rsatool can be used to calculate RSA and RSA-CRT parameters
Python
1,677
33 commits
updated Jul 20, 2026
rsatool calculates RSA (p, q, n, d, e) and RSA-CRT (dP, dQ, qInv) parameters given either two primes (p, q) or modulus and private exponent (n, d).
Resulting parameters are displayed and can optionally be written as an OpenSSL compatible DER or PEM encoded RSA private key.
Supplying modulus and private exponent, PEM output to key.pem:
python rsatool.py -f PEM -o key.pem -n 13826123222358393307 -d 9793706120266356337
Supplying two primes, DER output to key.der:
python rsatool.py -f DER -o key.der -p 4184799299 -q 3303891593
1,232 followers · starred Aug 2016
2,389 followers · starred May 2015
776 followers · starred Mar 2016
1,115 followers · starred Oct 2017
rsatool can be used to calculate RSA and RSA-CRT parameters
Python
1,677
33 commits
updated Jul 20, 2026
rsatool calculates RSA (p, q, n, d, e) and RSA-CRT (dP, dQ, qInv) parameters given either two primes (p, q) or modulus and private exponent (n, d).
Resulting parameters are displayed and can optionally be written as an OpenSSL compatible DER or PEM encoded RSA private key.
Supplying modulus and private exponent, PEM output to key.pem:
python rsatool.py -f PEM -o key.pem -n 13826123222358393307 -d 9793706120266356337
Supplying two primes, DER output to key.der:
python rsatool.py -f DER -o key.der -p 4184799299 -q 3303891593
1,232 followers · starred Aug 2016
2,389 followers · starred May 2015
776 followers · starred Mar 2016
1,115 followers · starred Oct 2017