Decrypt a monoalphabetic substitution cipher

A monoalphabetic substitution cipher applies a substitution table to the letters in the plaintext (often omitting all non-letters to disguise the word boundaries). For example, if the table is:

plaintext ABCDEFGHIJKLMNOPQRSTUVWXYZ ciphertext RDYBXZWFCTIELAMJPGQVNSOHUK 

Then the plaintext HELLO WORLD would be encrypted as FXEEMOMGEB.

Your program should take as input a ciphertext, for example:

UXLIRNXSOPQAKJBJTXSVTJKRHXKKJKLIQQOEBLXRSNJKWQKQKYSAQKLRVQNLJKQD QRPLJRSEWIRSWQWJHQKTRKKQRWIXSODXNXJSNJTLIQBRNLLIXNXNUIRLXYSAQKLR VQLJAJTJKEJYKQRAQK 

(together with advice from the cryptanalyst, if you wish) and output the plaintext.

Some more examples to test your code on (each is encrypted with a different cipher):

EVSXTTIWGVRMWIXWDXEMHWXDVCWGVSIKXWIRIQIVQFIVUUFIKGXEMLFVVMRVCFMW XTGIWFBZITGIWITGXEBEXEDVTGIWYVCETWDLIBTIZIWKVLIXCTBUCFTGIWIBKEVQ FXYIFBOIGVSI UZIRUKEJJXVMDKADJZXRYHSNOZENDNDKZXJDUIDJHJUAOAYIDUZIEUZNUKKXVOUA OXZKUSSTSDUKYJUGSDUZIHDZOUSEUIDMOKCUVDAMDXGBDVAOGDKASOLDIAXKDD EPOMQDHHXOHXKMOPKTQPNXTPEUCHKSDTUXDQDMDSDHNDQDOKMDQDMKXKQEADWYPK TPGNKAPRQXNXOTLWKQOCPEDKOTGXVVXTHPOHSPWHXXTLWXGPOHSXNXKQQXWAGXHN DOGXHEDHHKRQXH CYNCWRBNQNGNYPQANYPJQRCRBNCRBNSFYLQCCWRBNQNIBPXBPQRBNYFRJSFKGFYF YLIBPXBRBNQHPSPRIBCLNXPHBNSQRBNG 

Challenge entries

• Monoalphabetic Substitution Cipher (Python)
• Decrypting a substitution cipher using n-gram frequency analysis (Python)

Decrypt a monoalphabetic substitution cipher

A monoalphabetic substitution cipher applies a substitution table to the letters in the plaintext (often omitting all non-letters to disguise the word boundaries). For example, if the table is:

plaintext ABCDEFGHIJKLMNOPQRSTUVWXYZ ciphertext RDYBXZWFCTIELAMJPGQVNSOHUK 

Then the plaintext HELLO WORLD would be encrypted as FXEEMOMGEB.

Your program should take as input a ciphertext, for example:

UXLIRNXSOPQAKJBJTXSVTJKRHXKKJKLIQQOEBLXRSNJKWQKQKYSAQKLRVQNLJKQD QRPLJRSEWIRSWQWJHQKTRKKQRWIXSODXNXJSNJTLIQBRNLLIXNXNUIRLXYSAQKLR VQLJAJTJKEJYKQRAQK 

(together with advice from the cryptanalyst, if you wish) and output the plaintext.

Some more examples to test your code on (each is encrypted with a different cipher):

EVSXTTIWGVRMWIXWDXEMHWXDVCWGVSIKXWIRIQIVQFIVUUFIKGXEMLFVVMRVCFMW XTGIWFBZITGIWITGXEBEXEDVTGIWYVCETWDLIBTIZIWKVLIXCTBUCFTGIWIBKEVQ FXYIFBOIGVSI UZIRUKEJJXVMDKADJZXRYHSNOZENDNDKZXJDUIDJHJUAOAYIDUZIEUZNUKKXVOUA OXZKUSSTSDUKYJUGSDUZIHDZOUSEUIDMOKCUVDAMDXGBDVAOGDKASOLDIAXKDD EPOMQDHHXOHXKMOPKTQPNXTPEUCHKSDTUXDQDMDSDHNDQDOKMDQDMKXKQEADWYPK TPGNKAPRQXNXOTLWKQOCPEDKOTGXVVXTHPOHSPWHXXTLWXGPOHSXNXKQQXWAGXHN DOGXHEDHHKRQXH CYNCWRBNQNGNYPQANYPJQRCRBNCRBNSFYLQCCWRBNQNIBPXBPQRBNYFRJSFKGFYF YLIBPXBRBNQHPSPRIBCLNXPHBNSQRBNG 

Challenge entries

• Monoalphabetic Substitution Cipher (Python)
• Decrypting a substitution cipher using n-gram frequency analysis (Python)

Decrypt a monoalphabetic substitution cipher

A monoalphabetic substitution cipher applies a substitution table to the letters in the plaintext (often omitting all non-letters to disguise the word boundaries). For example, if the table is:

plaintext ABCDEFGHIJKLMNOPQRSTUVWXYZ ciphertext RDYBXZWFCTIELAMJPGQVNSOHUK 

Then the plaintext HELLO WORLD would be encrypted as FXEEMOMGEB.

