Experiment #1
Method of reversing the transposition: this is the K4 text after simply removing “Kryptos” letters as a process of elimination
Transposed text:

OBUOXOGHUL
BSOLIFBBWF
LRVQQPRNGK
SWTQSJQSSE
KZZWATJKLU
DIAWINFBNV
TTMZFPKWGD
KZXTJCDIGK
UHUAUEKCAR

Playfair cipher: no keyword, kryptos, hydra, lhydra, medusa

MD TP YN FG QP
CR NP HK BB VG
MQ QL UL SM FI
RX SU TH UR UC
EU YV DQ HI PQ
YD BV HO GA LX
TT PW KL GZ IB
EU YS HD YD FI
SK QE PZ HE BQ

then

CA IK UB FG VI
AO SI MD BB MA
EV ZL NT PL DP
AV ZH OL LC RS
TU XV CY DU IV
OD YM QM GA LX
TT QW GY YU FH
TU ZP QO OD DP
ZD WO VD TO SY

then

IH OI US BA WI
FO QI MB BB XE
MD WP PO AM CN
QX SP OM PQ QF
NV XV ZN NI IW
HL DZ NM EG KZ
TT NX CS LV EA
NV ZS KB HL CN
OU ZH WB CY RD

then

PA OG US IL OU
EP GU NB BB ZC
RD WP PO ZF NI
QX SP PM PQ MD
NW XV FO GI UO
HM CU GM EA IZ
TT NX BT CQ ML
NW ZS KB HM NI
VL OL XA CY FL

then

PA MR VQ AN YF
GE RH LB BB YB
FL XO PO TL CN
EZ RP EN TD UM
NX YV GO HI FY
EK BV HL CA HZ
TT SV BR IX CS
NX ZQ KB EK CN
ML MF DM CD FO

Bifid cipher: no keyword, kryptos, hydra, lhydra, medusa

OT BI RZ NQ YP
LT GI FL UW MD
CH RL LR NC KQ
ID DI CG ZK GA
NE RK ZB RB QD
MZ UK PN II GY
QN VI RT RB RP
IU RC TP QL DZ
FZ WZ VX VF DB

then

OT BI UK BR ZI
AK GI EW ZY NO
BN AA SP NB QR
DH OQ BM ZH FF
IB KO ZA MX MU
KI TC QN DQ PK
SC WD PU MX OO
QK MZ CO SA HO
YR UU VZ VF OE

then

SA EH WY QD ZO
OD EU HA ZD LI
EA PS PH LN NY
FT FA ER ZN CS
MK DP ZE PN OL
QC AT NX FZ LB
PP UL QU PN QP
NH OI TO OT GI
KE WV VV UN HX

then

SR CB WY OL ZO
OD KH HA ZY YH
CF PT PH YR NB
EZ EF CE ZN BZ
DH YW ZC QG OM
QC RZ NX MR KI
PQ UM QV QG QQ
NA OI TO PO FO
IM WW VW VG AR

then

RS CB DQ QU VL
OD CW IM SP KP
CG EY PE KT NA
FT FG AA ZG BR
LP QQ ZE PN OK
QC TT NX FZ KI
EX VC QW PN DX
HF QH MY EV MF
HI XX WX WA FU

Four-square cipher: no keywords, kryptos-kryptos, kryptos-hydra, kryptos-medusa, hydra-medusa

M D T P Y N H G Q P C R L O F I B B V G M Q V Q U L S M K G
R X Q T T H S Q U C K Z W Z D Q K I P Q D I B V H O G A L X
T T P W K L G Z I B K Z Y S H D D I K G S K Q E U E H E B Q

then

I F V F V I P O W Q G I G Q S L I I X N R B Z R T E D R L D
H W E U F R R K G M E V X Z K C Q A Q W L Q H X T Q O H R Y
E E U X O C C V L O E V Z D U F L Q L D Z L X F W L E F G C

then

F F V Q V T L D X L I T H L T F F I Y H T B X R R U E M M O
H W C U F M T U H G E V X Z K S R L Q W L L H X U L L H R Y
E U U X M S C V N D E V Z T R F L L M O V A Z A X F B F I C

then

G F V Q V T L O Y L K D I L T F G I Y H T R X R R U E M N O
G W C U G M U E G B E V W Z K S S L T B M L G X U L M H Q Y
E U U X M S B V N D E V Z T S F M L N O V L V F W A C F I S

then

R F V Q V T F P Y L K A T L O F G F Y H O S X R R S E O H P
R Y S U R O U C R D P W W Z E U N L O C B N B Z P L G I L Z
U U P Y G T M W H E P W Z T N F B N H P V L V F W A N G D U

Ultimately I didn’t expect a solution to pop right out because that would mean someone could have forced a partial digraphic substitution solution at any time.

Experiment One failed to provide a solution or partial solution but was a successful test of the method.

–Kryptosfan