Cryptogram solver

README.md

@@ -61,6 +61,12 @@ create-github-repo
 ---
 Usage: `create-github-repo NAME DESCRIPTION`
 
+cryptogram.py
+---
+Usage: `cryptogram.py "MIH WAIHXS TFBFL OF WHLRLTWFS QAFY WIKFIYF CLFECW MIH QTCA LFWRFJC, MIH WAIHXS FVRFJC TC."`
+
+Interactive cryptogram solver.
+
 decolorize
 ---
 Strips ANSI color codes out of a stream

cryptogram.py

@@ -0,0 +1,152 @@
+#!/usr/bin/env python3
+letters           = "abcdefghijklmnopqrstuvwxyz"
+english_frequency = "etaoinsrhldcumfpgwybvkxjqz"
+UNASSIGNED = "?"
+assignment = { x: UNASSIGNED for x in letters }
+ciphertext = ""
+
+def sort_by_frequency(x):
+    import collections
+    return [value for value,count in collections.Counter(x).most_common()]
+
+def print_clear():
+    print("\u001b[2J\u001b[H")
+def print_color(x, color="gray"):
+    COLORCODE = {
+        "black":  "\u001b[30m",
+        "gray":   "\u001b[30;1m", # "bright black"
+        "grey":   "\u001b[30;1m",
+        "red":    "\u001b[31m",
+        "green":  "\u001b[32m",
+        "yellow": "\u001b[33m",
+        "blue":   "\u001b[34m",
+        "magenta":"\u001b[35m",
+        "cyan":   "\u001b[36m",
+        "white":  "\u001b[37m",
+    }
+    print(COLORCODE[color], end='')
+    print(x, end='')
+    print("\u001b[0m", end='') # reset
+def print_newline():
+    print()
+
+def display(active_cipher=None):
+    print_clear()
+    print_color("substitution", "white")
+    print_newline()
+    for x in letters:
+        if x == active_cipher:
+            print_color(x, "blue")
+        elif assignment[x] == UNASSIGNED:
+            print_color(x)
+        else:
+            print_color(x, "green")
+    print_newline()
+    for x in letters:
+        if x == active_cipher:
+            print_color(x, "blue")
+        elif assignment[x] == UNASSIGNED:
+            print_color("?")
+        else:
+            print_color(assignment[x], "green")
+    print_newline()
+    print_newline()
+
+    print_color("frequency", "white")
+    print_newline()
+    ciphertext_frequency = "".join(sort_by_frequency([x for x in ciphertext.lower() if x in letters]))
+    for x in ciphertext_frequency:
+        if x == active_cipher:
+            print_color(x, "blue")
+        elif assignment[x] == UNASSIGNED:
+            print_color(x)
+        else:
+            print_color(x, "green")
+    print_newline()
+    for x in english_frequency:
+        count = len([y for y in letters if assignment[y] == x])
+        if active_cipher and x == assignment[active_cipher]:
+            print_color(x, "blue")
+        elif count > 1:
+            print_color(x, "red")
+        elif count == 1:
+            print_color(x, "green")
+        elif count == 0:
+            print_color(x)
+    print_newline()
+    print_newline()
+
+    print_color("cipher", "white")
+    print_newline()
+    for x in ciphertext:
+        if x.lower() not in letters:
+            print_color(x)
+        elif x.lower() == active_cipher:
+            print_color(x, "blue")
+        elif assignment[x.lower()] == UNASSIGNED:
+            print_color(x)
+        else:
+            print_color(x, "green")
+    print_newline()
+    for x in ciphertext:
+        if x.lower() not in letters:
+            print_color(x)
+            continue
+        if assignment[x.lower()] == UNASSIGNED:
+            plaintext = "?"
+        elif x in assignment and assignment[x] != UNASSIGNED:
+            plaintext = assignment[x]
+        else:
+            plaintext = assignment[x.lower()].upper()
+        count = len([y for y in letters if assignment[y] == assignment[x.lower()]])
+
+        if x.lower() == active_cipher:
+            print_color(plaintext, "blue")
+        elif plaintext == "?":
+            print_color("?")
+        elif count > 1:
+            print_color(plaintext, "red")  
+        else:
+            print_color(plaintext, "green")
+    print_newline()
+
+import sys, termios, tty
+def getch():
+    fd = sys.stdin.fileno()
+    old_settings = termios.tcgetattr(fd)
+    try:
+        tty.setraw(sys.stdin.fileno())
+        return sys.stdin.read(1)
+    finally:
+        termios.tcsetattr(fd, termios.TCSADRAIN, old_settings)
+def get_okch(ok, error):
+    while True:
+        c = getch().lower()
+        if c in ok:
+            return c
+        else:
+            print(repr(c), error)
+
+if __name__ == "__main__":
+    assert len(sys.argv) == 2
+    ciphertext = sys.argv[1]
+    while True:
+        display()
+        c = get_okch(ciphertext.lower() + "\r\x7f", "not in ciphertext, or enter (exit), or backspace (clear all)")
+        if c == "\r":
+            sys.exit(1)
+        elif c == "\x7f":
+            assignment = { x: UNASSIGNED for x in letters }
+            continue
+        display(c)
+
+        p = None
+        p = get_okch(letters + " \r\x7f", "not an english letter, space (clear), or enter (exit)")
+        if p == " " or p == "\x7f":
+            assignment[c] = UNASSIGNED
+        elif p == "\r":
+            sys.exit(1)
+        else:
+            assignment[c] = p
+
+