1996 - 2000

• Helo Appel, Ingrid Biehl, Arnulph Fuhrmann, Markus Ruppert, Tsuyoshi Takagi, Akira Takura, Christian Valentin, "Ein sicherer robuster Zeitstempeldienst auf der Basis verteilter RSA-Signaturen", Systemsicherheit, ISBN3-528-05745-9, Vieweg, pp. 243-250, 2000. (In German) (ps)
• Michael Hartmann, Sachar Paulus, Tsuyoshi Takagi, "NICE - Ein neues Kryptosystem mit schneller Entschluesselung", Systemsicherheit, ISBN3-528-05745-9, Vieweg, pp. 93-104, 2000, (In German)
• Sachar Paulus, Tsuyoshi Takagi, "A New Public-key Cryptosystem over the Quadratic Order with Quadratic Decryption Time", Journal of Cryptology, 13, pp.263-272, 2000, Springer-Verlag. (pdf)
• Detlef Hühnlein, Tsuyoshi Takagi, "Reducing Logarithms in totally Non-Maximal Imaginary Quadratic Orders to Logarithms in Finite Fields", Advances in Cryptology - AISACRYPT '99, LNCS 1716, pp.219-231, 1999, © Springer-Verlag. (ps)
• Ingrid Biehl, Sachar Paulus, Tsuyoshi Takagi, "Efficient Undeniable Signature Schemes Based on Ideal Arithmetic in Quadratic Orders", Proceedings of Conference on the Mathematics of Public-Key Cryptography, Fields Institute for Research in the Mathematical Sciences, pp. 1-17, 1999. (ps)
• Michael Hartmann, Sachar Paulus, Tsuyoshi Takagi, "NICE - New Ideal Coset Encryption -", Workshop on Cryptographic Hardware and Embedded Systems (CHES), LNCS 1717, pp. 328-339, 1999, © Springer-Verlag. (ps)
• Detlef Hühnlein, Andreas Meyer, Tsuyoshi Takagi, "Rabin and RSA Analogues Based on Non-maximal Imaginary Quadratic Orders", 1998 International Conference on Information Security, ICISC'98, pp.221-240, 1999. (ps)
• Sachar Paulus, Tsuyoshi Takagi, "A Generalization of the Diffie-Hellman Problem and Related Cryptosystems Allowing Fast Decryption", 1998 International Conference on Information Security, ICISC'98, pp.211-220, 1998.
• Tsuyoshi Takagi, "Fast RSA-Type Cryptosystem Modulo pkq", Advances in Cryptology - CRYPTO '98, LNCS 1462, pp.318-326, 1998, © Springer-Verlag. (ps)
• Detlef Hühnlein, Michael Jacobson, Jr., Sachar Paulus, Tsuyoshi Takagi, "A Cryptosystem Based on Non-Maximal Imaginary Quadratic Orders with Fast Decryption", Advances in Cryptology - EUROCRYPT '98, LNCS 1403, pp.294-307, 1998, © Springer-Verlag. (ps)
• Tsuyoshi Takagi, Shozo Naito, "Construction of RSA Cryptosystem over the Algebraic Field Using Ideal Theory and Investigation of its Security", IEICE Transactions, Vol.J81-A, No.1, pp.119-128, 1998. (in Japanese) (pdf)
• Tsuyoshi Takagi, Shozo Naito, "Low Exponent Attacks against the Schwenk-Eisfeld Cryptoscheme and Signature", IEICE Transactions, Vol.E81-A, No.3, pp.483-488, 1998. (pdf)
• Tsuyoshi Takagi, "Fast RSA-Type Cryptosystems Using n-Adic Expansion", Advances in Cryptology - CRYPTO '97, LNCS 1294, pp.372-384, 1997, © Springer-Verlag. (ps)
• Tsuyoshi Takagi, Shozo Naito, "Extension of Rabin Cryptosystem to Eisenstein and Gauss Fields", IEICE Transactions, Vol.E80-A, No.4, pp.753-760, 1997. (pdf)
• Tsuyoshi Takagi, "Product Formula of the Cubic Gauss Sum Modulo the Product of the Primes", Journal of Number Theory, Vol.62, No.2, pp.298-306, 1997, © Academic Press. (pdf)
• Tsuyoshi Takagi, Shozo Naito, "The Multi-Variable Modular Polynomial and its Applications to Cryptography", 7th International Symposium on Algorithm and Computation, ISAAC'96, LNCS 1178, pp.386-396, 1996, © Springer-Verlag. (ps)