Unknown method problem

38° 53′ 42″ N, 77° 02′ 12″ W

February 11, 1923

My dear husband,

The BOI gave me encrypted secret messages.
I am in charge of deciphering them. I have one or two ideas,
but I would like to have your opinion. Unfortunately, the BOI
did not provide me any information,

With love, Elizabeth

NR001 0950Z KKPIN BDJDM AEWUS XWYSC YDWIT WVIFJ DGQYG ALAZK

YXPES BGNXL CYDBX HVNDJ HMRVE QGKWK OBBLR DYCSR ZFKNG FVMIM

TOTWW JDBOG EPGZW FAMVC LBGVY CTJGC FWAQQ YIIGY PCFWD WDCEA

QKWUT XRKRF YDWIT KKPIN

NR002 1010Z KKEIN DZIRS ZPCXL DGDYJ AQXWV EJGJU ZHQMB CYECT

MDFHK UWLNJ VBVRW EBMLF XDGHC IBMGH BCTPR SJSGW MUEHN WINGD

YWGNN KDJBP VBUDK YEBKG QZTSD XCYBH CMBRS BICVB YWYIU GYWFD

WICUB ZZWBU TLAAV XYOYU RSAPB HRGRO GYFHJ EMQUQ UEVJL XBDLP

CDLAE JKDDG HXMZZ KKEIN

NR003 1045Z KKZEN QUSCT DTNVD BAVRW XAXAL QGJAM YRUFE JQFVU

FNMDE LXSCB XORZC YYUQV CPGUC SQVVR JKQDU USPNO VYBRY QYIHL

OWQSV TUCDA GKLAA ERCDN WTYJG HDPRK VIAVH QAMXP OMZCO NNPSS

FLONQ ECUEK FGMMF GWHRK QNSCT COACG ETUSW KTGXX AQXHR EYZUI

AIGQS PYQVJ TLXVC NSPWH WYOXM KKZEN

NR004 1111Z KKHEV CMMXX FUFYH HIPYP BODZH CSSRM HMVWY FDMKR

OLZSJ YQVAI DXHQC TEDVT SXABO LYJAY UGYVH QUWZS QIYPL MHLJG

TCZVZ IKCWM DFMPU GCCXF ZPXIW YGPDS OPYNX DERSM TOUJQ PTYBX

ZCJLB ZXJNL WCFXI XUGXI XYLFH ICBWI XZKSD CWCQO SMLFN FUOGM

WZSGT CZZID LOSXV QUYXS ZZFXU PGCVR KQKZR ZRQWN ETIYU UCJQD

LBIOV EHPSR TYKPG ZTKQY USNEU ULMQX LELFQ EAGRY RCZZZ KKHEV

NR005 1130Z KKGIN HKCZH AUNON BYJDT LCTTB WVSZO XAYHR OEZBJ

IHOUM QNOUE STTCY OGYBI YGRCG NZTBT GACTV GLDYI BPEGK FQHNF

BMGDD JUTLJ UEQIH SBRBU RDWEU XFMGH JJBAN WRGTG YSNGL LBLQD

BXMCT JHGMO USUTV IJDBB LFSFX FRVFD CLLJI ZLDUK YTWLK EIXHD

XBRYW DZZZZ KKGIN

NR006 1155Z KKGEV CGSNN OKWHH IPNQG ITBKB UQCHP QTSGR NZSLH

LARON KYDAK YCGCB QNPCI CVGGL FDQKZ VGZSO GXKZZ PWQMM BXAGV

XYOAB RUVNU IUWCS DZBMN DWFQG HTYYZ VJRGF IOIDG FCVQY TMDUO

XNLYZ AYUGK THRNP IECQL BBPXC NTKQM ZPDHQ LXDGL TTUZQ URHFH

WWCTL NZDBD GANPT UCDHY UUDMM CENCL YXJCP WEWCZ TRLGS YMLBB

PUBNZ KKGEV

NR007 1212Z KKRIV FYZQQ HTHST XGTNM AICMX ZVVJC NZKFW HXIMA

YCBEN XORKM NIZIB HCKZD QNNET CJCXW NDAMA KIOZE NHFWY EDQMH

GTWPL UGGZT ZOFZD IEMKC WWKVH TEGUZ KHFTJ KKKZB CDKKB KWHAY

LSMOJ FNFND AAIKT EOYEL JNWQC LMSXC UMHYO AJYFK JPGDO HYLNN

KYNDI FTMHE ZSJMN WRZSF PCAVA DNNNL ASJQE CONKW XABKK WZCLV

IHJQH HBVGF KNFNM EGMXF ZEULX KZDAC YHUGL SKXWT YTYBB FZSBA

FYBAZ UNFNS JTBHO NTOTK TRCDO KXTKQ MCNUT KJNFU KKRIV

NR008 1222Z KKQEN JBWON VOJZX RBWMG FISFU GVCUW OOEYO RFCGG

GYYYV FSVGI TLLSU XWHTM WPHEL BAYFY FAAWJ MVPZY NOUHU MOQSR

QOXYB JJOAX FPOVZ ANXSC BQSNZ AHEYI BWMGZ KKQEN

NR009 1235Z KKAIN MKBZY GUTDW EUXMZ OCEWA EBWUS XWCEE QYZOS

BHGWL MOCTK YUECY ZJPWC LNXTB RBORU PWIDZ ZAGCT AGKFW AQQYM

IJZUR CRFNG FVMNU JUIYR JBKYX FKSZU HXZPZ LBWAN RBOUD WKUEN

MPDDW DJBBU ZJUAM ADCLP YTWZZ KKAIN

NR010 1255Z KKXIN QTMGW AKFYH DSHVR ABRGK DVMOC NKRJU NUUYK

JKFKH GAVDY LPSAM NOJSM EWRCY HCPSD NOHQD JJXJU TLCFT EWZSI

SMGBF SDRHQ ONNUI PLZOF GQJFG BNYHK CBTHX XFUCJ IGBJC LWJII

SFYNR PSEQI FBEOT HJKAC XODJN FECBA GTSLW ZRBEO THJYP IWVGT

BKZBO GXLQI FHLNV IJLJF ZQWXG TWZFF FQRLS TGCLV DZLYJ ALTOR

RYTWB KNUUT NWLPA BWYTC DMUEX UTVBK ZNYJI ILYLB XHAWD XWTAQ

CQDJZ KKXIN