The 1924 Navy Challenge, the cryptograms

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The 1924 Navy Test Messages

This challenge is composed of 10 test messages enciphered on the first version of the HCM (Hebern Cipher Machine) which uses 5 rotors. This challenge was solved by Friedman in 1924.

The 10 messages had lengths of 330, 326, 324, 314, 326, 323, 312, 303, and 319 characters. In total, 3209 characters.

The cipher machine

The encryption machine used to encrypt messages is well known to W. Friedman. The American army purchased two copies. On the other hand, the 5 rotors used by the navy are wired differently from those of the army machine. W. Friedman doesn't know the navy's rotors wiring.

The input and output permutations (LFS and RFS) are the same in both models (the Army model and the Navy model).

	LFS: XAKHSZJLYWGPMIOURDBFTNVCQE
	RFS: TYOEUMXDFJQVKWBNSHCILRZAGP

Some helps

We know that all of the messages were encrypted with the same rotors used in the same order.

The indicators.

        1:      A G R A M
        2:      C O B A N
        3:      B L O I S
        4:      A G A N A
        5:      C U N E O
        6:      D O V E R
        7:      G E N O A
        8:      H A G U E
        9:      M O N T E
        10:     N E P A L

Each cryptogram is prefixed with an indicator allowing the recipient to configure the initial position of the rotors. The navy clarified that this indicator actually corresponded to the initial position of the rotors.

Precisely, the first and last letters are the starting positions of the left and right control ratchet wheels, respectively, while the middle letters are the positions or rotors I,III, and V. No starting positions are given for the two stators (II,IV).

Because the problem is very hard, we note that the messages are Naval Attache reports concerning Germany and Japan. As a further hint, the following words appear in the messages:

        ZEPPLIN COMPANY, 
	UNITED STATES,
        ALTERNATING CURRENT.

Note: I don't know if the cribs were passed to Friedman or it was an aid provided by Deavours & Kruh to help readers of their book.

The complete External key

After Friedman successfully deciphered the messages and won the challenge, he asked the Navy for the complete external key to try to find the wiring for rotors 2 and 4.

        1:      A G R R A A M
        2:      C O B B A A N
        3:      B L O O I I S
        4:      A G A A N N A  (AGAANNB [Friedman])
        5:      C U N N E E O
        6:      D O V V E E R
        7:      G E N N O O A
        8:      H A G G U U E
        9:      M O N N T T E
        10:     N E P P A A L  (NEPQAAL [Ellison])

The 10 cryptograms (from Deavours & Kruh)

The navy transmitted the cryptograms to Friedman in the classic way, that is to say in the form of groups of 5 letters.

One of the first things Friedman did was to rewrite the cryptograms in a form suited to their analysis. This is the form in which we present them. This is also the form used by Deavours & Kruh.

Each column of a cryptogram represents a position of the 5th rotor. The messages have been written out for the reader so that the medium rotor is constant along each line of the text. The medium rotor is the rotor in first position (I). The fast rotor is in 5th position (V), the slow rotor is in 3th position (III). For each ligne, whole rotors doesn't move except the fast rotor which is in position V (except if the left ratchet wheel reaches the N value).

The 1st cryptogram

Indicator: AGRAM

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

The 2nd cryptogram

Indicator: COBAN

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

The 3rd cryptogram

Indicator: BLOIS

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

The 4th cryptogram

Indicator: AGANA

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

The 5th cryptogram

Indicator: CUNEO

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

The 6th cryptogram

Indicator: DOVER

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

The 7th cryptogram

Indicator: GENOA

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

The 8th cryptogram

Indicator: HAGUE

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

The 9th cryptogram

Indicator: MONTE

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

The 10th cryptogram

Indicator: NEPAL

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

The 10 cryptograms (from Friedman)

Deavours and Kruh have published the cryptograms that make up the navy challenge. There are several errors. I think these authors only had access to a poor quality copy of the cryptograms.

The messages published by Friedman contain errors but these mainly come from encryption errors made by the navy cipher clerks.

