Ciphers

First off GPG stands for GNU Privacy Guard , and is a open source implementation of PGP. So what can you do with GPG , and why should we care? One common use of is to sign your messages, this way the receiver can verify it did in fact come from you, and that it hasn’t been altered. -----BEGIN PGP PUBLIC KEY BLOCK----- Version: SKS 1.1.4 Comment: Hostname: keyserver.ubuntu.com mQENBFJgLEgBCADcYnqxjoWIUoaRQEdvyIKu0g2UkTRRUidpkLhqqLCMmP4EQgB9EosoTUVn NiLyXrqpSUvD5RkOtzj4rHIn2trSey9D7pu++5u1x0hGTIaCxcbQMK6l+MhqwLdPshyEvTv/ b+aNUZSiES4azzbTNX06O0uUT3qQqAgkZsFA1tBY4Fcw6GavvgifWL83XNJADpKV72tXraVE mHGeQltwMUT/klzTeamjiN/C/+/3POz8ogH7PQ2JAtd5us4bl/zVLPoi/tLIs+rizxP7EGnJ aILVTDxj14gDzSMPsxuLpOKwxZP08w4rdmIil9iBqDlc6YhSiGr48EIZP6qEIYQyuQmNABEB AAG0IEplZmZyZXkgTmVzcyA8ZmxpcDM4N0BnbWFpbC5jb20+iQE+BBMBAgAoBQJSYCycAhsD BQkHhM4ABgsJCAcDAgYVCAIJCgsEFgIDAQIeAQIXgAAKCRAVgZxb+A0sKJBJB/oCr8/1rIvD /b+trpmmMcStYAT+K/U41bWpCbE6yOIh+ab7Dgh3l3QRM48rUVYbR0gwWE9q8eE/NRaHDBDq 2jYaOv7kZMJ5KTiU3svnq0qDlbuA5MTvEis6rr+iNy1ne2kxOoukSiAfU6dIkQuSHU0Dz5Ns 2bAu0YBwoxtanDntqAjEOOr/VOYJKBP1fUhd413O3WOKRIUciGneDihUM+TGyG50wFmE7J7x j8ydkYZDvLrDNxOVqFm5SxugLke8jkaiiPSTk/mlckHupkJHtAPlxeq69N7HQVT+/aCKzIty Se4dQqJFV6VhlQVjLS3QYKUStja1bZJeE3rIKjOjBY0+tCVKZWZmcmV5IE5lc3MgPGpuZXNz QGZsaXAtZWRlc2lnbi5jb20+iQE+BBMBAgAoBQJSYCxIAhsDBQkHhM4ABgsJCAcDAgYVCAIJ CgsEFgIDAQIeAQIXgAAKCRAVgZxb+A0sKPbHB/4sSHuZvEdt3KIkIj5RRnNRXgJ0PnImp5Gk PY4vxuokWndmJUTF8JnGmmdJqBhpQ/bzWHdm9xYUd6QJ6IzSBCcYarBF7h7XcjY8nFheJsyF jfRcm90RsIMjDNhKtwB9aChCznVBnVujwRafVnyuerzexpsIrE6McN2s8redDlR0WBx+LZwm fwzZ+qX7PjCRlFsoNy0nUqI33EYP0QAbx6PCPcTiDcou5UFuOEK70uZh/k2l2hBOajWJN9x1 6UQVfGuOmERVsD6dXiCbNs1C7pce0Rj7WFwolpBBeYk9g5OHLmBdlf9pta3gJXExEJWJPLTS euQtKkTdj5Pu2HKX7qxyuQENBFJgLEgBCADY1aF23k3eLLGghn0xugEPKNaG6Ve1lozmCWK9 RgkQVhx070ktG5iVkT7Zx3VMMG0M2g/Aas/l5XC6Z3Gx3Fm3U5TQ43pNnR2vea1yhA1LrahN PwqQcNld+mtJca2go5hcX0pTqcYBNVkHtn+cMQJNPdyE1bWCh77BH/oScWNrwJVljPBsJju+ Wg5cFzHyujCaYd+RW7hG5nKC6Bz5ldXvUyeEAWyEjvXNM7gSmsXTBOOuFzyK2F50j7rLAyEI IyDN16zAyqiHOaq+4NJBRxLJmvR5bwOtTCSdtQPMxusG54Qc65VbJalGs90B4F+okP3FtNWs MaQzshuo8yaQJ9H5ABEBAAGJASUEGAECAA8FAlJgLEgCGwwFCQeEzgAACgkQFYGcW/gNLCjN yAgAoLtLiEuoq/NAkcXgrJtykicbXgeDDrXwlCEOeMuChsfAJeExN3GV1rGomq0AGySGuxgH +U61OAfeKcCWNCS3Sr7AVPbeqgomy4DDwkf60nks7/SKVEaOxMbdBaCBbYBi8gQWGc+3VTHM s4m9135nfQhhh5e8yAF0YiOv8+b7K+uLjrh6ggYXhvXWMvhqT5xN3NatAasfHIgbRVg26VxN GXWg6urEppXCeeNFosPSZrCHfMs+ncQR0+at7OAcbp8E8wGVLslYDbZSz/YGK+jVcfqzLKj7 DtK57lyAxrc+EY7385PPHhd0Lf5tRufsPce/Q2s/ItQTaYBKXWq0s5sFhg== =pePB -----END PGP PUBLIC KEY BLOCK----- Using the above public key we can verify a signed message I wrote.

Well that title is odd, right? What I’m wanting to do here is demonstrate one way to generate random numbers using a seed . The requirement here is we need to test a number at any given time, this will be useful if we intend to use the process as a token of sort, think RSA SecureID . Anyways I wanted to make a implementation that used Python and didn’t cost me hundreds of dollars.

Frequency Analysis is the study of the frequency of letters or groups of letters in a cipher text. Using Python we can extract the count of letters, bigrams, and trigrams, lets have a look shall we: $ ./frequency.py --help usage: frequency.py [-h] [--letters] [--bigrams] [--trigrams] msg positional arguments: msg Message to count letters in optional arguments: -h, --help show this help message and exit --letters, -l Frequency of letters --bigrams, -b Frequency of bigrams --trigrams, -t Frequency of trigrams Lets go ahead and enter a simple sentence and do some testing: