CRYPTOGRAPHY CRYPTOGRAPHY Krypts grphein secret writing CRYPTOGRAPHY Krypts

  • Slides: 69
Download presentation
CRYPTOGRAPHY

CRYPTOGRAPHY

CRYPTOGRAPHY “Kryptós” + “gráphein” secret writing

CRYPTOGRAPHY “Kryptós” + “gráphein” secret writing

CRYPTOGRAPHY “Kryptós” + “gráphein” secret writing Cryptography study of techniques for secure communication in

CRYPTOGRAPHY “Kryptós” + “gráphein” secret writing Cryptography study of techniques for secure communication in the presence of third parties (mostly called adversary)

CRYPTOGRAPHY “Kryptós” + “gráphein” secret writing Cryptography study of techniques for secure communication in

CRYPTOGRAPHY “Kryptós” + “gráphein” secret writing Cryptography study of techniques for secure communication in the presence of third parties (mostly called adversary) Cryptanalys study of methods for recovering the original text that has been encrypted without having access to the secret key

CRYPTOGRAPHY “Kryptós” + “gráphein” secret writing Cryptography study of techniques for secure communication in

CRYPTOGRAPHY “Kryptós” + “gráphein” secret writing Cryptography study of techniques for secure communication in the presence of third parties (mostly called adversary) Cryptanalys Cryptology study of methods for recovering the original text that has been encrypted without having access to the secret key

CRYPTOGRAPHY

CRYPTOGRAPHY

CRYPTOGRAPHY

CRYPTOGRAPHY

CRYPTOGRAPHY

CRYPTOGRAPHY

CRYPTOGRAPHY

CRYPTOGRAPHY

CRYPTOGRAPHY

CRYPTOGRAPHY

CRYPTOGRAPHY

CRYPTOGRAPHY

CRYPTOGRAPHY Secret Key ENCRYPTION ALGORITHM Ciphertext

CRYPTOGRAPHY Secret Key ENCRYPTION ALGORITHM Ciphertext

CRYPTOGRAPHY

CRYPTOGRAPHY

CRYPTOGRAPHY

CRYPTOGRAPHY

CRYPTOGRAPHY

CRYPTOGRAPHY

CRYPTOGRAPHY

CRYPTOGRAPHY

CRYPTOGRAPHY

CRYPTOGRAPHY

CRYPTOGRAPHY DECRYPTION ALGORITHM Secret Key

CRYPTOGRAPHY DECRYPTION ALGORITHM Secret Key

CRYPTOGRAPHY Same key for both sides DECRYPTION ALGORITHM Secret Key

CRYPTOGRAPHY Same key for both sides DECRYPTION ALGORITHM Secret Key

CRYPTOGRAPHY Same key for both sides SYMMETRIC ENCRYPTION DECRYPTION ALGORITHM Secret Key

CRYPTOGRAPHY Same key for both sides SYMMETRIC ENCRYPTION DECRYPTION ALGORITHM Secret Key

CRYPTOGRAPHY Same key for both sides SYMMETRIC ENCRYPTION M ENCRYPTION ALGORITHM SK M DECRYPTION

CRYPTOGRAPHY Same key for both sides SYMMETRIC ENCRYPTION M ENCRYPTION ALGORITHM SK M DECRYPTION ALGORITHM CT CT SK

Ceasar Cipher 3 3 plaintext CLEOPATRA

Ceasar Cipher 3 3 plaintext CLEOPATRA

Ceasar Cipher 3 3 plaintext CLEOPATRA secret key 3 +

Ceasar Cipher 3 3 plaintext CLEOPATRA secret key 3 +

Ceasar Cipher 3 3 plaintext CLEOPATRA secret key 3 shift 3 to the right

Ceasar Cipher 3 3 plaintext CLEOPATRA secret key 3 shift 3 to the right +

Ceasar Cipher 3 3 plaintext KLEOPATRA secret key 3 + shift 3 to the

Ceasar Cipher 3 3 plaintext KLEOPATRA secret key 3 + shift 3 to the right ciphertext NOHRSDWUD