On the other hand I think that Deavours and Kruh had access to the decryptions of the messages. Indeed, the first two letters of the last cryptogram (n°10) begin with “AR” instead of “ZN”. Now the first word of clear is “ARMY”.

The 1st cryptogram

With External key: AGRRAAM

RAW     O P Q R S T U V W X Y Z A B C D E F G H I J K L M N  
CW5     C D E F G H I J K L M N O P Q R S T U V W X Y Z A B

AGRBN g:                                                  J
BHRCO h:N U T X H V Z S L U M L Z X H X H 0 H Y B R C L M S  
CIRCO i:U F C D S U F M O V K C N K Y N N G A U W Y L I Q Z  
DJRCO j:U T L W B Y D G O W K H R X T C J C S V G J J F Y V
EKRCO k:J S R C E Z U Q K D O Y T X V T V C A S N Q P G E C
FLRCO l:A R U C W L D D C U Q D X F L C B K D B E C H X D G
GMRCO m:V A Y E E U Z H W R W V V P V D V M G E N J W V U U
HNRCO n:E N M O Q J P U M V K G W Q C Z W K R I I X M J A C
IORCO o:L N S W E A M I A U U V W V B L E M B O S P X F R R
JPRCO p:S G O W C J L V M H Y A J E Z G F Y B U D A Z L O Q
KQRCO q:U M T Z T O V T B D K W H A C H Y N Y O B N P I H R
LRRCO r:T K S X F G W M N L N G O H Y M K H P G W I E B E L
MSRCO s:A B L Z C J U C L J X S O U D L W U T A F I A R T U
          Key: OSTDP                    Key (final): OTSSE
NTRCO t:S|N G X A Z B O H G W P Y G Z R V

The 2nd cryptogram

With External key: COBBAAN

RAW     O P Q R S T U V W X Y Z A B C D E F G H I J K L M N
CW5     B C D E F G H I J K L M N O P Q R S T U V W X Y Z A

DPBBO p:B J E N F C A D D A Y G K N S F R B H W L U K J P Q
EQBBO q:U Q I S A H S V I H S W D T I D Y A B J G T K K M Y
FRBBO r:X O L D Y N V H C B Q T J O N I Y X J M J D O D T B
GSBBO s:L R K S N Z K M K P X U S U D S O C R J I Y A T X J
HTBBO t:X M R Y W F Z H E B B Z E B X F F W H P F V Y H F V
IUBBO u:B S A G B T A L Z U G G E X A X A K X Y I H H N F T
JVBBO v:D T L L O W U O A I N H N J W Y B P T A Y I D G J B
KWBBO w:N U V J L Y T G F C D N F Q J P L X T J C J R P H K
LXBBO x:Z G G V J M X F M C Z T Q K Z S T F H S W O U D T R
MYBBO y:Z L U P J T Y B G J C P O N X Y A Q Y H H M C W M W
          Key: OZCCP
NZBBO z:Y|B H I W I V O Z H H J K E O W Y I C E A C Y Y O Q
PACBO a:V G W C S F S Z U E N J Q I O P D J F U C U B T O V
QBCBO b:W P Z A Q S T M K G I H G Z

The 3rd cryptogram

With External key: BLOOIIS

RAW     O P Q R S T U V W X Y Z A B C D E F G H I J K L M N
CW5     E F G H I J K L M N O P Q R S T U V W X Y Z A B C D

BLOEO l:          P Z X X O Z W T S R S F F B X K H Y X B Y
CMOEO m:J N I R N L I F K V O R A R B V Z U G V A C C N B T
DNOEO n:Y L P C W T O L Q D V H A Z Z G Z P G J P F E R M Q
EOOEO o:U D P K F K Q E M D S O D L M O K R T D U V C A N L
FPOEO p:Z Q B O R W I U P F H Q O O G X M T M I J M V U B Z
GQOEO q:G A H P N G Q R J F T L S I P N L W C K I E T H I K
HROEO h:O S E R O I B J O P H X S V X G L Y U F Y A E L G K
ISOEO i:O L A L F V E F H R N Z D X I X Z K V B G I Q P M L
JTOEO j:R Y H A Q H Q U G Q X O U K C M P A Q U R N Z E A C
KTOEO k:X N T X I C L R S Z O A A P H B I K S D C H R Y R S
LVOEO l:W W D Y C Q S K K U B J I Q W Q F J H N U K Z U S D
MWOEO m:R I B N W M S C S F M N H Q D U P P U Q L U U R A H
          Key: OXPFP
NXOEO n:X|N G Q E D J M R W X X K R Y S V

