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Ciphers
 

A cipher is a method by which a message can be encoded and decoded. Ciphers can be simple or complex depending on the amount and nature of cipher rules.

Ciphers have been used as early as 100 BCE by ancient Greeks as a way of encoding and decoding secret messages. The first recorded cipher was the Caesar Cipher. The cipher is a substitution cipher that involves replacing one letter for another and following the sequential alphabet until all other letters line up with their counterpart.

For example, 'Olssv!' is an encoded message using the Caesar cipher. However this message, and all others encoded with ciphers, are useless without a key. The key is the rule(s) you must follow in order to see the hidden message. In this case, the alphabet has been shifter 7 letters to the right (7a->h). Because of this, all instances of the letter 'a' become 'h', 'b' becomes 'i', etc.

Another popular substitution cipher is the keyword cipher. In this example a word acts as the key. The word is first written out with duplicate letters after the first instance removed. After the last letter, the alphabet is written out sequentially while also leaving out the letters appearing in the keyword. With this, you have your completed key that you can use to encode and decode messages.

 

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Spectogram
 

A spectrogram is a visual representation of the spectrum of frequencies in a signal as they vary with time. It's like a musical snapshot, capturing the different pitches and intensities of sound over a specific duration. The concept of a spectrogram dates back to the late 19th century when scientists and engineers began exploring ways to analyze and visualize sound. Over time, advancements in technology have made spectrograms more accessible and widely used.

Imagine you have a piece of music. A spectrogram breaks down this music into its individual frequencies and shows how loud each frequency is at any given moment.

• X-axis (horizontal): Represents time. As you move from left to right, you're progressing through the music or sound in chronological order.

• Y-axis (vertical): Represents frequency. The higher up you go, the higher the pitch of the sound.

• Color or intensity: Represents the amplitude or loudness of each frequency. Bright colors usually indicate louder sounds.

A spectrograph is an instrument that creates spectrograms. It's like a camera for sound, capturing the intricate details of a sound's frequency and amplitude. Over time, spectrographs have found applications in various scientific and engineering disciplines, including acoustics. Think of a spectrograph as a high-tech translator for sound. It takes the complex language of frequencies and turns it into a visual story.

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