Authenticity Boundary

Why Padding and Hashing Matter

State the boundary between toy arithmetic and real protocols. This is toy arithmetic only, not deployable security.

Example

State the boundary between toy arithmetic and real protocols.

highlighted = computed this step

Step 1 — Raw RSA

Compute the highlighted cryptography value.

raw RSAmalleable toy arithmetic\begin{array}{c|c}\text{raw RSA}&\hlmath{\text{malleable toy arithmetic}}\end{array}

Step 2 — Missing pieces

Compute the highlighted cryptography value.

missinghash, padding, protocol checks\begin{array}{c|c}\text{missing}&\hlmath{\text{hash, padding, protocol checks}}\end{array}

Step 3 — Verdict

Compute the highlighted cryptography value.

verdictnot deployable\begin{array}{c|c}\text{verdict}&\hlmath{\text{not deployable}}\end{array}
cryptography The values in this lesson are deliberately tiny so every modular arithmetic step can be checked exactly.