Friedman's note:
- (At key JTOOISC), CM should be ZX.
- (At key MWOOITD), UPPUQLU should be PUEDZRK.

The 4th cryptogram

With External key: AGAANNA

RAW     O P Q R S T U V W X Y Z A B C D E F G H I J K L M N
CW5     B C D E F G H I J K L M N O P Q R S T U V W X Y Z A


AGAOB g:                            F S R U X M M F Y E P A
BHABO h:J I U K X J S Q S G Z I R K S R Y L L R D Y C O V Z
CIABO i:O E E K A P N Z R Q B P O S S E P Q D X G D L T N A
DJABO j:O P R R N F O B Z F L C K G M K C L M X L L J H V V
EKABO k:O H U D H V O G A K D I C S C B E Y X M P Y T R D K
FLABO l:K V J D W D O A L J Z C Q N M W T Y U O D Y Z C O E
GMABO m:S N W T S F Y C G P X V R V J C E Y Y V L G W P I P
HNABO n:Y R M K Z O M C L G P C S O Z S C C A N P N X Y W Y
IOABO o:K S K J H L L Z F N Z Q Y S B Z O L T I X M R U J U
JPABO p:Z A M P K Q A D B R B C O R P U G J I H K A J K L K
KQABO q:M G S P E G R E S I F A I X Z Q F I W M A D U C F M
LRABO r:I V D A E S I E U O Z S O B H M Q N W N D U R G O L
MSABO s:B G R U B H C V I Q U A U N G W

Friedman's note: The key as given was in error. It should have read AGANB instead AGANA (Friedman is right).

Friedman's decipherment does not cause any errors. On the other hand I have many incorrect lines.

The 5th cryptogram

With External key: CUNNEEO

RAW     O P Q R S T U V W X Y Z A B C D E F G H I J K L M N  
CW5     E F G H I J K L M N O P Q R S T U V W X Y Z A B C D

CUNFP u:  H K W Z A R R P B Q B I V Y S M P D M Q M V U D C
DVNEO v:E M Z X D P I D L I A W W U B Q M E Z P I X I S N H
EWNEO w:R I Q O W Y I N R C X Y M X H J Z C R H A T H S B Z
FXNEO x:P M L K V O U Z R S A U G O H L T K O U Z J E C X L
GYNEO y:S K D H W B I L E S K S W G Z G P R U I Q L H J J P
HZNEO z:M K D Q E U D K M I G E O J L R Z D K N N P N Y X Y
IANEO a:H N M S S Y W Q D W D K V O B B G L U E B W M Z X D
JBNEO b:W K S A V U E A S U L C O G R Q L Z W U K I K T J Z
KCNEO c:P O W I I X H L J B H F K B W V G G L A G G Y I C Y
LDNEO d:V C J A B X N D I W C C E M H G K Q Q D C B I G R I
MENEO e:A Z E H O F O R Z F F J O N F I V S M O Q W T Z I S
          Key: OFOEO
NFNEO f:W|Z L I E U E Y Z P B Q E Z I Q G O P L V W B T I X
PGOEO g:H Q B X R Z S I V Z M C S P Z

Friedman's note: Portions (of text) are incorrectly enciphered.
(At key: DVNNEZS), cryptogram: XISNHRIQO, Friedman's decipherment: DOUTTOHIM.
(At key: JBNNEYI), cryptogram: KIK, Friedman's decipherment: ION.