Ceasar Cipher 3 3 NOHRSDWUD

Ceasar Cipher 3 3 NOHRSDWUD

Ceasar Cipher 3 NOHRSDWUD 3 ciphertext

Ceasar Cipher 3 NOHRSDWUD 3 ciphertext

Ceasar Cipher 3 3 NOHRSDWUD ciphertext 3 secret key -

Ceasar Cipher 3 3 NOHRSDWUD ciphertext 3 secret key -

Ceasar Cipher 3 3 NOHRSDWUD ciphertext 3 secret key - shift 3 to the

Ceasar Cipher 3 3 NOHRSDWUD ciphertext 3 secret key - shift 3 to the left

Ceasar Cipher 3 3 NOHRSDWUD ciphertext 3 secret key - shift 3 to the

Ceasar Cipher 3 3 NOHRSDWUD ciphertext 3 secret key - shift 3 to the left CLEOPATRA plaintext

Shift Cipher • The "boss of bosses" of the Sicilian Mafia, Bernardo Provenzano (Binnu

Shift Cipher • The "boss of bosses" of the Sicilian Mafia, Bernardo Provenzano (Binnu u tratturi – Binnu the tractor), used a modified form of the Caesar cipher to obscure "sensitive information" in notes left to either his family or underlings. C A R L E O N E

Shift Cipher A B C O P D E F G H Q R

Shift Cipher A B C O P D E F G H Q R S T U I V • The "boss of bosses" of the Sicilian Mafia, Bernardo Provenzano (Binnu u tratturi – Binnu the tractor), used a modified form of the Caesar cipher to obscure "sensitive information" in notes left to either his family or underlings. J K W X C A R L M Y N Z L E O N E

Shift Cipher A B C 0 1 2 D E F G H 3

Shift Cipher A B C 0 1 2 D E F G H 3 4 5 6 7 I 8 J K L M N 9 10 11 12 13 O P Q R S T U V W X Y Z 14 15 16 17 18 19 20 21 22 23 24 25 • The "boss of bosses" of the Sicilian Mafia, Bernardo Provenzano (Binnu u tratturi – Binnu the tractor), used a modified form of the Caesar cipher to obscure "sensitive information" in notes left to either his family or underlings. C A R L E O N E

Shift Cipher A B C 0 1 2 D E F G H 3

Shift Cipher A B C 0 1 2 D E F G H 3 4 5 6 7 I 8 J K L M N 9 10 11 12 13 O P Q R S T U V W X Y Z 14 15 16 17 18 19 20 21 22 23 24 25 • The "boss of bosses" of the Sicilian Mafia, Bernardo Provenzano (Binnu u tratturi – Binnu the tractor), used a modified form of the Caesar cipher to obscure "sensitive information" in notes left to either his family or underlings. C A R L E O N E 2 0 17 11 4 14 13 4

Shift Cipher A B C 0 1 2 D E F G H 3

Shift Cipher A B C 0 1 2 D E F G H 3 4 5 6 7 I 8 J K L M N 9 10 11 12 13 O P Q R S T U V W X Y Z 14 15 16 17 18 19 20 21 22 23 24 25 • The "boss of bosses" of the Sicilian Mafia, Bernardo Provenzano (Binnu u tratturi – Binnu the tractor), used a modified form of the Caesar cipher to obscure "sensitive information" in notes left to either his family or underlings. C A R L E O N E 2 0 17 11 4 14 13 4 + 3

Shift Cipher A B C 0 1 2 D E F G H 3

Shift Cipher A B C 0 1 2 D E F G H 3 4 5 6 7 I 8 J K L M N 9 10 11 12 13 O P Q R S T U V W X Y Z 14 15 16 17 18 19 20 21 22 23 24 25 • The "boss of bosses" of the Sicilian Mafia, Bernardo Provenzano (Binnu u tratturi – Binnu the tractor), used a modified form of the Caesar cipher to obscure "sensitive information" in notes left to either his family or underlings. ciphertext C A R L E O N E 2 0 17 11 4 14 13 4 + 3 5 3 20 14 7 17 16 7

