Solution of enciphered letter from 1645 – Prince Maurice writes to Lord George Digby

Staff of the British National Archives mentioned on their website the one very interesting letter from a very difficult times – English Civil War – when Parliamentarians and Royalists stood still against each other. The letter have been wrote by Prince Maurice of the Palatinate on the 31 August 1645, to the Lord George Digby. It contents was about military operations, scouting and information gathering on number of soldiers, morale and exact locations of the enemy units. Information about unsolved letter I got from Klaus Schmeh blog about other useful crypto stuff. As might see, character of used cipher – the “nomenclator” with nulls – not allowed use most know technique – simple frequency analysis of a single letters, bigrams, trigrams – in large scale, because in message  are also used codenames for common words and expressions, which make final solution as quite difficult. After several hours of effort using likely cribs (syllabes, words, places, etc.), by trial and error and checking if are the right ones, I finally conluded to the something, which could have been called “true meaning” of the letter. So check this out for yourself.

Nomenclator is a technique of secret writing, half cipher and half code. In direct translation from Latin this term simply means “name-caller”, thus referring to a codelist of names and was the primary means of masking communications. From about 1400 to 1850, beginning as a list of names with their equivalent codewords used by the scribes of popes and princes to protect personal and diplomatic correspondence, the nomenclator developed into a collection of syllabes, words and names similar to a code, with separate cipher alphabet. Also used were meaningless symbols called nihil importantes, or nulls, which were placed in the nomenclators to confuse would-be solution seekers (which I’m not:).

Consider, for example, this specimen:

A=01..05, B=06..10,…,Z=80..85, AND = 100, AT = 105 BE = 110, THE = 120, POPE = 250, KING = 300, COUNT = 350, DUKE = 400

Thus message: TO POPE, KING, A T T A C K  A T  D A W N becomes 60 50 250 300 01 62 63 03 15 33 04 64 18 01 70 38

Let’s look at Prince Maurice’s enciphered letter:

g1code

At first, I seek king Charles I. and Henrietta Maria’s ciphers. Background information about these methods of cryptography, has to be found at: http://cryptiana.web.fc2.com/code/charlesi.htm

I found later, that none of homophone or nomenclator ciphers is the right one. My solution for this letter was based on the similar characteristics like I found on website, mentioned above. The nomenclator used here seems typical of many I found in use during the Civil War in England 1642-45.

Great help is the fact that the letters and short words are arranged in sequences. There are a couple of places where substitution is likely wrong as in For d a b l e which is coded Null For d a e le (74 89 49 20 34 45 34), etc.

Finally it emerged, that such a nomenclator is solvable for sure, but much help also brought by “bad” habit of Prince Maurice not using it very well, for example very limited selection spread in the “e” sequence, over emphasis also on “98=he” and a bit slack in his NULL patterns to name just some.

Also interesting to note is, that given all the historical references, that the National Archives claimed not to know the content of the letter.

Enciphered portions of letter:

t he  r  e  t  u  r  n  e     u  f  t he  S  c  u  t  t  s horse
70 41 98 61 34 41 63 61 59 35 73 63 55 42 98 68 53 64 41 42 68 172

for d  a  e  l  e
74 89 49 20 34 45 34

t his  and    be  a w  d ly
70 41 99    79 70 83 20 1 50 110

i  t  u  s  e  l  e  s  s  e  to have  a  g  u  a  r  d     t here
8 41 15 68 34 45 34 68 69 34 125 94   20 47 16 21 61 49 73 41 96    70 76

but t he     yl  c  l  o  s  e  to  g  e  a  t he  r and have  a  b  o  v   e (1000)  horse
76 41 98 25 110 53 45 63 68 34 125 47 34 20 41 98 61 79   94   20 32 64 15 34         172

[together]
t he  y are        d  r  a w  in  g     a  f  t he  i  r  force  s
70 41 98 25 80  71 73 49 61 21 1 103 47 77 21 45 41 98  8 61  189   68

c  a  n  m  a  k  e for  t he     r  e  l  e i  f  e  u  f He  r  e  for  d
53 21 59 51 22 57 34 89  41 98 78 62 34 45 35 9 55 35 63 55 98 61 34 89   49 70

have  a  p  p  u i  n  t  e  d  t he i  r
94   21 43 44 63 8 59 41 34 49 41 98 8 62

of [rendezvous]  o  n  t  h i  r  s  day   l  a  s  t at
73      220     64 59 41 13 8 61 68   88  45 20 68 41 81

