Here are some tools which might be of some assistance for a fledgling cryptanalyst.

• Atbash
• Rotate and shift
• Frequency count
• Histograms of frequencies
• Monoalphabetic substitutions
• Vigenère ciphers
• ADFGVX substitution
• ADFGVX transposition
• Enigma
• DES

• Modular addition
• Modular exponentiation
• Discrete logarithm

• ASCII <--> binary
• binary/decimal/hex converter