Shift Cipher A B C 0 1 2 D E F G H 3

Shift Cipher A B C 0 1 2 D E F G H 3 4 5 6 7 I 8 J K L M N 9 10 11 12 13 O P Q R S T U V W X Y Z 14 15 16 17 18 19 20 21 22 23 24 25 C A R L E O N E 2 0 17 11 4 14 13 4 + 15 17 15 6 (15+17) mod 26 = 6

Shift Cipher A B C 0 1 2 D E F G H 3

Shift Cipher A B C 0 1 2 D E F G H 3 4 5 6 7 I 8 J K L M N 9 10 11 12 13 O P Q R S T U V W X Y Z 14 15 16 17 18 19 20 21 22 23 24 25 C A R L E O N E 2 0 17 11 4 14 13 4 + 15 17 15 6 0 (15+11) mod 26 = 0

Shift Cipher A B C 0 1 2 D E F G H 3

Shift Cipher A B C 0 1 2 D E F G H 3 4 5 6 7 I 8 J K L M N 9 10 11 12 13 O P Q R S T U V W X Y Z 14 15 16 17 18 19 20 21 22 23 24 25 C A R L E O N E 2 0 17 11 4 14 13 4 + 15 17 15 6 0 19 3 2 19

Shift Cipher A B C 0 1 2 D E F G H 3

Shift Cipher A B C 0 1 2 D E F G H 3 4 5 6 7 I 8 J K L M N 9 10 11 12 13 O P Q R S T U V W X Y Z 14 15 16 17 18 19 20 21 22 23 24 25 C A R L E O N E 2 0 17 11 4 14 13 4 + 15 17 15 6 0 19 3 2 19 R P G A T D C T ciphertext

Shift Cipher A B C 0 1 2 D E F G H 3

Shift Cipher A B C 0 1 2 D E F G H 3 4 5 6 7 I 8 J K L M N 9 10 11 12 13 O P Q R S T U V W X Y Z 14 15 16 17 18 19 20 21 22 23 24 25 C A R L E O N E 2 0 17 11 4 14 13 4 + 15 17 15 6 0 19 3 2 19 R P G A T D C T

Shift Cipher A B C 0 1 2 D E F G H 3

Shift Cipher A B C 0 1 2 D E F G H 3 4 5 6 7 I 8 J K L M N 9 10 11 12 13 O P Q R S T U V W X Y Z 14 15 16 17 18 19 20 21 22 23 24 25 C A R L E O N E 2 0 17 11 4 14 13 4 + 15 R P G A T D C T 17 15 6 0 19 3 2 19 15 17 15 6 0 19 3 2 19 R P G A T D C T 2 0 17 (6 -15) mod 26 = 17

Shift Cipher A B C 0 1 2 D E F G H 3

Shift Cipher A B C 0 1 2 D E F G H 3 4 5 6 7 I 8 J K L M N 9 10 11 12 13 O P Q R S T U V W X Y Z 14 15 16 17 18 19 20 21 22 23 24 25 C A R L E O N E 2 0 17 11 4 14 13 4 + 15 R P G A T D C T 17 15 6 0 19 3 2 19 15 17 15 6 0 19 3 2 19 R P G A T D C T 2 0 17 11 4 14 13 4

Shift Cipher A B C 0 1 2 D E F G H 3

Shift Cipher A B C 0 1 2 D E F G H 3 4 5 6 7 I 8 J K L M N 9 10 11 12 13 O P Q R S T U V W X Y Z 14 15 16 17 18 19 20 21 22 23 24 25 C A R L E O N E 2 0 17 11 4 14 13 4 + 15 R P G A T D C T 17 15 6 0 19 3 2 19 15 17 15 6 0 19 3 2 19 R P G A T D C T 2 0 17 11 4 14 13 4 C A R L E O N E plaintext

Shift Cipher A B C 0 1 2 D E F G H 3

Shift Cipher A B C 0 1 2 D E F G H 3 4 5 6 7 I 8 J K L M N 9 10 11 12 13 O P Q R S T U V W X Y Z 14 15 16 17 18 19 20 21 22 23 24 25 C A R L E O N E 2 0 17 11 4 14 13 4 + 15 R P G A T D C T 17 15 6 0 19 3 2 19 15 17 15 6 0 19 3 2 19 R P G A T D C T 2 0 17 11 4 14 13 4 C A R L E O N E Is it hard to break this cipher?

