OpenSSL Public Key Cryptography

OpenSSL Shell commands

1. Generate Private key.

$openssl  genrsa  -out private.pem  1024

2. Extract Public key from Private key

$openssl rsa -in private.pem -pubout -out  public.pem

3. Sign using Private key [Encrypting using Private key]

$ openssl rsautl -sign -in file1.txt -inkey private.pem -out sig.txt

4. Verify using Public key [Decrypting using Public key]

$openssl rsautl -verify -in sig.txt -inkey public.pem -pubin -out sig2.txt

5. Encrypt using Public key

$openssl rsautl  -encrypt -inkey public.pem  -pubin -in file1.txt -out  file2.txt

6. Decrypt using Private key

$openssl rsautl  -decrypt -inkey private.pem  -in file2.txt -out  file3.txt

7. Create Message Digest

$openssl dgst -sign private.pem -out file.sign file1.txt

8. Verify Message Digest

$openssl dgst -verify public.pem -signature file.sign file1.txt

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