RSA encryption can only encrypt small amounts of data – True

Cryptosystem · Boneh · o@cs.stanford.edu · duction · cryptosystem, · Shamir, · Adleman · publicized · August · issue

This is highly improbable (only a proportion of 1/p + 1/q − 1/(pq) numbers have this property), but even in this case, the desired congruence is still true. Either m ≡ 0 (mod p) or m ≡ 0 (mod q), and these cases can be treated using the previous proof. There are a number of attacks against plain RSA as described below. When encrypting with low encryption exponents (e.g., e = 3) and small ...

$\begingroup$ This answer completely disregards the fact that in the question the message is encrypted using the private key. $\endgroup$ ... If your goal is to sign (authenticate) the data, and if RSA signatures are too long, there are some exotic schemes out there that have shorter signatures.

M message to be encrypted, an octet string of length mLen, where mLen <= k - 2hLen - 2 · or simply mLen = k - 2 * hLen - 2 if we want to calculate the maximum message size. ... The key size of RSA is defined as the number of bits within the ...

Thx $\endgroup$ ... $\begingroup$ If you encrypt data bigger than the modulus encryption will still produce output data, but that encrypted data will not decrypt to the correct initial data.

... RSA, as defined by PKCS#1, encrypts "messages" of limited size. With the commonly used "v1.5 padding" and a 2048-bit RSA key, the maximum size of data which can be encrypted with RSA is 245 bytes.

In other words, for a 1024-bit RSA key (128 bytes), up to 117 bytes. With OAEP (the PKCS#1 "new-style" padding), this is a bit less. OAEP uses a hash function with output length h bits; this implies a size limit of floor(n/8) - 2*ceil(h/8) - 2.

RSA does not encrypt raw data directly but applies a padding scheme to ensure security. Padding reduces the maximum size of the plaintext block. Padding Overhead: At least 11 bytes. Maximum Plaintext Size: Max Size = Key Size in Bytes – 11 · For a 2048-bit key: 256 – 11 = 245 bytes.