diff --git a/exercices/2018/leticia/core.clj b/exercices/2018/leticia/core.clj
new file mode 100644
index 0000000..b58fe7d
--- /dev/null
+++ b/exercices/2018/leticia/core.clj
@@ -0,0 +1,104 @@
+(ns cipher.core)
+
+
+
+
+(def encr1 "radyjgtxhpsncpbxrvtctgpaejgedhtegdvgpbbxcvapcvjpvtrdbqxcxcv
+iwtpeegdprwpqxaxinpcsxcitgprixktstktadebtciduphrgxeixcvapcvjp
+vtlxiwpctuuxrxtcipcsgdqjhixcugphigjrijgtudgbjaixiwgtpstsegdvg
+pbbxcvo")
+
+
+(defn to-int
+  [letra]
+  (- (int letra) (int \a)))
+
+(defn adicionar
+  [valor chave]
+  (+ valor chave))
+
+(defn novo-valor
+  [posicao]
+  (char (+ posicao (int \a))))
+
+(defn shift
+  [letra chave]
+  (-> (to-int letra)
+      (adicionar chave)
+      (mod 26)
+      novo-valor))
+
+(defn caesar-encrypt
+  "encriptando uma palavra w com uma chave k utilizanado a cifra de César"
+  [w k]
+  (apply str (mapv #(shift % k) w))
+  )
+
+(defn caesar-dencrypt
+  "decriptação uma palavra w com uma chave k utilizanado a cifra de César"
+  [w k]
+  (apply str (mapv #(shift % (- k)) w))
+  )
+
+
+(defn get-letters
+  [vstr]
+  (->> (filterv #(Character/isLetter %) vstr)
+      (apply str)
+      clojure.string/lower-case))
+
+(defn encriptar
+  [w k]
+  (-> (get-letters w)
+      (caesar-encrypt k)))
+
+(defn count-letters
+  [letra vstr]
+  (->> (filterv #(= % letra) vstr)
+       count))
+
+(defn to-char
+  [letra]
+  (char (+ letra (int \a))))
+
+(def alphabet (map to-char (range 26)))
+
+(defn contar-letras
+  [frase]
+  (->> (map #(count-letters % frase) alphabet)
+      (zipmap alphabet)))
+
+(defn ordenar-hashmap
+  [hashmap]
+  (sort-by second > hashmap))
+
+(defn get-tres-primeiros
+  [frase]
+  (->> (contar-letras frase)
+      (ordenar-hashmap)
+      (take 3)))
+
+(defn computar-chave
+  [c2 c1]
+  (- (int c2) (int c1)))
+
+(defn descriptografar
+  [frase letra]
+  (-> (get-tres-primeiros frase)
+      (nth 0)
+      (get 0)
+      (computar-chave letra)
+      (->> (caesar-dencrypt frase))))
+
+
+(defn encrypt-letter
+  [c1 c2]
+  (-> (+ (to-int c1) (to-int c2))
+      (mod 26)
+      novo-valor))
+
+(def cycle1 (cycle "cipher"))
+
+(defn encriptar-Vigenere
+  []
+  (mapv #()))
\ No newline at end of file
diff --git a/exercices/2018/leticia/core_test.clj b/exercices/2018/leticia/core_test.clj
new file mode 100644
index 0000000..7cf206e
--- /dev/null
+++ b/exercices/2018/leticia/core_test.clj
@@ -0,0 +1,94 @@
+(ns cipher.core-test
+  (:require [midje.sweet :refer :all]
+            [cipher.core :as core]))
+
+
+(def encr1 "radyjgtxhpsncpbxrvtctgpaejgedhtegdvgpbbxcvapcvjpvtrdbqxcxcv