Shift Cipher A B C 0 1 2 D E F G H 3

Shift Cipher A B C 0 1 2 D E F G H 3 4 5 6 7 I 8 J K L M N 9 10 11 12 13 O P Q R S T U V W X Y Z 14 15 16 17 18 19 20 21 22 23 24 25 F D U O H R Q H Is it hard to break this cipher?

Shift Cipher A B C 0 1 2 D E F G H 3

Shift Cipher A B C 0 1 2 D E F G H 3 4 5 6 7 I 8 J K L M N 9 10 11 12 13 O P Q R S T U V W X Y Z 14 15 16 17 18 19 20 21 22 23 24 25 F D U O H R Q H 5 3 20 14 7 17 16 7 Is it hard to break this cipher?

Shift Cipher A B C 0 1 2 D E F G H 3

Shift Cipher A B C 0 1 2 D E F G H 3 4 5 6 7 I 8 J K L M N 9 10 11 12 13 O P Q R S T U V W X Y Z 14 15 16 17 18 19 20 21 22 23 24 25 F D U O H R Q H 5 3 20 14 7 17 16 7 1 Is it hard to break this cipher?

Shift Cipher A B C 0 1 2 D E F G H 3

Shift Cipher A B C 0 1 2 D E F G H 3 4 5 6 7 I 8 J K L M N 9 10 11 12 13 O P Q R S T U V W X Y Z 14 15 16 17 18 19 20 21 22 23 24 25 F D U O H R Q H 5 3 20 14 7 17 16 7 1 4 2 19 13 6 16 15 6 Is it hard to break this cipher?

Shift Cipher A B C 0 1 2 D E F G H 3

Shift Cipher A B C 0 1 2 D E F G H 3 4 5 6 7 I 8 J K L M N 9 10 11 12 13 O P Q R S T U V W X Y Z 14 15 16 17 18 19 20 21 22 23 24 25 F D U O H R Q H 5 3 20 14 7 17 16 7 1 4 2 19 13 6 16 15 6 E B T N G Q P G Is it hard to break this cipher?

Shift Cipher A B C 0 1 2 D E F G H 3

Shift Cipher A B C 0 1 2 D E F G H 3 4 5 6 7 I 8 J K L M N 9 10 11 12 13 O P Q R S T U V W X Y Z 14 15 16 17 18 19 20 21 22 23 24 25 F D U O H R Q H 5 3 20 14 7 17 16 7 2 3 1 18 12 5 15 14 5 D B S M F P O F Is it hard to break this cipher?

Shift Cipher A B C 0 1 2 D E F G H 3

Shift Cipher A B C 0 1 2 D E F G H 3 4 5 6 7 I 8 J K L M N 9 10 11 12 13 O P Q R S T U V W X Y Z 14 15 16 17 18 19 20 21 22 23 24 25 F D U O H R Q H 5 3 20 14 7 17 16 7 3 2 0 17 11 4 14 13 4 C A R L E O N E Is it hard to break this cipher?

Shift Cipher A B C 0 1 2 D E F G H 3

Shift Cipher A B C 0 1 2 D E F G H 3 4 5 6 7 I 8 J K L M N 9 10 11 12 13 O P Q R S T U V W X Y Z 14 15 16 17 18 19 20 21 22 23 24 25 F D U O H R Q H 5 3 20 14 7 17 16 7 3 2 0 17 11 4 14 13 4 C A R L E O N E Is it hard to break this cipher? at most 26 keys

