include builtins/mpfr.e

mpz n = mpz_init("9516311845790656153499716760847001433441357"),
    e = mpz_init("65537"),
    d = mpz_init("5617843187844953170308463622230283376298685"),
    pt = mpz_init(),
    ct = mpz_init()

string plaintext = "Rossetta Code" -- matches C/zkl
--                 "Rosetta Code" -- matches D/FreeBasic/Go/Icon/J/Kotlin/Seed7.

mpz_import(pt, length(plaintext), 1, 1, 0, 0, plaintext)

if mpz_cmp(pt, n)>0 then ?9/0 end if

mpz_powm(ct, pt, e, n);
printf(1,"Encoded:   %s\n", {mpz_get_str(ct)})

mpz_powm(pt, ct, d, n);
printf(1,"Decoded:   %s\n", {mpz_get_str(pt)})

integer size =floor((mpz_sizeinbase(pt,2)+7)/8)
atom pMem = allocate(size,true)
integer count = mpz_export(pMem, 1, 1, 0, 0, pt)
if count>size then ?9/0 end if

printf(1,"As String: %s\n", {peek({pMem,count})})

{pt, ct, n, e, d} = mpz_free({pt, ct, n, e, d})