Section: OpenSSL (1SSL)
openssl genrsa [-out filename] [-passout arg] [-aes128] [-aes128] [-aes192] [-aes256] [-camellia128] [-camellia192] [-camellia256] [-aes192] [-aes256] [-camellia128] [-camellia192] [-camellia256] [-des] [-des3] [-idea] [-f4] [-3] [-rand file(s)] [-engine id] [numbits]
RSA private key generation essentially involves the generation of two prime numbers. When generating a private key various symbols will be output to indicate the progress of the generation. A . represents each number which has passed an initial sieve test, + means a number has passed a single round of the Miller-Rabin primality test. A newline means that the number has passed all the prime tests (the actual number depends on the key size).
A quirk of the prime generation algorithm is that it cannot generate small primes. Therefore the number of bits should not be less that 64. For typical private keys this will not matter because for security reasons they will be much larger (typically 1024 bits).
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