我正在尝试使用 BouncyCastle 在运行 mbedTLS 的嵌入式设备和 Java 之间进行 ECDH。当我比较生成的密钥长度时,我得到一个 mbedTLS 制作的 66 字节密钥和 BC 制作的 65 字节密钥。附上伪代码:
KeyPairGenerator kpg = KeyPairGenerator.getInstance("EC", "BC");
kpg.initialize(256);
KeyPair localKp = kpg.generateKey();
ASN1Sequence sequence = DERSequence.getInstance(localKp.getPublic().getEncoded());
DERBitString subjectPublicKey = (DERBitString) sequence.getObjectAt(1);
byte[] encodedLocalPublicKey = subjectPublicKey.getBytes();
// encodedLocalPublicKey.length -> 65
MbedTLS:
mbedtls_ecdh_context ecdh;
mbedtls_ctr_drbg_context ctr_drbg;
mbedtls_entropy_context entropy;
const char pers[] = "ecdh";
mbedtls_ctr_drbg_init(&ctr_drbg);
mbedtls_entropy_init(&entropy);
mbedtls_ecdh_init(&ecdh);
int ret = 0;
if((ret = mbedtls_ctr_drbg_seed( &ctr_drbg, mbedtls_entropy_func, &entropy,
(const unsigned char *) pers,
sizeof pers )) != 0) {
mbedtls_printf( " failed\n ! mbedtls_ctr_drbg_seed returned %d\n", ret );
}
ret = mbedtls_ecp_group_load(&ecdh.grp, MBEDTLS_ECP_DP_SECP256R1);
if (ret != 0) {
mbedtls_printf( " failed\n ! mbedtls_ecp_group_load returned %d\n", ret );
}
size_t olen;
unsigned char buf[1024];
ret = mbedtls_ecdh_make_public(&ecdh, &olen, buf, sizeof(buf), mbedtls_ctr_drbg_random, &ctr_drbg);
// ret is 0, olen is 66
当我将 MbedTLS 密钥加载到 Java 中时,它会抛出 java.lang.IllegalArgumentException: Invalid point encoding 0x41 :
byte[] publicKeyBytes = ... FROM MbedTLS
log.info("Public key length: {}", publicKeyBytes.length); // Shows 66
ECParameterSpec ecSpec = ECNamedCurveTable.getParameterSpec("P-256");
ECPoint point = ecSpec.getCurve().decodePoint(publicKeyBytes); // This line throws
我尝试在 Java 和 MbedTLS 之间做 ECDH Java。两个测试都成功了,但他们无法跨平台交换。
我究竟做错了什么?对不起,也许是明显的问题,但我正在努力解决它。我将不胜感激。
谢谢你。