31 lines
584 B
Go
31 lines
584 B
Go
package psyfer
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//VigenereCipher performts vigenere on input
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func VigenereCipher(input string, key string, decrypt bool) string {
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alphabet := "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
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chars := []rune(input)
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k := []rune(key)
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keyPos := 0
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output := ""
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for _, m := range chars {
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index := int(m - 'A')
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offset := int(k[keyPos]-'A') % 26
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if decrypt {
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index -= offset
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} else {
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index += offset
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}
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if index >= 26 {
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index -= 26
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} else if index < 0 {
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index += 26
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}
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output += string(alphabet[index])
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keyPos++
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if keyPos == len(key) {
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keyPos = 0
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}
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}
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return output
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}
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