There is a maximum size of data to encrypt using RSA?

Tiago Queiroz contato at
Thu Aug 2 16:11:27 CEST 2012

I am trying to encrypt a block of 1249 bytes with RSA, but when I use
/gcry_sexp_build/ to build a s-expression to be encrypted the function
return an empty s-expression.

But when I use a smaller block of bytes (like 20 or 100)
/gcry_sexp_build/ works well....

To build a s-expression I am using this:

gcry_sexp_build(&raw_data, &errorff, "(data (flags pkcs1) (value %b))",

where / is a /unsigned char */ and /data_size/ is an integer with
the number of bytes in /

Am I doing something wrong? Or Libgcrypt can not manipulate this amount
of data.


Tiago de França Queiroz

Universidade Federal do ABC - UFABC
Bacharelando em Ciências e Tecnologia
Bacharelando em Ciências da Computação

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