The 6th cryptogram

With External key: DOVVEER

RAW     O P Q R S T U V W X Y Z A B C D E F G H I J K L M N  
CW5     B C D E F G H I J K L M N O P Q R S T U V W X Y Z A

DOVFS o:        L P I O U E Z K S J B X C A F E U K S D W H
EPVBO p:R Y S N W A N I P U J M Z A H O U Y V U V O E C N B
FQVBO q:S M P N L Q A P T A G G V H R M Z V B N Z I I X P B
GRVBO r:O L Y X B S S M B W L H V X V S P Z I K O G O O C C
HSVBO s:F E K X M R A L N V R S K A E S D S M T G R X S Y P
ITVBP t:S M G S G Z B V D E N W Z S I V J E S V W Y J R G X
JUVBO u:E P I X V E J E B H I F G S V P X X G A Z C Q C Z S
KVVBO v:F R I V W W D G V A H G H Q L V L M V B U S W X Y Z
LWVBO w:H N W W T N K V B Z U Y R T P M R W P I C V Q Z P D
MXVBO x:N X C E W Y R M H D W N P Z L W C C N X W T L V K G
          Key: OYWDQ
NYVBO y:L|P E N T M E G L C U M E V K H Z Y N A H D S T J L
PZWBO z:D H J B N I Q W N W A T I T L S J F U A R Y N W L E
QAWBO a:F K O S P S C F A Z W S N T Q Y B X Q M G G V A N

Friedman's note: Portion (of text) was incorrectly enciphered.
(At key: PAVWEDQD), cryptogram: YBXQMGGVAN, Friedman's decipherment: REMARKABLE.

I was unable to correctly decrypt the text from key MXVVEFS to key NYVWECP (22 characters).

The 7th cryptogram

With External key: GENNOOA

RAW     O P Q R S T U V W X Y Z A B C D E F G H I J K L M N  
CW5     C D E F G H I J K L M N O P Q R S T U V W X Y Z A B

GENPB e:                          B Y P F M L W Q Y S D Z U
HFNCO f:W X Q G M G X N K T R V K V T T B Y T P V D Z T N N
IGNCO f:N R O T L D H S W W G M I P B Z Z C G P G P R V T B
JHNCO h:M B Y B U Q Q O U R Q D M D B N E Q D S B H Y C Z J
KINCO i:X S J R L I G G D J D V A T H Y W R U W X L B Y Y I
LJNCO j:L J Y V T N D B Q T Z W H X D Q C C G M O U R Y X W
MKNCO k:C T B J P N R M F F O V L Z Q D V B Z Q A T O C Q Z
          Key: OLODP
NLNCO l:E|W D K L W H H P V W A U T U N K A E I S J T B Z P
PMOCO m:I L L V M K Q B O Y X J M H U K F H B G X S A H Z O
QNOCO n:O I Q N M G M O G Y B W U H Y F K O T S P L I B O F
ROOCO o:E W K D Y A D X Z S N X L J Q W O S K U R L E O G L
SPOCO p:S V Z W W G O Y Q C W J S A D P S O Q U Y H D S U R
TQOCO q:S E N X T M F T Q Y L O S W U M J L P V A Q K T

Friedman's note: Portions (of text) were incorrectly enciphered.
- (line at key KINCO). - (line at key ROOCO).

The 8th cryptogram

With External key: HAGGUUE

RAW     O P Q R S T U V W X Y Z A B C D E F G H I J K L M N  
CW5     E F G H I J K L M N O P Q R S T U V W X Y Z A B C D 

HAGVS a:                                  S Y Y G S T X V P
IBGEO b:M A G V Q J T A R Q R M F L A H W T Z L B H T V D R
JCGEO c:O H H B H P D Q N T K Q Q H S F J M C F O J A A M K
KDGEO d:W Y S X V B I W O A J Z G Z E J A D C K W Z K R I I
LEGEO e:T I N O V U O Z P Y L H T Y S R P W G L R V Y F G B
MFGEO f:A I H P U C B R K O Z U G C C H W Z D I X G R B A P
          Key: OGHFP
NGGEO g:Z|G C U N V K U A T D Y X V E K N W Y X R V P D W K
PHHEO h:G U X J B X E O D S P Q S A X A O Z M B V K F G M G
QIHEO i:Z I F O D O F Z I F T E L V M U D C B V P O P T N O
RJHEO j:A G I N K L B W V X J V C V Z Y K A W O P T E C P Y
SKHEO k:C U W I I J K B Q P W O T H S G L S Y D F Q U Q N J
TLHEO l:V R Q G B S N J H B S P X Q V S U M H K W Y I B C Y
UMHEO m:H O W F V F J N N A U J F L S C O

Friedman's note: Portion (of text) represents error in enciphement.
- (From JCGGURB key to JCGGUDN key [13 characters]).

