Write a Binding Greeter
APL(Dyalog), 16/20

Losing to GS again...

'⍞,⍨⊂⎕UCS',⎕UCS⍞


This may break the "no cryptography" rule. ⎕UCS is a function to convert characters to unicode code points and back.

Example
First input: Hello
First output: ⍞,⍨⊂⎕UCS 72 101 108 108 111
Second input: John
Second output: Hello John (Note the space before "Hello")



'⎕AV[','],⊂⍞',⍨⎕AV⍳⍞


Similar idea with the cryptography is manually implemented: Convert to/from index of some pre-defined character array (⎕AV) which includes all upper and lower alphabets.