Shift Cipher A B C 0 1 2 D E F G H 3

Shift Cipher A B C 0 1 2 D E F G H 3 4 5 6 7 I 8 J K L M N 9 10 11 12 13 O P Q R S T U V W X Y Z 14 15 16 17 18 19 20 21 22 23 24 25 F D U O H R Q H 5 3 20 14 7 17 16 7 3 In brute force, at most 26 tries 2 0 17 11 4 14 13 4 C A R L E O N E Is it hard to break this cipher? at most 26 keys

Substitution Cipher A B C E S J O P G W D E

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

Substitution Cipher A B C E S J O P G W D E

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

Substitution Cipher A B C E S J O P G W D E

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

Substitution Cipher A B C E S J O P G W D E

Substitution Cipher A B C E S J O P G W D E F G H T U O F A Q R B I S T K N U L I J K Z P V V H W Y L M D X X C CARLEONE JEIDUGQU plaintext ciphertext How to break this cipher? Y M Z R N Q

Substitution Cipher A B C E S J O P G W D E

Substitution Cipher A B C E S J O P G W D E F G H T U O F A Q R B I S T K N U L I J K Z P V V H W Y L M D X X C CARLEONE JEIDUGQU plaintext ciphertext How to break this cipher? the number of possible keys: 26! ≈ 4. 03 x 1026 ≈ 288 Y M Z R N Q

Substitution Cipher A B C E S J O P G W D E

Substitution Cipher A B C E S J O P G W D E F G H T U O F A Q R B I S T K N U L I J K Z P V V H W Y L M D X X C CARLEONE JEIDUGQU plaintext ciphertext Y M N Q Z R How to break this cipher? the number of possible keys: 26! ≈ 4. 03 x 1026 ≈ 288 frequency analysis

Substitution Cipher • The frequency analysis of English alphabet • The most common bigrams

Substitution Cipher • The frequency analysis of English alphabet • The most common bigrams : TH, HE, IN, EN, NT, RE, ER, AN, TI, ES • The most common trigrams : THE, AND, THA, ENT, ING, ION, TIO, FOR, NDE, HAS

Substitution Cipher « GFS WMY OG LGDVS MF SFNKYHOSU ESLLMRS, PC WS BFGW POL

Substitution Cipher « GFS WMY OG LGDVS MF SFNKYHOSU ESLLMRS, PC WS BFGW POL DMFRQMRS, PL OG CPFU M UPCCSKSFO HDMPFOSXO GC OIS LMES DMFRQMRS DGFR SFGQRI OG CPDD GFS LISSO GK LG, MFU OISF WS NGQFO OIS GNNQKKSFNSL GC SMNI DSOOSK. WS NMDD OIS EGLO CKSJQSFODY GNNQKKPFR DSOOSK OIS 'CPKLO', OIS FSXO EGLO GNNQKKPFR DSOOSK OIS 'LSNGFU' OIS CGDDGWPFR EGLO GNNQKKPFR DSOOSK OIS 'OIPKU', MFU LG GF, QFOPD WS MNNGQFO CGK MDD OIS UPCCSKSFO DSOOSKL PF OIS HDMPFOSXO LMEHDS. OISF WS DGGB MO OIS NPHISK OSXO WS WMFO OG LGDVS MFU WS MDLG NDMLLPCY POL LYEAGDL. WS CPFU OIS EGLO GNNQKKPFR LYEAGD MFU NIMFRS PO OG OIS CGKE GC OIS 'CPKLO' DSOOSK GC OIS HDMPFOSXO LMEHDS, OIS FSXO EGLO NGEEGF LYEAGD PL NIMFRSU OG OIS CGKE GC OIS 'LSNGFU' DSOOSK, MFU OIS CGDDGWPFR EGLO NGEEGF LYEAGD PL NIMFRSU OG OIS CGKE GC OIS 'OIPKU' DSOOSK, MFU LG GF, QFOPD WS MNNGQFO CGK MDD LYEAGDL GC OIS NKYHOGRKME WS WMFO OG LGDVS. »

Substitution Cipher • the frequency analysis of the text :

Substitution Cipher • the frequency analysis of the text :

Substitution Cipher • the frequency analysis of the text : • substitute S and

Substitution Cipher • the frequency analysis of the text : • substitute S and O with E and T, respectively

