This is an implementation of a very simple version of RSA in TI-BASIC.

RSA.txt

//remember to not type comments when typing the code into your calculator!
//This program is an implementation of the RSA algorithm, using small prime numbers, in TI-BASIC.


ClrHome
{2,3,5,7,11,13,17,19,23,29,31,37,41,43,47,53,59,61,67,71,73,79,83,89,97}->L1
Prompt X
Lbl A
randInt(1,25)->T
randInt(1,25)->W
L1(T)->P
L1(W)->Q
If P*Q<X
Goto A
P*Q->N
2->E
Disp "PUBLIC KEY:"
Disp N,E
(P-1)*(Q-1)->θ
While E<θ
gcd(E,θ)->C
If C=1
Then 
Goto 1
Else
E+1->E
End 
End
Lbl 1
2->K
While(1+(K*θ))/E≠int((1+(K*θ))/E)
K+1->K
End
(1+(K*θ))/E->D
X^E->C
C-N*int(C/N)->V
1->J
For(I,1,D)
V*J->J
J-N*int(J/N)->J
End
Output(1,1,"MSG DATA"
Output(2,10,X
Output(3,1,"ENCRYPTED DATA"
Output(4,10,V
Output(5,1,"ORIG. MSG"
Output(6,10,J

This is giving me a syntax error for some reason. I copy and pasted it perfectly in