Generating Random String from Text in Cells

Originally Posted by yudlugar

=LOWER("g4a"&MID(CONCATENATE(A1,B1),RANDBETWEEN(1,LEN(CONCATENATE(A1,B1))),1)&MID(CONCATENATE(A1,B1),RANDBETWEEN(1,LEN(CONCATENATE(A1,B1))),1)&MID(CONCATENATE(A1,B1),RANDBETWEEN(1,LEN(CONCATENATE(A1,B1))),1)&MID(CONCATENATE(A1,B1),RANDBETWEEN(1,LEN(CONCATENATE(A1,B1))),1)&MID(CONCATENATE(A1,B1),RANDBETWEEN(1,LEN(CONCATENATE(A1,B1))),1))

Assuming the first name is in A1 and last name is in B1

Just tried this and it did the trick! Thank you!

To get use each character only once I can't get it in a single cell formula but I think this works:
A1: first name
B1: last name
C1: =LOWER("g4a"&MID(CONCATENATE(A1,B1),RANK(D1,D1:Y1),1)&MID(CONCATENATE(A1,B1),RANK(E1,D1:Y1),1)&MID(CONCATENATE(A1,B1),RANK(F1,D1:Y1),1)&MID(CONCATENATE(A1,B1),RANK(G1,D1:Y1),1)&MID(CONCATENATE(A1,B1),RANK(H1,D1:Y1),1))
D1: =IF(COLUMN(A1)<LEN(CONCATENATE($A1,$B1)),RAND(),"")
Then copy D1 across the row to whatever is a sensible limit for maximum characters in a name (say to BA1...)