Study for CPMCC (Certified Professional Modern Cryptographer & Cryptanalyst)
Here is some information to guide you what to study and prepare for the exam.
- Cryptography - Understanding how encryption works, symmetric vs asymmetric, encryption algorithms like AES, RSA, ECC and others, key lengths, secure random generators, basics of cryptanalysis, hashing algorithms, basics of encoding, format preserving, order preserving, AONT(All or nothing transform), steganography, end-to-end encryption, how signing works with asymmetric cryptography. Applied Cryptography book is also very good source.