+iwtpeegdprwpqxaxinpcsxcitgprixktstktadebtciduphrgxeixcvapcvjp
+vtlxiwpctuuxrxtcipcsgdqjhixcugphigjrijgtudgbjaixiwgtpstsegdvg
+pbbxcvo")
+
+
+(facts "to-int"
+        (core/to-int \c) => 2)
+
+(facts "adicionar"
+       (core/adicionar 23 3) => 26)
+
+(facts "mod"
+       (mod 26 26) => 0)
+
+(facts "shift"
+       (core/shift \a 3) => \d
+       (core/shift \b 20) => \v
+       (core/shift \x 3) => \a
+       (core/shift \d -3) => \a)
+
+(tabular
+       (fact "caesar-encrypt"
+             (core/caesar-encrypt ?w ?k) => ?expect)
+       ?w ?k ?expect
+       "apple" 20 "ujjfy"
+       "leticia" 3 "ohwlfld")
+
+(tabular
+  (fact "caesar-dencrypt"
+        (core/caesar-dencrypt ?w ?k) => ?expect)
+  ?w ?k ?expect
+  "ujjfy" 20 "apple"
+  "ohwlfld" 3 "leticia")
+
+(tabular
+  (fact "get-letters"
+        (core/get-letters ?w) => ?expect)
+  ?w ?expect
+  "Oii, funcionou!" "oiifuncionou")
+
+(tabular
+  (fact "encriptar"
+        (core/encriptar ?w ?k) => ?expect)
+  ?w ?k ?expect
+  "Hello, friend!" 5 "mjqqtkwnjsi")
+
+(tabular
+  (fact "count-letters"
+        (core/count-letters ?letra ?w) => ?expect)
+  ?letra ?w ?expect
+  \a "aadvark" 3
+  \x "aadvark" 0
+  \d "oiii" 0)
+
+(facts "to-char"
+       (core/to-char 0) => \a)
+
+(tabular
+  (fact "get-tres-primeiros"
+        (core/get-tres-primeiros ?w) => ?expect)
+  ?w ?expect
+  "aabbbc" '([\b 3] [\a 2] [\c 1])
+  encr1 '([\p 19] [\t 17] [\x 17]))
+
+(tabular
+  (fact "computar-chave"
+        (core/computar-chave ?a ?b) >= ?expect)
+  ?a ?b ?expect
+  \p \e 11
+  \p \t -4
+  \p \a 15)
+
+(tabular
+  (fact "descriptografar"
+        (core/descriptografar ?a ?b) >= ?expect)
+  ?a ?b ?expect
+  encr1 \e "xgjepmzdnvytivhdxbzizmvgkpmkjnzkmjbmvhhdibgvibpvbzxjhwdidibxoczvkkmjvxcvwdgdotviydiozmvxodqzyzqzgjkhziojavnxmdkodibgvibpvxbzrdocvizaadxdzioviymjwpnodiamvnompxopmzajmhpgodocmzvyzykmjbmxvhhdibu"
+  encr1 \t "vehcnkxbltwrgtfbvzxgxkteinkihlxikhzktffbgzetgzntzxvhfubgbgzvmaxtiikhtvatubebmrtgwbgmxktvmboxwxoxehifxgmhytlvkbimbgzetgzntvzxpbmatgxyybvbxgmtgwkhunlmbgyktlmknvmnkxyhkfnembmakxtwxwikhzkvtffbgzs"
+  encr1 \a "clojureisadynamicgeneralpurposeprogramminglanguagecombiningctheapproachabilityandinteractivedevelopmentofascriptinglanguacgewithanefficientandrobustinfrastructureformultithreadedprogrcammingz"
+  "ahixblmaxmabgzpbmayxtmaxklmatmixkvaxlbgmaxlhnetgwlbgzlmaxmngxpbmahnmmaxphkwltgwgxoxklmhiltmtee" \t "hopeisthethingwithfeathersthatperchesinthesoulandsingsthetunewithoutthewordsandneverstopsatall")
+
+
+(tabular
+  (fact "encrypt-letter"
+        (core/encrypt-letter ?a ?b) >= ?expect)
+  ?a ?b ?expect
+  \e \i \m
+  \u \i \c)