Substitution Cipher « GFe WMY t. G LGDVe MF e. FNKYHte. U Ee. LLMRe,

Substitution Cipher « GFe WMY t. G LGDVe MF e. FNKYHte. U Ee. LLMRe, PC We BFGW Pt. L DMFRQMRe, PL t. G CPFU M UPCCe. Ke. Ft HDMPFte. Xt GC t. Ie LMEe DMFRQMRe DGFR e. FGQRI t. G CPDD GFe LIeet GK LG, MFU t. Ie. F We NGQFt t. Ie GNNQKKe. FNe. L GC e. MNI Dette. K. We NMDD t. Ie EGLt CKe. JQe. Ft. DY GNNQKKPFR Dette. K t. Ie 'CPKLt', t. Ie Fe. Xt EGLt GNNQKKPFR Dette. K t. Ie 'Le. NGFU' t. Ie CGDDGWPFR EGLt GNNQKKPFR Dette. K t. Ie 't. IPKU', MFU LG GF, QFt. PD We MNNGQFt CGK MDD t. Ie UPCCe. Ke. Ft Dette. KL PF t. Ie HDMPFte. Xt LMEHDe. t. Ie. F We DGGB Mt t. Ie NPHIe. K te. Xt We WMFt t. G LGDVe MFU We MDLG NDMLLPCY Pt. L LYEAGDL. We CPFU t. Ie EGLt GNNQKKPFR LYEAGD MFU NIMFRe Pt t. G t. Ie CGKE GC t. Ie 'CPKLt' Dette. K GC t. Ie HDMPFte. Xt LMEHDe, t. Ie Fe. Xt EGLt NGEEGF LYEAGD PL NIMFRe. U t. G t. Ie CGKE GC t. Ie 'Le. NGFU' Dette. K, MFU t. Ie CGDDGWPFR EGLt NGEEGF LYEAGD PL NIMFRe. U t. G t. Ie CGKE GC t. Ie 't. IPKU' Dette. K, MFU LG GF, QFt. PD We MNNGQFt CGK MDD LYEAGDL GC t. Ie NKYHt. GRKME We WMFt t. G LGDVe. »

Substitution Cipher • The most common trigram in the text is TLE, which can

Substitution Cipher • The most common trigram in the text is TLE, which can be THE. So, substitute L with H.

Substitution Cipher • The most common trigram in the text is TLE, which can

Substitution Cipher • The most common trigram in the text is TLE, which can be THE. So, substitute L with H. • The next common in the text is G which could be A, I, or O The third word is t. G - only ‘to’ makes sense -

Substitution Cipher « o. Fe WMY to Lo. DVe MF e. FNKYHte. U Ee.

Substitution Cipher « o. Fe WMY to Lo. DVe MF e. FNKYHte. U Ee. LLMRe, PC We BFo. W Pt. L DMFRQMRe, PL to CPFU M UPCCe. Ke. Ft HDMPFte. Xt o. C the LMEe DMFRQMRe Do. FR e. Fo. QRh to CPDD o. Fe Lheet o. K Lo, MFU the. F We No. QFt the o. NNQKKe. FNe. L o. C e. MNh Dette. K. We NMDD the Eo. Lt CKe. JQe. Ft. DY o. NNQKKPFR Dette. K the 'CPKLt', the Fe. Xt Eo. Lt o. NNQKKPFR Dette. K the 'Le. No. FU' the Co. DDo. WPFR Eo. Lt o. NNQKKPFR Dette. K the 'th. PKU', MFU Lo o. F, QFt. PD We MNNo. QFt Co. K MDD the UPCCe. Ke. Ft Dette. KL PF the HDMPFte. Xt LMEHDe. the. F We Doo. B Mt the NPHhe. K te. Xt We WMFt to Lo. DVe MFU We MDLo NDMLLPCY Pt. L LYEAo. DL. We CPFU the Eo. Lt o. NNQKKPFR LYEAo. D MFU Nh. MFRe Pt to the Co. KE o. C the 'CPKLt' Dette. K o. C the HDMPFte. Xt LMEHDe, the Fe. Xt Eo. Lt No. EEo. F LYEAo. D PL Nh. MFRe. U to the Co. KE o. C the 'Le. No. FU' Dette. K, MFU the Co. DDo. WPFR Eo. Lt No. EEo. F LYEAo. D PL Nh. MFRe. U to the Co. KE o. C the 'th. PKU' Dette. K, MFU Lo o. F, QFt. PD We MNNo. QFt Co. K MDD LYEAo. DL o. C the NKYHto. RKME We WMFt to Lo. DVe. »

