1 Topic by leroyk2

(1 replies, posted in wolfCrypt)

When the authentication tag made with wc_AesGcmEncrypt is different when trying to decrypt with wc_AesGcmDecryp I expect some kind of error result.


In aes.c function wc_AesGcmDecrypt with WOLFSSL_STM32_CUBEMX define:

 if (ret == 0 && ConstantCompare(authTag, tag, authTagSz) == 0) {
        /* Only keep the decrypted data if authTag success. */
        XMEMCPY(out, inPadded, sz);
        ret = 0; /* success */
    }

If the result of ConstantCompare is not zero ret will still be zero. I expect that ret will be negative because the given auth tag does not match with the calculated one in the decrypt function. The data is successfully decrypted but the additional data could be compromised.

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2 Reply by leroyk2

(3 replies, posted in wolfCrypt)

I need to know if I could exchange a diffie hellman public key from wolfssl to openssl

wc_DhGenerateKeyPair(&key, &rng, priv, &privSz, pub, &pubSz);
is the output of pub compatible with openssl bignum?

device x = will be used openssl DH_compute_key
device y = will be used wolfssl wc_DhAgree

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3 Topic by leroyk2

(3 replies, posted in wolfCrypt)

Hello, I want to use wolfSSL on my STM32 F4 device and openssl on my Windows application.
Is it possible to perform a Diffie-Hellman key exchange between both?

wc_DhGenerateKeyPair/wc_DhAgree uses a byte array, can I export or import to a format supported by both openSSL and wolfSSL? Thanks for your advice.

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