Monthly Archives: November 2015

Asmcodes: TEA block cipher

Introduction Tiny Encryption Algorithm was published in November 1994 by Cambridge computer scientists, David John Wheeler and Roger Needham TEA is not subject to any patents. This along with its simplicity made it attractive to various developers, particularly in the … Continue reading

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Asmcodes: MD5 Cryptographic Hash

Introduction The MD5 Message-Digest Algorithm published in 1992 by Ron Rivest was his successor to MD4 which I’ve discussed previously. Some security considerations for this algorithm are detailed in RFC 6151 published in 2011. It is undoubtedly the most famous … Continue reading

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Asmcodes: Blowfish block cipher

Introduction Blowfish is a 64-bit block symmetric cipher supporting keys up to 448-bits. It was designed and published in 1994 by American cryptgrapher Bruce Schneier and intended as a drop-in replacement for DES which many at the time suspected of … Continue reading

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Asmcodes: RC5 Block Cipher 32-bit

RC5 is a symmetric block cipher designed in 1994 by Ronald Rivest. It uses 128-bit keys, processes 64-bit blocks of data using 12 rounds of encryption/decryption. Key setup void rc5_setkey (RC5_CTX *key, void *input) { uint32_t i, j, k, A, … Continue reading

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Asmcodes: SHA-1 cryptographic hash

Introduction The Secure Hash Algorithm 1 (SHA-1) is a cryptographic hash function designed by the United States National Security Agency (NSA) and is a Federal Information Processing Standard (FIPS) published by United States National Institute of Standards and Technology (NIST) … Continue reading

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Asmcodes: MD4 cryptographic hash

Introduction The MD4 Message-Digest Algorithm RFC 1320 has been considered broken by the security community for well over a decade. RFC 6150 published in 2011 outlines the various reasons why it should cease being used so there’s no need to … Continue reading

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Asmcodes: SHA-256 cryptographic hash

Introduction SHA-2 (Secure Hash Algorithm) consists of 6 cryptographic hash functions designed by the NSA which were published in 2001 under royalty free patent. They are intended to be used for data integrity, message authentication and digital signatures. To avoid … Continue reading

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Asmcodes: Diffie Hellman and Modular Exponentiation

Introduction The Story Of Non-Secret Encryption published in 1997 by the now deceased J.H.Ellis documents early research by GCHQ employees into what we now refer to as PKC (Public Key Cryptography). Below is a list of papers/reports referenced by Ellis … Continue reading

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MD5 T and SHA-256 K Constants

Introduction During the process of optimizing MD5 and SHA-256, I wasn’t sure how much an impact it would have to generate the T and K constants during compression. Obviously it would be much slower but how much space could be … Continue reading

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Asmcodes: RC4 Stream cipher

Introduction RC4 is an infamous stream cipher designed in 1987 by Ron Rivest. It was an RSA trade secret up until September 1994 when an anonymous user posted source code to the cypherpunks mailing list Already used extensively in commercial … Continue reading

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