The 9th cryptogram

With External key: MONNTTE

RAW     O P Q R S T U V W X Y Z A B C D E F G H I J K L M N  
CW5     D E F G H I J K L M N O P Q R S T U V W X Y Z A B C 

MONUF o:                                  H D R Y Y Z Y T O
          Key: OPOEP
NPNDO p:U|J J S L S W C R N U L S A E X T G W P Z Y V G I V
PQODO q:C B X Y R K R H N Z Z W J A Y Y N R Y V F Z J S K G
QRODO r:O V D U Q Z T H H S Y G E G K O A Q F Z H X R P M H
RSODO s:Y Z T J L I U N X X U J A I V S S T F X T Z L J V U
STODO t:V E Y Y G O D Z L N M L V K U O F R X H V K I H P F
TUODO u:L N C E L F Q F S Q Z S W H L E H D T G S B U H E T
UVODO v:U Z A C A M H V P D J Z K I F A J G V O R H X O D J
VWODP w:S J B U S K B H H F N I B Y X Y X D I H L K E H Q J
WXODO x:E L C H U K F N C O Z D Y C K T Y P Q P C D C H O M
XYODO y:U L Z P O A T X I T V K T C K N B T Q J E V O D G G
YZODO z:C U Z Q W D V W Q X Z E N E Q E S H C E C L U H P S
ZAODO a:H E X G E K O E

The 10th cryptogram

With External key: NEPPAAL

RAW     O P Q R S T U V W X Y Z A B C D E F G H I J K L M N  
CW5     D E F G H I J K L M N O P Q R S T U V W X Y Z A B C 

NEPBM e:                                                Z N
OFPDO f:S I I B X A R U N D E G X D Z M M Q X Y A Y T F G B
PGPDO g:E U Z W C L G R B M Q K T C C G H V P T F A B X D H
QHPDO h:H U D X Z S P N O L Y V C T R E C G J S E A J L W T
RIPDO i:P M L J B R Y O M C V T N P Q P Y D M N T S C P U F
SJPDO j:E X V M N P X Q Y I I R F X Z Z G K G Z T C Y D V W
TKPDO k:Q I A F M V D U F C L Q J A G C Z A B B D K T I U E
ULPDO l:J Y W P O T P F G W L B X M M B D J V L F Q F Q W T
VMPDO m:P X D J K B X C N I F S C M G S T G B T O R E M T E
WNPDO n:K L H C C U P D Q X C P T F O B L M V Y Z R I R M V
XOPDO o:H D G G H V T F W Q R Q F H K H N L X Q J I T N C S
YPPDO p:G S N S E J Q W R B I U K V G T O U E T B W P L C J
ZQPDO q:Y C X Q T B P J D M U S I R O K Y M A D O B V U P Z
ARPDO r:M B K H V B

Friedman's note: Error in ... portion (of text).
- (From XOPQANY key to XOPQAZK), Friedman's decipherment: HEMISPHEREPREVENT, Cryptogram: WQRQFHKHNLXQJITNC.

Carl Ellison tells us that the key is NEPQAAL and not NEPPALL.

References

Machine Cryptography and Modern Cryptanalysis, by Cipher A. Deavours & Louis Kruh, Artech House Editor, 1985.
This book describes the challenge in detail and gives the text of the cryptograms.

Web Links

NSA - Friedman's Original Worksheets of Hebern Solution, 11 Nov 1936 - ID A4126886 - (PDF)
Note: The solution dates from 1924.