from  t  h  e  n  c  t  h ey are
90   41 98 59 54 37 42 98 28 80

d  to  m  u  v  e
70 49 125 51 63 15 35

i  ly and to  r  e  s  t  o  n  t  h  e  c  o  f i  n  e  s  o  f He  n  e for  d  s  h  i  r  e
8 110 79 125 61 35 69 41 67 60 42 98 54 64 59 55 9 60 36 68 66 56 98 60 34 89  50 68 13 10 61 34

ly   to  h  in  d  e  r  t he  S c   u  t  t  s from  t he  i  r for a  g  in  g
110 125 14 103 50 36 62 41 98 68 54 63 41 42 69 90   41 98 11 62 89 20 47 103 48

his  M  a j  e  s  t  i   e  s  d  e  s  i  g  n  e
70 99  51 20 9 34 69 41 25 34 69 50 36 68 12 48 59 38 70 76 77

….

Code for single letters and words:

1 w
8-12 i
13-14 h
15-18 u/v
20-22 a
25-28 y
32 b
34-38 e
41-42 t
43-44 p
45 l
47-48 g
49-50 d
53 c
54 c/b
55 f
57 k
59 n
60-62 r
63-68 o
68-69 s
70-78 Nulls (nihil importantes)
79 and
80 are
81 at
83 be
88 day
89 for
90 from
94 have
96 here
98 he
99 his
103 in
110 ly
125 to
172 horse
189 force
220 rendezvous

Frequency count:

70  – 9

41  – 21

98  – 15

61  – 9

34  – 17

63  – 7

59  – 7

35  – 3

73  – 3

55  – 4

42  – 5

53  – 3

64  – 4

68  – 10

172 – 2

74  – 1

89  – 3

49  – 4

20  – 8

45  – 6

99  – 2

83  – 1

1  – 2

50  – 3

110 – 3

8  – 6

15  – 3

69  – 5

125 – 5

94  – 3

47  – 4

16  – 1

21  – 5

96  – 1

76  – 3

25  – 3

45  – 5

79  – 2

32  – 1

80  – 2

71  – 1

103 – 3

77  – 2

189 – 1

51  – 3

22  – 1

57  – 1

78  – 1

62  – 4

9  – 3

43  – 1

44  – 1

220 – 1

13  – 2

88  – 1

90  – 2

54  – 3

37  – 1

28  – 1

110 – 2

67  – 1

60  – 2

36  – 3

66  – 1

56  – 1

10  – 1

14  – 1

103 – 1

11  – 1

48  – 2

12  – 1

38  – 1

81  – 1

Solution of letter, with  clear text as follows:

My Lord, — Your Lpp. of the 30 present came eaven now to my hands, wee heare not a word of
t he  r  e  t  u  r  n  e     u  f  t he  S  c  o  t  t  s horse
70 41 98 61 34 41 63 61 59 35 73 63 55 42 98 68 53 64 41 42 68 172

The bceing several places     for  d  a  e  l  e  betweene     t his  and     be  a w  d ley
74 89 49 20 34 45 34           70 41 99   79   70 83 20 1 50 110

I conceive i  t  u  s  e  l  e  s  s  e  to have  a  g  u  a  r  d the t here
8 41 15 68 34 45 34 68 69 34 125 94   20 47 16 21 61 49 73 41 96   70 76

The last Intelligence from the leagure before Hereford was that they resolved to assault the towne yesterday, since then, I have not heard anything but t he  y  ly  c  l  o  s  e  to  g  e  a  t he  r and have   a  b  o  v  e (1000) horse
76 41 98 25 110 53 45 63 68 34 125 47 34 20 41 98 61 79   94   20 32 64 15 34         172

My Lord Ashly certifyed mee the 23 present that 7 countyes are associated, and
[together]
t he  y are        d  r  a w  in  g     a  l  t he  i  r  force  s
70 41 98 25 80  71 73 49 61 21 1 103 47 77 21 45 41 98  8 61  189   68
those countyes  c  a  n  m  a  k  e for  t he     r  e  l  e i  f  e  u  f He  r  e for d
53 21 59 51 22 57 34 89  41 98 78 62 34 45 35 9 55 35 63 55 98 61 34 89 49 70

And in order to that have  a  p  p  u i  n  t  e  d  t he i  r
94   21 43 44 63 8 59 41 34 49 41 98 8 62

generall    [rendezvous]  o  n  t  h  i  r  s  day   l  a  s  t at
73      220     64 59 41 13  8 61 68   88  45 20 68 41 81 ;

