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Javascrypt [8] Free open-source text encryption tool runs entirely in web browser, send encrypted text over insecure e-mail or fax machine. PyEyeCrypt [9] Free open-source text encryption tool/GUI with user-selectable AES encryption methods and PBKDF2 iterations. Signal Protocol. Google Allo (optional) Facebook Messenger (optional) Signal ...
The KL-7, introduced in the mid-1950s, was the first U.S. cipher machine that was considered safe against known-plaintext attack. [8]: p.37 Classical ciphers are typically vulnerable to known-plaintext attack. For example, a Caesar cipher can be solved
Polygraphic substitution cipher: the unit of substitution is a sequence of two or more letters rather than just one (e.g., Playfair cipher) Transposition cipher: the ciphertext is a permutation of the plaintext (e.g., rail fence cipher) Historical ciphers are not generally used as a standalone encryption technique because they are quite easy to ...
Later Vula added a stream cipher keyed by book codes to solve this problem. [ 36 ] A related notion is the one-time code —a signal, used only once; e.g., "Alpha" for "mission completed", "Bravo" for "mission failed" or even "Torch" for " Allied invasion of French Northern Africa " [ 37 ] cannot be "decrypted" in any reasonable sense of the word.
Cipher detail; Key sizes: 128 bits: Block sizes: arbitrary, at least two words (64 bits) Structure: Unbalanced Feistel Network: Rounds: depends on the block size; ~52+6*words (6-32 full cycles) Best public cryptanalysis; XXTEA is vulnerable to a chosen-plaintext attack requiring 2 59 queries and negligible work. [1]
Stream ciphers are defined as using plain text digits that are combined with a pseudorandom cipher digit stream. Stream ciphers are typically faster than block ciphers and may have lower hardware complexity, but may be more susceptible to attacks.
An autokey cipher (also known as the autoclave cipher) is a cipher that incorporates the message (the plaintext) into the key. The key is generated from the message in some automated fashion, sometimes by selecting certain letters from the text or, more commonly, by adding a short primer key to the front of the message.
Cipher-block chaining (CBC) mode is an example of block cipher mode of operation. Some block cipher modes (CBC and PCBC essentially) for symmetric-key encryption algorithms require plain text input that is a multiple of the block size, so messages may have to be padded to bring them to this length.