공개키는 https://developer.android.com/privacy-and-security/security-key-attestation?hl=ko#root_certificate에서 제공하는 것과 일치한다. 이 키로 루트 인증서 및 중간-2 인증서를 검증한다.

만약, vendor로부터 직접 전달받은 출시 전 테스트폰이라면, 구글 루트 인증서가 아닌, 벤더 루트 인증서일 확률이 높다.

중간-2 인증서로 중간-1 인증서를 검증한다.

중간-1 인증서로 리프 인증서를 검증한다.

리프 인증서에는 확장 OID 1.3.6.1.4.1.11129.2.1.17 가 존재하며, 기기증명 콘텐츠가 포함되어 있다.

각 항목에 대한 설명은 아래 링크에 참고

https://source.android.com/docs/security/features/keystore/attestation?hl=ko

https://developer.android.com/privacy-and-security/security-key-attestation?hl=ko

아래는 나의 갤럭시 S20 노트에서 확인한 기기증명 콘텐츠이다.