Substitution Cipher « one way to solve an encrypted message, if we know its

Substitution Cipher « one way to solve an encrypted message, if we know its language, is to find a different plaintext of the same language long enough to fill one sheet or so, and then we count the occurrences of each letter. we call the most frequently occurring letter the 'first', the next most occurring letter the 'second' the following most occurring letter the 'third', and so on, until we account for all the different letters in the plaintext sample. then we look at the cipher text we want to solve and we also classify its symbols. we find the most occurring symbol and change it to the form of the 'first' letter of the plaintext sample, the next most common symbol is changed to the form of the 'second' letter, and the following most common symbol is changed to the form of the 'third' letter, and so on, until we account for all symbols of the cryptogram we want to solve. »

Cryptography Basic Terminology Cryptography means secret writing EncryptionCryptography Basic Terminology Cryptography means secret writing Encryption
Cryptography 1 Cryptography Crypto graphy secret writing toCryptography 1 Cryptography Crypto graphy secret writing to
Hidden Writing TELEGRAM TOP SECRET To STUDEN SECRETHidden Writing TELEGRAM TOP SECRET To STUDEN SECRET
CRYPTOGRAPHY the code CRYPTOGRAPHY Some examples the secretCRYPTOGRAPHY the code CRYPTOGRAPHY Some examples the secret
Cryptography Part I Basic Terminology Cryptography means secretCryptography Part I Basic Terminology Cryptography means secret
Secret Writing Presented by Cindy Norris Cryptography CryptoSecret Writing Presented by Cindy Norris Cryptography Crypto
Cryptography Cryptanalysis Classics The Evolution of Secret WritingCryptography Cryptanalysis Classics The Evolution of Secret Writing
Cryptography Cryptanalysis Classics The Evolution of Secret WritingCryptography Cryptanalysis Classics The Evolution of Secret Writing
Basic Cryptogrphy Basics Cryptography secret writing Definition 8Basic Cryptogrphy Basics Cryptography secret writing Definition 8
PROTECTION DES SOURCES JOURNALISTIQUES Secret professionnel non SecretPROTECTION DES SOURCES JOURNALISTIQUES Secret professionnel non Secret
Secret Server proposal Secret Service Need Background ManySecret Server proposal Secret Service Need Background Many
Secret Sort Secret Sort What is the RuleSecret Sort Secret Sort What is the Rule
Top secret Secret Internal use only Public ProductTop secret Secret Internal use only Public Product
Top secret Secret Internal use only Public SystemTop secret Secret Internal use only Public System
Shhh Its a Trade Secret A Trade SecretShhh Its a Trade Secret A Trade Secret
Le Secret Rendu simple Le Secret Nous vivonsLe Secret Rendu simple Le Secret Nous vivons
Top secret Secret Internal use only Public HighTop secret Secret Internal use only Public High
Top secret Secret Internal use only Public 2Top secret Secret Internal use only Public 2
Top secret Secret Internal use only Public 5Top secret Secret Internal use only Public 5
Visual Secret Sharing Schemes for Plural Secret ImagesVisual Secret Sharing Schemes for Plural Secret Images
Top secret Secret Internal use only Public 2Top secret Secret Internal use only Public 2
The Secret of the Kingdom The secret ofThe Secret of the Kingdom The secret of
LE DROIT AU SECRET La valeur du secretLE DROIT AU SECRET La valeur du secret
Chapter 5 Secret Sharing Randomness Information hiding SecretChapter 5 Secret Sharing Randomness Information hiding Secret