The transcript hash is recomputed from the ordered toy values.

highlighted = computed this step

The hash covers those values

The toy hash reads the ordered transcript values and reduces them modulo 97.

Hmod97H\bmod{}97
Transcript hashToy TLS transcript rows are recomputed from DH and certificate pins.Transcript hash - hash=43itemvaluecheckClientHello4pinnedServerHello9pinnedCertificate digest33root signatureServerKeyShare19DH publicClientKeyShare8DH publicTranscript hash43weighted mod 97Shared secret2DH recomputeClient Finished64toy checkServer Finished70toy check

The inputs are visible

The table shows hello values, certificate digest, server share, and client share before the hash row.

values before hash\text{values before hash}
Transcript hashToy TLS transcript rows are recomputed from DH and certificate pins.Transcript hash - hash=43itemvaluecheckClientHello4pinnedServerHello9pinnedCertificate digest33root signatureServerKeyShare19DH publicClientKeyShare8DH publicTranscript hash43weighted mod 97Shared secret2DH recomputeClient Finished64toy checkServer Finished70toy check

The hash row is recomputed

Weighted reduction gives transcript hash 43.

H=43H=43
Transcript hashToy TLS transcript rows are recomputed from DH and certificate pins.Transcript hash - hash=43itemvaluecheckClientHello4pinnedServerHello9pinnedCertificate digest33root signatureServerKeyShare19DH publicClientKeyShare8DH publicTranscript hash43weighted mod 97Shared secret2DH recomputeClient Finished64toy checkServer Finished70toy check

Summary

Changing a transcript value or its order would change the recomputed toy hash.

hash row is checked\text{hash row is checked}
Transcript hashToy TLS transcript rows are recomputed from DH and certificate pins.Transcript hash - hash=43itemvaluecheckClientHello4pinnedServerHello9pinnedCertificate digest33root signatureServerKeyShare19DH publicClientKeyShare8DH publicTranscript hash43weighted mod 97Shared secret2DH recomputeClient Finished64toy checkServer Finished70toy check