# How To Read Encryption/Hashing Notation

This is very basic, but what I'm wondering is: I have a few notations of hashing/RSA encryption that I'm unsure of when reading.

PKE(PW, K) With PW representing a password, K representing a 128-bit string and PKE representing RSA, how would this be interpreted? Do I combine the string and password then encrypt that or something else?

Same goes for this, ssk = H(K,NB,NA), where ssk is a secret shared key, H is the SHA-1 algorithm, K is the same as above and NB and NA are random 128-bit strings.

I'm trying to code these in Python, and I am quite stuck with the theory behind it.

• It would be awesome to know where you extracted this information from. But the expression $PKE(PW, K)$ typically means to encrypt the plaintext $K$ with the private key $PW$, which in the context of RSA is $PW = (p, q, \varphi(n))$. Aug 28 at 14:18
• @Bean Guy: "encrypt the plaintext 𝐾 with the private key" is incorrect. In asymmetric encryption we want to encrypt with the public key, decrypt with the private key. In asymmetric cryptography we can also sign with the private key, but that's not encryption.
– fgrieu
Aug 28 at 16:28