# Cryptographer's Anthem

### Lyrics [pdf]

 A A_2 ;A B E Oh, say, PGP, and R S A publ ic k ey
 A A_2 A E A B E Crypto syst ems are simple, with primes $q$ and $p$;
 A A_2 A B E Call the product of one less than each of them $k$
 A A_2 A E A I pick $d$ and $e$, whose product is $1\bmod k$.
 A A_4 A A_4 A E A E7 Now I just publ ish $d$, and the prod uct $qp$,
 A A_2 A E7 A B E You raise $d$ to the power of message block $b$;
 A E A EA DE A E Take that modul o $pq$ and send it to me .
 A E A D A E A D E7 A And I'll use it as the exponent of priv ate key $e$.

 Now this program can fit into three lines of code,
 Using perl and dc, though the logic's distorted.
 Cryptographic machines are a weapon of war,
 And the government says they must not be exported.
 Make a barcoded card, or if you are a bard
 run the code through a modem, it's not very hard.
 \spoken{\quotation{
 Now, if I were being mean I'd stick some modem tones in here}}
 Then this song would be a munition, its music you could never take
 From the land of the free, and the home of the brave.

The description of the RSA public key crpytography algorithm is mathematically accurate; though it's worth noting that any practical implementation will do the exponentiation and modules in a single operation. Perhaps the only obscure point occurs when specifying that $de \equiv 1 \bmod (p-1)(q-1)$. The twisted phraseology that defines $k$ as $(p-1)(q-1)$ is particularly kludgy, but what the hell, it scans.