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A few small code cleanups for cryptography

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* Remove some unused cryptographic code
* Add some notes about how Minecraft's cryptography choices have not quite survived the test of time
This commit is contained in:
Andrew Steinborn
2024-12-21 03:45:17 -05:00
parent 39191957ea
commit af97ffffa5
5 changed files with 36 additions and 54 deletions
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9
native/src/main/c/jni_cipher_macos.c
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@@ -26,6 +26,15 @@ Java_com_velocitypowered_natives_encryption_OpenSslCipherImpl_init(JNIEnv *env,
return 0;
}
// But, you're saying, *why* are we using the key as the IV? After all, reusing the key as
// the IV defeats the entire point - we might as well just initialize it to all zeroes.
//
// You can blame Mojang. For the record, we also don't consider the Minecraft protocol
// encryption scheme to be secure, and it has reached the point where any serious cryptographic
// protocol needs a refresh. There are multiple obvious weaknesses, and this is far from the
// most serious.
//
// If you are using Minecraft in a security-sensitive application, *I don't know what to say.*
CCCryptorRef cryptor = NULL;
CCCryptorStatus result = CCCryptorCreateWithMode(encrypt ? kCCEncrypt : kCCDecrypt,
kCCModeCFB8,

9
native/src/main/c/jni_cipher_openssl.c
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@@ -32,6 +32,15 @@ Java_com_velocitypowered_natives_encryption_OpenSslCipherImpl_init(JNIEnv *env,
return 0;
}
// But, you're saying, *why* are we using the key as the IV? After all, reusing the key as
// the IV defeats the entire point - we might as well just initialize it to all zeroes.
//
// You can blame Mojang. For the record, we also don't consider the Minecraft protocol
// encryption scheme to be secure, and it has reached the point where any serious cryptographic
// protocol needs a refresh. There are multiple obvious weaknesses, and this is far from the
// most serious.
//
// If you are using Minecraft in a security-sensitive application, *I don't know what to say.*
int result = EVP_CipherInit(ctx, EVP_aes_128_cfb8(), (byte*) keyBytes, (byte*) keyBytes,
encrypt);
if (result != 1) {

9
native/src/main/java/com/velocitypowered/natives/encryption/JavaVelocityCipher.java
View File

@@ -48,6 +48,15 @@ public class JavaVelocityCipher implements VelocityCipher {
private JavaVelocityCipher(boolean encrypt, SecretKey key) throws GeneralSecurityException {
this.cipher = Cipher.getInstance("AES/CFB8/NoPadding");
// But, you're saying, *why* are we using the key as the IV? After all, reusing the key as
// the IV defeats the entire point - we might as well just initialize it to all zeroes.
//
// You can blame Mojang. For the record, we also don't consider the Minecraft protocol
// encryption scheme to be secure, and it has reached the point where any serious cryptographic
// protocol needs a refresh. There are multiple obvious weaknesses, and this is far from the
// most serious.
//
// If you are using Minecraft in a security-sensitive application, *I don't know what to say.*
this.cipher.init(encrypt ? Cipher.ENCRYPT_MODE : Cipher.DECRYPT_MODE, key,
new IvParameterSpec(key.getEncoded()));
}