1 /*

     2  * The Diffie-Hellman key exchange protocol.

     3  */

     4 

     5 // Our prime number as a base for operations.

     6 var dh_prime = '82818079787776757473727170696867666564636261605958575655545352515049484746454443424140393837363534333231302928272625242322212019181716151413121110987654321';

     7 

     8 // g, a primitive root used as an exponent

     9 // (2 and 5 are acceptable, but BigInt is faster with odd numbers)

    10 var dh_g = '5';

    11 

    12 /**

    13  * Generates a Diffie-Hellman private key

    14  * @return string(BigInt)

    15  */

    16 

    17 function dh_gen_private()

    18 {

    19   return EnanoMath.RandomInt(256);

    20 }

    21 

    22 /**

    23  * Calculates the public key from the private key

    24  * @param string(BigInt)

    25  * @return string(BigInt)

    26  */

    27 

    28 function dh_gen_public(b)

    29 {

    30   return EnanoMath.PowMod(dh_g, b, dh_prime);

    31 }

    32 

    33 /**

    34  * Calculates the shared secret.

    35  * @param string(BigInt) Our private key

    36  * @param string(BigInt) Remote party's public key

    37  * @return string(BigInt)

    38  */

    39 

    40 function dh_gen_shared_secret(b, A)

    41 {

    42   return EnanoMath.PowMod(A, b, dh_prime);

    43 }

    44