21 Cryptography

21.1 Pseudo-Random Sequences

Magma provides tools for the creation and analysis of pseudo-random bit sequences. The universe of these sequences is generally GF(2). However, some functions, such as Berlekamp-Massey, apply to sequences defined over arbitrary finite fields.

  • Generation of n elements of a Linear Feedback Shift Register sequence (LFSR sequence)

  • Next state of a LFSR sequence

  • Characteristic polynomial of a LFSR sequence (BerlekampMassey algorithm)

  • Shrinking generator

  • Random sequence via the RSA random bit generator

  • Random sequence via the Blum Blum Shub generator

  • Auto-correlation of a binary sequence

  • Cross correlation of two binary sequences

  • Decimation of a sequence