Non penso che openssl abbia il codice per generare chiavi RSA usando l'algoritmo che vuoi. Ma puoi usare qualsiasi software per generare i valori che devono essere codificati nella chiave privata, e quindi codificarli nel modo giusto in modo che openssl possa quindi usare la chiave per qualsiasi cosa (generare CSR, creare certificati autofirmati, essere un server TLS , essere un client TLs che utilizza certificati client, ecc.)
Il formato della chiave che devi fornire è specificato in PKCS # 1 [1] e include: n, e, d, p, q, d mod (p-1), d mod (q-1) e (inverso di q) mod p.
Osserva ciò che openssl produce quando genera una chiave privata:
openssl genpkey -algorithm RSA -out private_key.pem -pkeyopt rsa_keygen_bits:2048
Questo è ciò che c'è dentro:
openssl rsa -in private_key.pem -text -noout
Ecco come è codificato:
openssl asn1parse -inform pem -in private_key.pem
0:d=0 hl=4 l=1212 cons: SEQUENCE
4:d=1 hl=2 l= 1 prim: INTEGER :00
7:d=1 hl=2 l= 13 cons: SEQUENCE
9:d=2 hl=2 l= 9 prim: OBJECT :rsaEncryption
20:d=2 hl=2 l= 0 prim: NULL
22:d=1 hl=4 l=1190 prim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
openssl asn1parse -inform pem -in private_key.pem -strparse 22
0:d=0 hl=4 l=1186 cons: SEQUENCE
4:d=1 hl=2 l= 1 prim: INTEGER :00
7:d=1 hl=4 l= 257 prim: INTEGER :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
268:d=1 hl=2 l= 3 prim: INTEGER :010001
273:d=1 hl=4 l= 256 prim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
533:d=1 hl=3 l= 129 prim: INTEGER :F2AED36E57E843155C2CD3CACAC84FBFD94DDF13796F2F189109C5A6AC0D345BE1B7EC4CE903618DA045B49D47F24D762566BBEFA2E84E4A5BC10024A9E8964AB60F4B4E7E63948D341BB977E257A17B69AB509123E2A671200BA31E05D39E0F5A5EFF063A11918DEBEC7FD550D0729D5EDBBD466BC0D23D77942200D95901FF
665:d=1 hl=3 l= 129 prim: INTEGER :DA38E120A3738BB96FC20056186F0A0ED748609E05D50561D7EA2BE439094FF2439F9C03DC6E808F3AB280358D0651632C384C4AA4CE067F319B9426A8B804A3817410F914FF072FCA98024E66067FE572C8ECE5E4FE263BDECC8EDBB60060D0EFF17B1D21FA711E4F8C59D826FAB348595563DCFE41348500F45B310DECF65F
797:d=1 hl=3 l= 128 prim: INTEGER :2A71951CE956FFD48E88708A39290B799C41D850099EFE77A7763411506A06CC430FEDCE0DBABFA70B6EE585D47D763AC193D42EB72935F81F5003FC6592FE2616ED59D862967BF6AE34631DAA827505A69785C1BCAAF93D33C39545BCF323E3BF8479C9D7021798E0B83E2B4AB50A36A7CE7AAE044E76F6B5213D4934BA3275
928:d=1 hl=3 l= 128 prim: INTEGER :68BB15A8D16959ECA46B4A3807BFFAE6C6819105262D6748DF141EFE883524EE53701DB368AE8BFAB1A40B8E27E1995BEC5414A15A591A9B1ED6D91278B4E05D0C7B04CE563A535BA772AEE0AB6C812340A497B579E253BD361F9C8C6BDBE09B461CF206385176CAA248ECB1A57B7A61C5A60AA87C4A1507A43EA22977D27B27
1059:d=1 hl=3 l= 128 prim: INTEGER :6B36867417418016B3E567A514C904E0443C0F8BBABF361230BF8021FC8BE807EB7DA4A77EA72FAB4F12C54C541C97F6368D54D60078A4347942884DBF2240017E1F554A771BD373B949A9B320D1589A617B0E16EC2A61A2C8D6F91F892A436FC553EFD98F371BFD66BB466016E63A3297271EE058025324CB7A5B27A262F099
1 - link