From da76ca3a120c71b7590595cbfd54907467efb3a2 Mon Sep 17 00:00:00 2001
From: kanade <kanade@kumo.work>
Date: Fri, 1 Apr 2022 17:59:51 +0800
Subject: [PATCH] init

---
 .gitignore |   1 +
 README.md  |   1 +
 go.mod     |   3 ++
 rsa.go     | 126 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 131 insertions(+)
 create mode 100644 .gitignore
 create mode 100644 README.md
 create mode 100644 go.mod
 create mode 100644 rsa.go

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..723ef36
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+.idea
\ No newline at end of file
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..fd45240
--- /dev/null
+++ b/README.md
@@ -0,0 +1 @@
+### rsa工具包
\ No newline at end of file
diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..54d2905
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,3 @@
+module git.oa00.com/go/rsa
+
+go 1.17
diff --git a/rsa.go b/rsa.go
new file mode 100644
index 0000000..002204f
--- /dev/null
+++ b/rsa.go
@@ -0,0 +1,126 @@
+package rsa
+
+import (
+	"bytes"
+	"crypto"
+	"crypto/rand"
+	"crypto/rsa"
+	"crypto/sha1"
+	"crypto/x509"
+	"encoding/base64"
+	"fmt"
+)
+
+//Secret defines the private key type
+type Secret uint
+
+const (
+	PKCS1 Secret = iota
+	PKCS8
+)
+
+// SignWithSha1Base64 @Title 签名 采用sha1算法进行签名并输出为Base64格式
+func SignWithSha1Base64(data string, privateKey *rsa.PrivateKey) (string, error) {
+	h := sha1.New()
+	h.Write([]byte(data))
+	hash := h.Sum(nil)
+	signature, err := rsa.SignPKCS1v15(rand.Reader, privateKey, crypto.SHA1, hash[:])
+	if err != nil {
+		return "", err
+	}
+	out := base64.StdEncoding.EncodeToString(signature)
+	return out, nil
+}
+
+// EncryptWithSha1Base64 @Title 加密 采用sha1算法加密后转base64格式
+func EncryptWithSha1Base64(originalData string, publicKey *rsa.PublicKey) (string, error) {
+	partLen := publicKey.N.BitLen()/8 - 11
+	chunks := split([]byte(originalData), partLen)
+	buff := bytes.NewBufferString("")
+	for _, chunk := range chunks {
+		encryptedData, err := rsa.EncryptPKCS1v15(rand.Reader, publicKey, chunk)
+		if err != nil {
+			return "", err
+		}
+		buff.Write(encryptedData)
+	}
+	return base64.StdEncoding.EncodeToString(buff.Bytes()), nil
+}
+
+// DecryptWithSha1Base64 @Title 解密 对采用sha1算法加密后转base64格式的数据进行解密
+func DecryptWithSha1Base64(encryptedData string, privateKey *rsa.PrivateKey) (string, error) {
+	encryptedDecodeBytes, err := base64.StdEncoding.DecodeString(encryptedData)
+	if err != nil {
+		return "", err
+	}
+	partLen := privateKey.PublicKey.N.BitLen() / 8
+	chunks := split(encryptedDecodeBytes, partLen)
+	buffer := bytes.NewBufferString("")
+	for _, chunk := range chunks {
+		decrypted, err := rsa.DecryptPKCS1v15(rand.Reader, privateKey, chunk)
+		if err != nil {
+			return "", err
+		}
+		buffer.Write(decrypted)
+	}
+	return buffer.String(), err
+}
+
+func split(buf []byte, lim int) [][]byte {
+	var chunk []byte
+	chunks := make([][]byte, 0, len(buf)/lim+1)
+	for len(buf) >= lim {
+		chunk, buf = buf[:lim], buf[lim:]
+		chunks = append(chunks, chunk)
+	}
+	if len(buf) > 0 {
+		chunks = append(chunks, buf[:len(buf)])
+	}
+	return chunks
+}
+
+//ParsePrivateKey parses private key bytes to rsa privateKey
+func ParsePrivateKey(privateKeyDecoded string, keyType Secret) (*rsa.PrivateKey, error) {
+	decodeString, err := base64.StdEncoding.DecodeString(privateKeyDecoded)
+	if err != nil {
+		return nil, err
+	}
+	switch keyType {
+	case PKCS1:
+		return x509.ParsePKCS1PrivateKey(decodeString)
+	case PKCS8:
+		keyParsed, err := x509.ParsePKCS8PrivateKey(decodeString)
+		return keyParsed.(*rsa.PrivateKey), err
+	default:
+		return &rsa.PrivateKey{}, fmt.Errorf("secretInfo PrivateKeyDataType unsupport")
+	}
+}
+
+//ParsePublicKey parses public key bytes to rsa publicKey
+func ParsePublicKey(privateKeyDecoded string) (*rsa.PublicKey, error) {
+	decodeString, err := base64.StdEncoding.DecodeString(privateKeyDecoded)
+	if err != nil {
+		return nil, err
+	}
+	publicKey, err := x509.ParsePKIXPublicKey(decodeString)
+	if err != nil {
+		return nil, err
+	}
+	return publicKey.(*rsa.PublicKey), nil
+}
+
+// ParseCertificate 解析证书
+func ParseCertificate(certString string) (*x509.Certificate, error) {
+	decodeString, _ := base64.StdEncoding.DecodeString(certString)
+	return x509.ParseCertificate(decodeString)
+}
+
+// RsaEncrypt @Title Rsa加密
+func RsaEncrypt(origData []byte, publicKey *rsa.PublicKey) ([]byte, error) {
+	return rsa.EncryptPKCS1v15(rand.Reader, publicKey, origData)
+}
+
+// RsaDecrypt @Title Rsa解密
+func RsaDecrypt(ciphertext []byte, privateKey *rsa.PrivateKey) ([]byte, error) {
+	return rsa.DecryptPKCS1v15(rand.Reader, privateKey, ciphertext)
+}