▰▰▰▱ SHADOWRUNUNOFFICIAL // 2057 / CHARACTER GENESIS
Matrix

IC & Host Design

The GM's side of the Matrix: the IC that guards a system, and how to build the system itself with VR2.0's Security Sheaf. Pairs with Matrix Mechanics (the player side). Sources: SR2 core IC (pp. 169–171); Virtual Realities 2.0 host design (pp. 16–19, 60–62).

// HOW THIS PAGE FITS

A decker's actions raise a hidden Security Tally; this page is how you decide what the host does as that tally climbs. Build a host here by hand, or let the Host Builder roll one up for you.

// IC — INTRUSION COUNTERMEASURES

IC ("ice") is a system's guard programs, in three escalating classes by how much they can hurt the intruder. (SR2 pp. 169–171)

// WHITE IC — blocks & finds (non-lethal)

Access
Guards the door — checks whether your persona belongs and slams it shut if not.
Barrier
Walls off a node; you must break through to proceed.
Scramble
Encrypts protected data — and can destroy it if you force the lock badly.
Probe / Tar Baby (VR2.0)
Probe inspects suspicious icons; Tar Baby tries to jam/crash an attacking utility.

// GRAY IC — attacks your deck & programs

Killer
Damages your persona directly — boxes on your MPCP Condition Monitor.
Blaster
Crashes your MPCP and can permanently fry chips in the deck (costly real-world repair).
Tar Pit
Crashes and erases one of your utility programs — you lose the software, not just this run.
Trace (& Report / Dump / Burn)
Locates your physical body, then escalates: report you to security, dump you offline, or "burn" you on the way out.

// BLACK IC — attacks the person (lethal)

Black IC reaches back through the datajack and assaults the decker's brain with biofeedback — real Physical (or Stun) damage to the body. It can knock out, kill, or fry the deck, and it makes jacking out dangerous ("Hanging Tough": Willpower Test vs the IC's rating to escape without a jolt). VR2.0 adds non-lethal and psychotropic Black IC (which scrambles the decker's mind instead of killing). (SR2 p. 171)

// VR2.0 EXPANDS THE LIST

Beyond the core types, Virtual Realities 2.0 adds Crippler, Data Bomb, Ripper, Sparky, Worms, Trap IC, full Trace mechanics (Trace Factor / hunt & location cycles), and advanced/optional IC (Cascading, Expert, Constructs, Party IC). The set above is the runnable core; pull from VR2.0 when you want variety.

// HOST ANATOMY — RATINGS

A VR2.0 host is a color (Security Code) plus five subsystem ratings, one per kind of decker action. Written Color-SecurityValue / Access / Control / Index / Files / Slave — e.g. Orange-6 / 5 / 6 / 5 / 7 / 6 (this host guards its Files hardest). The color sets how fast and lethal it reacts: Blue < Green < Orange < Red. (VR2.0 p. 16)

// THE SUSPICION ENGINE

Detection Factor
The TN you roll against to notice the decker = (their Masking + Sleaze) ÷ 2, round up. Stealthier deckers are harder to catch.
Security Tally
On every decker action, roll the relevant subsystem rating vs their Detection Factor; add your successes to the tally. It's hidden, it only climbs, and it drives the Security Sheaf below. (VR2.0 pp. 18–19)

// BUILDING A SECURITY SHEAF (step by step)

A Security Sheaf is a pre-written list of "at tally X, this happens." Build it once in prep and the host runs itself. (VR2.0 p. 62)

  1. 01

    Rate the host

    Pick the color and the five subsystem ratings (Access/Control/Index/Files/Slave). Crank the ones the host most wants to protect.

  2. 02

    Roll the trigger-step gaps

    The color sets how often the host reacts — lower color bites sooner (gap = tally points between steps):

    ColorGap between trigger steps
    Blue5–7
    Green4–6
    Orange3–5
    Red2–4
  3. 03

    Assign an event to each step

    At each step, name an IC program (with rating) and/or an alert escalation. Early steps trace quietly; later ones get nasty.

  4. 04

    Set the alert tiers

    No Alert (quiet, trace IC only) → Passive Alert (IC toughens) → Active Alert (everything fires; optional shutdown clock that dumps anyone still inside).

// SAMPLE SHEAF

At tally…Event
3Probe-5 IC (starts sniffing)
7Trace-7 IC (begins locating the decker)
10Killer-8 IC · Passive Alert
13Black IC-6 · Active Alert · shutdown clock

// WORKED HOST + RUN

// KNIGHT-9 ARCHIVE — Orange-6 / A5 / C6 / I5 / F7 / S6

Sheaf (Orange gaps ≈ 3–5): 4 Trace-6 · 8 Killer-6 + Passive · 11 Active + Killer-8 · 15 Black IC-6 + shutdown.

  1. Decker (Masking 4 + Sleaze 5 → Detection Factor 5) logs on. You roll Access 5 vs DF 5 → 2 hits → Tally 2.
  2. He searches the index → you roll Index 5 → 1 hit → Tally 3.
  3. He reads the file (Files 7!) → you roll 7 dice → 2 hits → Tally 5 → crosses step 4 → Trace-6 wakes.
  4. He downloads → 3 hits → Tally 8 → Killer-6 + Passive Alert. Cybercombat.
  5. He has the loot at Tally 8; smart play is to jack out before Tally 11 (Active) and 15 (Black IC). The host never had to "decide" anything mid-scene — the sheaf did it.
// SKIP THE DICE — USE THE TOOL

The Host Builder does all of the above in a few clicks: pick a color, set subsystems, and it rolls the trigger-step gaps, stocks IC, and prints a ready-to-run host card with its Security Sheaf.

// CAVEATS & FLAGS
  • This is the VR2.0 host-design core (subsystems, Detection Factor, Security Tally, Security Sheaf). Omitted: full VR2.0 deck/program construction, frames, and Universal Matrix Specs / sculpted-system metaphors.
  • IC ratings on a sheaf are the GM's call; tie them to the host's Security Value and color for consistency.
  • For the deepest version (granular Detection Factor tables, the full IC roster, sculpted hosts), go to Virtual Realities 2.0 directly.