Caesar / Substitution Cipher Tool implementation

Binding contract

This record describes what an executable surface must bind and validate. It does not claim that a public calculator, package, or production route is deployed.

Record owner

Guth Instruments

Lifecycle

verified-clean

Evidence ID

t5-099

Effect

Computation or source lookup only

Input and validation requirements

An incomplete 25-character substitution alphabet causes a lookup outside the defined mapping: encrypting Z produces an undefined result. The tool should reject this input instead of returning malformed ciphertext.

Required corrections

No binding erratum is attached to this unique-name record. Implementers must still preserve the declared units, domain, and failure behavior.

Inspectable interface fixture

The sample below is evidence for interface and validation tests, not a production implementation.

{
  "inputs": {
    "mode": "caesar_encrypt",
    "text": "MEET ME AT 9",
    "shift": 3
  },
  "expected_outputs": {
    "encoded_text": "PHHW PH DW 9"
  },
  "working": "M=12: (12+3) mod 26=15=P; E=4: (4+3) mod 26=7=H; E=4: (4+3) mod 26=7=H; T=19: (19+3) mod 26=22=W. The second MEET becomes PHHW. M=12 -> P=15; E=4 -> H=7. A=0: (0+3) mod 26=3=D; T=19 -> W=22. Spaces and 9 are unchanged. Result: PHHW PH DW 9."
}

Other records

Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

• VERIFIED_LEDGER.json
• evidence-tranche5/tranche5-results.json