转自：http://blog.****.net/duan19056/article/details/52104966
1、PKCS1私钥生成
openssl genrsa -out private.key 1024
private.key文件内容如下：
-----BEGIN RSA PRIVATE KEY-----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-----END RSA PRIVATE KEY-----
2、PKCS1私钥转换为PKCS8(该格式一般Java调用)
openssl pkcs8 -topk8 -inform PEM -in private.key -outform pem -nocrypt -out pkcs8.pem
pkcs8.pem文件内容
-----BEGIN PRIVATE KEY-----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-----END PRIVATE KEY-----
3、PKCS8格式私钥转换为PKCS1（传统私钥格式）
openssl pkcs8 -in pkcs8.pem -nocrypt -out pri_key.pem
pri_key.pem文件内容如下：
-----BEGIN RSA PRIVATE KEY-----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-----END RSA PRIVATE KEY-----