diffie-hellman

According to that piece of documentation: https://wiki.openssl.org/index.php/Diffie_Hellman#Using_the_Low_Level_APIs Using the Low level API's for Diffie Hellman (need to perform a group Key agreement). For simplicity I need to provide fixed values for Diffie Hellman p and g values for now I use the function DH_generate_parameters_ex but any solution using these options may add a communication overhead and there are fixed values for p and g for Diffie Hellman offering good security. So using the approach convention over configuration, how I can set fixed values especially the ones specified in

RFC5683阅读笔记 Password-Authenticated Key(PAK) Diffie-Hellman Exchange 摘要 Diffie-Hellman（简称DH）密钥交换是最早的密钥交换算法之一，使得通信双方能在非安全的信道中安全的交换密钥，用于加密后续的通信消息。 在本文档中提出了一种算法用于在未经身份鉴别的Diffie-Hellman算法中添加双向的身份鉴别，这种算法称为Password-Authenticated Key(PAK)交换，它允许双方在执行Diffie-Hellman密钥交换时进行身份鉴别。 文档认为这种协议足够安全可以抵挡所有的主动攻击和被动攻击，而且不允许任何的攻击者获得可以用于进行字典攻击的信息。 文档规定 A 代表实体Alice B 代表实体Bob Ra是指由A选择的随机秘密指数 Rb是指由B选择的随机秘密指数 Xab表示由B得出的值（X可能由A计算） Yba表示由A得出的值（Y可能由B计算） 当a除以b时，a mod b表示最小的非负余数 Hi(u)表示在字符串u上计算的商定函数（例如基于SHA-1，SHA-256等），各种H()充当独立的随机函数，H1(u)和H2(u)是关键推导函数，H3(u)、H4(u)和H5(u)是哈希函数。 s | t表示字符串S和T的串联 ^表示幂 乘、除和求幂运算都是针对一个p元域执行的，也就是说 a b

I have 'secured' the communication between my android application and a tls server providing a financial transaction service, currently in development. The security credentials are stored in a BKS keystore included in the Android apk. The password to the keystore is visible in plain text in the application source: keyStore.load(is, "passwd".toCharArray()); I am concerned that if someone was to reverse engineer the app, they would be able to impersonate another user and compromise the security of the service. I was wondering whether there is a fault in my implementation, if anyone else has this

I am trying to do ECDHE key exchange over TLS 1.2 using .net. The server is responding with a server_key_exchange message, which begins with 04, so I guess it is unencrypted. From my understanding the first 32 bits of the message are considered as a value X, and the next 32 bits are considered as a value Y. Using these, and the elliptic curve (say secp256r1), the value of public key of server is created. I am referring to the following python code from OpenTLS : class ECDHE_RSA_Key_Exchange: def __init__(self, server_key_exchange): curve_code = bytes_to_hex(server_key_exchange[5:7]) print(

I need to generate an EC Diffie Hellman key pair. I am using the secp256r1 named curve, and OpenSSL. This is what I have with me so far: unsigned char *ecdh(size_t *secret_len) { EVP_PKEY_CTX *pctx, *kctx; EVP_PKEY_CTX *ctx; unsigned char *secret; EVP_PKEY *pkey = NULL, *peerkey, *params = NULL; /* NB: assumes pkey, peerkey have been already set up */ /* Create the context for parameter generation */ if(NULL == (pctx = EVP_PKEY_CTX_new_id(EVP_PKEY_EC, NULL))) printf("Error in EC key generation\n"); /* Initialise the parameter generation */ if(1 != EVP_PKEY_paramgen_init(pctx)) printf("Error in

I'm writing an app that'll exchange data between a phone and a Windows PC, and I want to protect the data sent with key generated with a Diffie-Hellman exchange. I'm trying to use BouncyCastle for that, but the almost non-existant documentation for the C# implementation has me stumped. What I want to know is: what's the workflow for generating a DH key and computing a shared key when the other side's key is received? (I'm assuming I can send my key as a string and I can work with the other side's key as a string.) What objects/methods do I use in C# for that? Alright, after a lot of trial, I

I am writing a test harness in java for an existing program. As part of this i need to generate a Diffie Hellman key pair and pass the public key to the other program in its raw (i.e unencoded bytes) form. I can successfully the key pair using the following code: KeyPairGenerator kpg = KeyPairGenerator.getInstance("DiffieHellman"); kpg.initialize(512); KeyPair dkp = kpg.generateKeyPair(); However, i cannot seem to retrieve the raw byte value of the keys :-( Calling dkp.getPublic().getEncoded() returns a byte array but its of the Key in an x509 encoded format. Three possible ways forward occur