Hierarchy of Cryptanalysis Data

There are six different classes of cryptanalysis data:

1. Ciphertext only. The cryptanalyst has only access to one or more ciphertexts.
2. Known plaintext. The cryptanalyst has access to ciphertexts of which one corresponds to a known plaintext.
3. Chosen plaintext. The cryptanalyst has access to ciphertexts of which one corresponds to a plaintext which he/she has chosen.
4. Adaptively chosen plaintext. The cryptanalyst has access to ciphertexts of which one corresponds to a plaintext which he/she has chosen in an interactive way.
5. Chosen ciphertext. The cryptanalyst has access to plaintexts of which one corresponds to a ciphertext which he/she has chosen.
6. Adaptively chosen ciphertext. The cryptanalyst has access to plaintexts of which one corresponds to a ciphertext which he/she has chosen in an interactive way.

Note that the classes of data are ordered so each class requires more cryptanalyst control than the previous classes, e.g. a chosen plaintext requires more control than a known plaintext.

References

L. R. Knudsen, M. J. B. Robshaw, The Block Cipher Companion. Springer, 2011.