This is the homepage of Cryptomni, an open source program which can encrypt and decrypt files using the one-time pad cipher. A key file is created using the cryptographically strong random number generator SecureRandom. If a key is truly random, kept secret, and never reused, this encryption algorithm can be proven to be unbreakable.

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Click here to download Cryptomni. Leave any comments or feature requests in the forum.

The one-time pad cipher encrypts a file by combining it with a random key. The key must be at least as large as the file to encrypt. A single key can be used to encrypt multiple files as long as no portion of the key is reused.

Usage scenario: Person A decides to leave on a trip and wants secure communication with person B. Before A leaves, he creates a 2MiB Cryptomni key and leaves a copy of it with B. Now A and B can send each other secure messages. Every time a message is sent the used portion of the key is deleted. The receiver can decrypt messages because his own copy of the key corresponds to the encrypted file being sent.