The best replacement for cryptography is encryption.

The best alternatives to cryptography are rated as following:
★★★★★  encryption
★★★★  steganography
★★★★  cryptology
★★★  cryptanalysis
★  asymmetric cryptography
★  secret key cryptography
★  private key cryptography
  quantum cryptography
  public key cryptography
  secret-key cryptography

Your alternative for cryptography is not listed? Suggest!
Speaking about cryptography, one probably shouldn't forget about steganography.

Other search terms related to cryptography and their ratings are:
★★★★★ steganography
★★★ biometrics
You have in mind a companion for cryptography and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of cryptography in all years. Click on graph for more.
cryptography
encryption
steganography