Klartext-Geheimtext-Angriff

Zu dem Geheimtext

UYSMS  ZNZGC  MBOVF  YJVOK  SBRNM  ISFIA  VVGKM  QDFAZ  YGFIG
KVRNR  YSRTU  RLZEL  FIGWS  EFYCX  IFUSI  DEGUY  SCEZF  KWWIZ
JCZSS  ATFTN  SYMRF  CEEFS  SSRTS  VHEVA  FUHYE  ZFIWM  EAURL
ZELFI  GNYRU  FASWG  BBSCG  BSISM  XRESM  DLRNR  QRMAF  J

gehört der Klartext

THE COMMISSIONER OF INTERNAL REVENUE SAID COMPUTERS ARE
MAKING TAXPAYERS MORE HONEST BUT AT THE SAME TIME
MILLIONS OF DOLLARS ARE BEING RETURNED TO AMERICAN TAXPAYERS DUE
TO MISTAKES CORRECTED BY THE MACHINES

Zu ermitteln ist jetzt also das Verschlüsselungsverfahren und der verwendete Schlüssel.