Cryptography Reference
In-Depth Information
On November 25, Zimmermann, who was regarded as “pro-
U-boat,” was appointed to succeed him. In an effort to nullify
or at least to reduce U.S. intervention in Europe by engaging
U.S. arms and energies elsewhere, Zimmermann planned to
embroil the United States in war with Mexico and Japan. In
pursuit of this goal, on January 16, 1917, he sent a secret tele-
gram in code (through the German ambassador in Washington,
D.C.) to the German minister in Mexico, authorizing him
to propose an alliance to Mexico's President Venustiano
Carranza. The offer included “an understanding on our part
that Mexico is to reconquer her lost territory in Texas, New
Mexico, and Arizona.” Carranza was also asked to “invite the
immediate adherence of Japan.” Intercepted and decoded by
British Admiralty intelligence, the telegram was made available
to President Woodrow Wilson, who caused it to be published
on March 1, 1917. In convincing Americans of German hostility
toward the United States, the Zimmermann telegram became
one of the factors leading to the U.S. declaration of war against
Germany five weeks later.
Zimmermann lost office just after the fall of Bethmann
Hollweg's government in the summer of 1917 and never held it
again. He died on June 6, 1940, in Berlin.
the art with which the principles are applied. In present-
day cryptanalysis, however, mathematics and enormous
amounts of computing power are the mainstays.
Cryptanalysis of single-key cryptosystems (described
previously) depends on one simple fact—namely, that
traces of structure or pattern in the plaintext may survive
encryption and be discernible in the ciphertext. Take,
for example, the following: in a monoalphabetic substi-
tution cipher (in which each letter is simply replaced by
another letter), the frequency with which letters occur in
the plaintext alphabet and in the ciphertext alphabet is
identical. The cryptanalyst can use this fact in two ways:
first, to recognize that he is faced with a monoalphabetic