Uak Abergaveny and Crickhowell, from  t  he  n  c  e  t he  y are
90   41 98 59 54 37 42 98 28 80
designe     d  to  m  u  v  e
70 49 125 51 63 15 35

speed i  ly and to  r  e  s  t  o  n  t he  c  o  n  f i  n  e  s  o  f He  n  e for  d  s  h  i  r  e
8 110 79 125 61 35 69 41 67 60 42 98 54 64 59 55 9 60 36 68 66 56 98 60 34 89  50 68 13 10 61 34

purpose ly   to  h  in  d  e  r  t he  S  c  u  t  t  s from  t he  i  r for a  g  in  g
110 125 14 103 50 36 62 41 98 68 54 63 41 42 69 90   41 98 11 62 89 20 47 103 48

I shall speedily acquaint my Lord Ashly with

    his M  a j  e  s  t  i  e  s  d  e  s  i  g  n  e
70  99 51 20 9 34 69 41 25 34 69 50 36 68 12 48 59 38 70 76 77

having not tyme to mention other perticulers. I rest yor. Lpps. very affectionate friend, Maurice. Worcester, 31 Aug., 11 a Clock.

(To be continued…)

Clear text of the letter, in full:

My Lord, — Yours of the 30th present came even now to my hands. We hear not a word of the return of the Scots’ horse. The[re] being several places fordable between this and Bewdley I conceive it useless to have a guard there. The last intelligence from the leaguer before Hereford was that they resolved to assault the town yesterday ; since then I have not heard anything, but they lie close together and have above 1,000 horse. My Lord Astley certified me the 23rd present that 7 counties are associated, and they are drawing [together] all the forces those counties can make for the relief of Hereford. And in order to that have appointed their general [rendezvous] on Thursday last at Usk, Abergavenny, and Crickhowell, from thence they are designed to move speedily and to rest on the confines of Herefordshire purposely to hinder the Scots from their foraging. I shall speedily acquaint my Lord Astley with his Majesty’s design, having not time to mention other particulars. I rest your Lordship’s very affectionate friend, Maurice. Worcester, 31 August, 11 o’clock.

Nevertheless, in discussion under Mr. Schmeh’s blog it has been found, that book of the official documents, entitled: “Calendar of State Papers, Domestic series, of the reign of Charles I 1645-1647″,  literally in Preface of book, on page ix, is that”The whole of the deciphered letters which are given in full in the Supplement to this Preface are written in the numerical cipher, and, as only brief notices of them could be given in the body of the work, they are here printed in their entirety ; the keys having been supplied through the kindness of Colonel J. S. Rothwell, R.A. to whose skill in this matter the historical student will for ever be indebted”. For me, whole surprise.

For information, images of enciphered letter and clear text from the book of British official papers:

First part of enciphered letter
Second part of enciphered letter
Official “clear text” of letter

So, first person, who are cryptanalyzed this one and also others enciphered letters was Colonel John Sutton Rothwell from The Royal Artillery.

According to Kent Ramliden, historical context of difficult military operations in English Civil War was:

“The retorne of the Scotts horse” likely refers to Major General David Leslie’s large (4000 horse) Scottish cavalry force which had been sent away from Hereford by the Covenanter commander Earl of Leven (Alexander Leslie) to deal with the Royalist Marquess of Montrose in Scotland. They did not return. (Both Leslies were extremely competent veterans of the 30-Year War in Germany btw).

The” fordable” places would be on the River Severn between “this=Worcester and Bewdley” to the northeast of Hereford. The mustering of troops from the “7 counties” at Usk, Abergavenny and Crickhowell would appear to refer to activities in Wales, well southwest of Hereford. These forces were then supposed to move NE into Herefordshire and at a minimum limit the foraging of the remaining Scottish cavalry which Prince Maurice estimates is still above 1000. What appears to be written “Lord Ashly” would in fact likely be “Lord Astley”, the King’s overall infantry commander.

Meanwhile King Charles left Oxford (to the southeast of Hereford) the day before, on August 30 with a force and marched toward Hereford. With the situation deteriorating up in Scotland, his main cavalry force already on his way there, and Royalists converging on Hereford, Earl Leven raised the siege, departed Herefordshire and headed up toward Scotland.King Charles entered Hereford on Sep 4. Still lost the war though.”

Many thanks to staff of British National Archives, Mr. Schmeh and Kent Ramliden. It was great opportunity, with small amount of work done, to link to the codebreaking giants like John Wallis, Francois Viete and Antoine Rossignol:)

Reklamy