Your program should take as input a ciphertext, for example:

UXLIRNXSOPQAKJBJTXSVTJKRHXKKJKLIQQOEBLXRSNJKWQKQKYSAQKLRVQNLJKQD QRPLJRSEWIRSWQWJHQKTRKKQRWIXSODXNXJSNJTLIQBRNLLIXNXNUIRLXYSAQKLR VQLJAJTJKEJYKQRAQK 

(together with advice from the cryptanalyst, if you wish) and output the plaintext.

Some more examples to test your code on (each is encrypted with a different cipher):

EVSXTTIWGVRMWIXWDXEMHWXDVCWGVSIKXWIRIQIVQFIVUUFIKGXEMLFVVMRVCFMW XTGIWFBZITGIWITGXEBEXEDVTGIWYVCETWDLIBTIZIWKVLIXCTBUCFTGIWIBKEVQ FXYIFBOIGVSI UZIRUKEJJXVMDKADJZXRYHSNOZENDNDKZXJDUIDJHJUAOAYIDUZIEUZNUKKXVOUA OXZKUSSTSDUKYJUGSDUZIHDZOUSEUIDMOKCUVDAMDXGBDVAOGDKASOLDIAXKDD EPOMQDHHXOHXKMOPKTQPNXTPEUCHKSDTUXDQDMDSDHNDQDOKMDQDMKXKQEADWYPK TPGNKAPRQXNXOTLWKQOCPEDKOTGXVVXTHPOHSPWHXXTLWXGPOHSXNXKQQXWAGXHN DOGXHEDHHKRQXH CYNCWRBNQNGNYPQANYPJQRCRBNCRBNSFYLQCCWRBNQNIBPXBPQRBNYFRJSFKGFYF YLIBPXBRBNQHPSPRIBCLNXPHBNSQRBNG 

Decrypt a monoalphabetic substitution cipher

A monoalphabetic substitution cipher applies a substitution table to the letters in the plaintext (often omitting all non-letters to disguise the word boundaries). For example, if the table is:

plaintext ABCDEFGHIJKLMNOPQRSTUVWXYZ ciphertext RDYBXZWFCTIELAMJPGQVNSOHUK 

Then the plaintext HELLO WORLD would be encrypted as FXEEMOMGEB.

Your program should take as input a ciphertext, for example:

UXLIRNXSOPQAKJBJTXSVTJKRHXKKJKLIQQOEBLXRSNJKWQKQKYSAQKLRVQNLJKQD QRPLJRSEWIRSWQWJHQKTRKKQRWIXSODXNXJSNJTLIQBRNLLIXNXNUIRLXYSAQKLR VQLJAJTJKEJYKQRAQK 

(together with advice from the cryptanalyst, if you wish) and output the plaintext.

Some more examples to test your code on (each is encrypted with a different cipher):

EVSXTTIWGVRMWIXWDXEMHWXDVCWGVSIKXWIRIQIVQFIVUUFIKGXEMLFVVMRVCFMW XTGIWFBZITGIWITGXEBEXEDVTGIWYVCETWDLIBTIZIWKVLIXCTBUCFTGIWIBKEVQ FXYIFBOIGVSI UZIRUKEJJXVMDKADJZXRYHSNOZENDNDKZXJDUIDJHJUAOAYIDUZIEUZNUKKXVOUA OXZKUSSTSDUKYJUGSDUZIHDZOUSEUIDMOKCUVDAMDXGBDVAOGDKASOLDIAXKDD EPOMQDHHXOHXKMOPKTQPNXTPEUCHKSDTUXDQDMDSDHNDQDOKMDQDMKXKQEADWYPK TPGNKAPRQXNXOTLWKQOCPEDKOTGXVVXTHPOHSPWHXXTLWXGPOHSXNXKQQXWAGXHN DOGXHEDHHKRQXH CYNCWRBNQNGNYPQANYPJQRCRBNCRBNSFYLQCCWRBNQNIBPXBPQRBNYFRJSFKGFYF YLIBPXBRBNQHPSPRIBCLNXPHBNSQRBNG 

Challenge entries

• Monoalphabetic Substitution Cipher (Python)
• Decrypting a substitution cipher using n-gram frequency analysis (Python)