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This commit is contained in:
Khaos Tian 2017-04-09 12:36:06 -07:00
parent 0c812b0145
commit 077567779d
1 changed files with 23 additions and 41 deletions
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64
lib/srp.js
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@ -41,33 +41,11 @@ function padToN(number, params) {
return padTo(new Buffer(n, 'hex'), params.N_length_bits / 8);
}
function padToH(number, params) {
assertIsBigInteger(number);
var hashlen_bits;
if (params.hash === "sha1")
hashlen_bits = 160;
else if (params.hash === "sha256")
hashlen_bits = 256;
else if (params.hash === "sha512")
hashlen_bits = 512;
else
throw Error("cannot determine length of hash '" +params.hash + "'");
return padTo(new Buffer(number, 'hex'), hashlen_bits / 8);
}
function assertIsBuffer(arg, argname) {
argname = argname || "arg";
assert_(Buffer.isBuffer(arg), "Type error: "+argname+" must be a buffer");
}
function assertIsNBuffer(arg, params, argname) {
argname = argname || "arg";
assert_(Buffer.isBuffer(arg), "Type error: "+argname+" must be a buffer");
if (arg.length != params.N_length_bits/8)
assert_(false, argname+" was "+arg.length+", expected "+(params.N_length_bits/8));
}
function assertIsBigInteger(arg) {
assert_(arg.constructor.name === 'BigInteger', "Type error: " + arg.argname + " must be a BigInteger");
}
@ -122,7 +100,7 @@ function computeVerifier(params, salt, I, P) {
assertIsBuffer(I, "identity (I)");
assertIsBuffer(P, "password (P)");
var v_num = params.g.modPow(getx(params, salt, I, P), params.N);
return padToN(v_num, params);
return v_num.toBuffer(true);
};
/*
@ -187,7 +165,7 @@ function getB(params, k, v, b) {
assertIsBigInteger(b);
var N = params.N;
var r = k.multiply(v).add(params.g.modPow(b, N)).mod(N);
return padToN(r, params);
return r.toBuffer(true);
};
/*
@ -208,7 +186,7 @@ function getA(params, a_num) {
if (Math.ceil(a_num.toString(16).length / 2) < 32) {
console.warn("getA: client key length", a_num.bitLength(), "is less than the recommended 256 bits");
}
return padToN(params.g.modPow(a_num, params.N), params);
return params.g.modPow(a_num, params.N).toBuffer(true);
};
/*
@ -226,10 +204,11 @@ function getA(params, a_num) {
* returns: u (bignum) shared scrambling parameter
*/
function getu(params, A, B) {
assertIsNBuffer(A, params, "A");
assertIsNBuffer(B, params, "B");
assertIsBuffer(A, params, "A");
assertIsBuffer(B, params, "B");
var u_buf = crypto.createHash(params.hash)
.update(A).update(B)
.update(padTo(A, params.N_length_bits / 8))
.update(padTo(B, params.N_length_bits / 8))
.digest();
return(new BigInteger(u_buf));
};
@ -257,8 +236,7 @@ function client_getS(params, k_num, x_num, a_num, B_num, u_num) {
if((zero.compareTo(B_num) > 0) && (N.compareTo(B_num) < 0))
throw new Error("invalid server-supplied 'B', must be 1..N-1");
var S_num = B_num.subtract(k_num.multiply(params.g.modPow(x_num, params.N))).modPow(a_num.add(u_num.multiply(x_num)), params.N).mod(params.N);
return padToN(S_num, params);
return S_num.toBuffer(true);
};
/*
@ -278,11 +256,10 @@ function server_getS(params, v_num, A_num, b_num, u_num) {
assertIsBigInteger(A_num);
assertIsBigInteger(b_num);
assertIsBigInteger(u_num);
//! if (zero.greater(A_num) || N.lesser(A_num))
if((zero.compareTo(A_num) > 0) && (N.compareTo(A_num) < 0))
throw new Error("invalid client-supplied 'A', must be 1..N-1");
var S_num = A_num.multiply(v_num.modPow(u_num, params.N)).modPow(b_num, params.N).mod(params.N);
return padToN(S_num, params);
return S_num.toBuffer(true);
};
/*
@ -295,17 +272,24 @@ function server_getS(params, v_num, A_num, b_num, u_num) {
* returns: buffer
*/
function getK(params, S_buf) {
assertIsNBuffer(S_buf, params, "S");
return crypto.createHash(params.hash)
.update(S_buf)
.digest();
assertIsBuffer(S_buf, params, "S");
if (params.hash === "sha1") {
// use t_mgf1 interleave for short sha1 hashes
return Buffer.concat([
crypto.createHash(params.hash).update(S_buf).update(Buffer.from([0,0,0,0])).digest(),
crypto.createHash(params.hash).update(S_buf).update(Buffer.from([0,0,0,1])).digest()
]);
} else {
// use hash as-is otherwise
return crypto.createHash(params.hash).update(S_buf).digest();
}
};
function getM1(params, u_buf, s_buf, A_buf, B_buf, K_buf) {
assertIsBuffer(u_buf, params, "identity (I)");
assertIsBuffer(s_buf, params, "salt (s)")
assertIsNBuffer(A_buf, params, "A");
assertIsNBuffer(B_buf, params, "B");
assertIsBuffer(A_buf, params, "A");
assertIsBuffer(B_buf, params, "B");
assertIsBuffer(K_buf, params, "K");
var hN = crypto.createHash(params.hash).update(params.N.toBuffer(true)).digest();
@ -323,7 +307,7 @@ function getM1(params, u_buf, s_buf, A_buf, B_buf, K_buf) {
}
function getM2(params, A_buf, M1_buf, K_buf) {
assertIsNBuffer(A_buf, params, "A");
assertIsBuffer(A_buf, params, "A");
assertIsBuffer(M1_buf, params, "M1");
assertIsBuffer(K_buf, params, "K");
@ -365,8 +349,6 @@ Client.prototype = {
var u_num = getu(p.params, p.A_buf, B_buf);
var S_buf_x = client_getS(p.params, p.k_num, p.x_num, p.a_num, B_num, u_num);
p.K_buf = getK(p.params, S_buf_x);
p.M1_buf = getM1(p.params, p.A_buf, B_buf, S_buf_x);
p.M2_buf = getM2(p.params, p.A_buf, p.M1_buf, p.K_buf);
p.u_num = u_num; // only for tests
p.S_buf = S_buf_x; // only for tests
p.B_buf = B_buf;