BitGo lost password - node.js

Question

a friend of mine lost her password for a BitGo account. her "Key Card" contains her private key in the form (actual info redacted for security reasons):
User Key:
{"iv":"IDMkr...UH4g0TBCofAcIg","v":1,"iter":10000,"ks":256,"ts":64,"mode":"ccm","adata":"","cipher":"aes","salt":"lI8k...vhX0","ct":"Kf...LOmgbn67w2CRYBhcXtX
0wdPF3D7ThCKaeZhTymin9hcMD5eL...AosmmvfA8npiDIHWgvdbHAk"}
and it's clear that the "ct" (ciphertext) was encrypted using AES 256 CCM. I've found a module (https://github.com/spark/node-aes-ccm) that will help me decrypt the private key ("ct") but the docs for the module are not very helpful:
decrypt(key, iv, ciphertext, aad, auth_tag)
key, iv, plaintext, aad, and auth_tag are all Buffer objects. decrypt will return an object like the following:
{
plaintext: Buffer,
auth_ok: Boolean
}
so other than that the parameters are buffers, there's no description for them... however, it seems I've got everything I need except the key. from reading the docs on a related module (https://github.com/xorbit/node-aes-gcm):
key is a 16, 24 or 32-byte Buffer object containing the AES key used
for encryption
I gather this is the key with which the private key was encrypted, but where would I get that and how does it relate to the lost password?
any help greatly appreciated
* Addendum I *
my friend figured out the password so following Ben's advice below I thought to try it. the code is straightforward:
var sjcl = require('sjcl-all');
var s = sjcl.decrypt("ThePassword", {
"iv":"IDMkrTa5UH4g0TBCofAcIg",
"v":"1",
"iter":"10000",
"ks":"256",
"ts":"64",
"mode":"ccm",
"adata":"",
"cipher":"aes",
"salt":"lI8kABgvhX0",
"ct":"KfJUrLOmgbn67w2CRYBhcXtX0wdPF3D7ThCKaeZhTymin9hcMD5eLHIUAosmmvfA8npiDIHWgvdbHAk"
}
);
console.log(s);
but when I run it, it pukes with the exception below:
/Users/ekkis/Development/decrypt/node_modules/sjcl-all/sjcl.js:66
c="{",d="";for(b in
a)if(a.hasOwnProperty(b))switch(b.match(/^[a-z0-9]+$/i)||p(new
sjcl.exception.invalid("json encode: invalid property
name")),c+=d+'"'+b+'":',d=",",typeof a[b]){case "number":case
"boolean":c+=a[b];break;case
"string":c+='"'+escape(a[b])+'"';break;case
"object":c+='"'+sjcl.codec.base64.fromBits(a[b],0)+'"';break;default:p(new
sjcl.exception.bug("json encode: unsupported type"))}return
c+"}"},decode:function(a){a=a.replace(/\s/g,"");a.match(/^{.*}$/)||p(new
sjcl.exception.invalid("json decode: this isn't json!"));
TypeError: a.replace is not a function
at Object.decode (/Users/ekkis/Development/decrypt/node_modules/sjcl-all/sjcl.js:66:438)
at Object.decrypt (/Users/ekkis/Development/decrypt/node_modules/sjcl-all/sjcl.js:65:473)
at Object. (/Users/ekkis/Development/decrypt/buff.js:3:14)
at Module._compile (module.js:571:32)
at Object.Module._extensions..js (module.js:580:10)
at Module.load (module.js:488:32)
at tryModuleLoad (module.js:447:12)
at Function.Module._load (module.js:439:3)
at Module.runMain (module.js:605:10)
at run (bootstrap_node.js:425:7)
so it complains that the json isn't json. but it looks fine to me! any help greatly appreciated

Answer 1

This encrypted JSON blob is produced by the SJCL library (https://www.npmjs.com/package/sjcl). A decryption would be done using sjcl.decrypt("password", json_blob). However, if your friend hasn't already been in touch with BitGo [support at bitgo.com], I recommend that route first.