Wide Mouth Frog

Simplest key exchange protocol. Alice and Bob share secret with Trent.

AliceTrentBobencryptsenddecryptencryptsenddecrypt (got session key)AliceTrentBob
  1. Alice
    1. Concatenates:
    2. Timestamp
    3. Bob’s name
    4. Random session key
    5. Encrypts message with key shared with Trent
  2. Trent
    1. Decrypts message from Alice
    2. Concatenates:
      1. New Timestamp
      2. Alice’s name
      3. The random session key
    3. Encrypts message with key shared with Bob

P.S. Not sure why it is called wide-mouthed frog, could it be this child’s story?

Story

There was once a wide-mouthed frog who decided to venture from his pond and go in search of friendship. He leapt off through the grass until he came across a large black and white stripey animal with a handsome mane and four spindly legs.

Wide-mouthed frog: (Stretch mouth out with fingers and adopt adorable frog voice) Hello, I’m a wide-mouthed frog, who are you and what do you eat?

Zebra: (normal mouth, slightly horsey voice) I’m a zebra and I eat grasses and plants.

Wide-mouthed frog: (Stretch mouth out with fingers and adopt adorable frog voice) Oh, that’s nice.

He hopped off hoping to meet someone who would share his enthusiasm for eating insects. Eventually he came across an enormous bird with talons as pointy as knitting needles.

Wide-mouthed frog: (Stretch mouth out with fingers and adopt adorable frog voice) Hello! Who are you and what do you eat?

Eagle: (normal mouth, squawky voice) I’m an eagle and I eat little birds and mice.

Wide-mouthed frog: (Stretch mouth out with fingers and adopt adorable frog voice) Oh that’s nice.

The wide-mouthed frog wasn’t really so sure about that though, so he boinged away and continued to leap until he came across a bearded white animal with kind, curious eyes.

Wide-mouthed frog: (Stretch mouth out with fingers and adopt adorable frog voice) Hello! Who are you and what do you eat?

Goat: (normal mouth, gruff voice) I’m a goat and I’ll eat all sorts. I especially like shoes and old car tyres though.

Wide-mouthed frog: (Stretch mouth out with fingers and adopt adorable frog voice) Oh, that’s nice!

The frog leapt away feeling slightly puzzled by the goat’s food choices, but didn’t like to judge. He finally stopped when he came across a large, scaly green animal with lazy eyes and fearsome teeth.

Wide-mouthed frog: (Stretch mouth out with fingers and adopt adorable frog voice) Hello! Who are you and what do you eat? Alligator: (normal mouth, deep voice) I’m an alligator and I eat wide-mouthed frogs

Wide-mouthed frog: (turn mouth into very small ‘o’ and adopt high-pitched voice) Oh! How nice, you don’t see many of them around here, do you!

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