声明类型* big.Int溢出常量golang

Question

Generating a keypair using the crypto/rsa package is trivial, but declaring it yourself is a pain.

I'm trying to declare a variable of type rsa.PublicKey, which is defined as:

type PublicKey struct {
        N *big.Int // modulus
        E int      // public exponent
}

I've tried a hundred and three methods, but my code currently looks like:

PublicKey := new(rsa.PublicKey)

PublicKey.N = 816296297763124917516388440338759500423535395290623239231731567955308683122890408110917894172120047293936355563865250296188045077627313515614945465389856882915690164742049821466713295090362914686221827012330520911241180940331170800129566133563943306086709509374426793735798983196271063876215936717347200817820685489907456621846519078704338901417077754153251584919148131668369473222078960469749879767829241702858598298315759777245767370065542249841401685747514693845945420663931515035586797756896017462499826100826469085345198490755785708882569397123671313993933597159332140624225622926365258472081852103795720495728779491860405409429756519754432759030127289255409541378096471189783136441306888685144178712329637014132885623358066824356187044819578205172698506597932578231190886063535262514544569054747443504586895362356519252402500104155389876467086444850150261677007183689594568339805440756958346151465691221654766132846717117978938197863452998630570321897641091974200100764524637808876854013287571133384735164135339783262769321526997252096927500094807456840263828514476848496064212933462545940124330314474126636272733109787671957872657823289210871868354885730638093964892263227561606744192311648252923260065974092128743259979645799

PublicKey.E = 65537

I get this error:

./main.go:21: constant too large: 816296297763124917516388440338759500423535395290623239231731567955308683122890408110917894172120047293936355563865250296188045077627313515614945465389856882915690164742049821466713295090362914686221827012330520911241180940331170800129566133563943306086709509374426793735798983196271063876215936717347200817820685489907456621846519078704338901417077754153251584919148131668369473222078960469749879767829241702858598298315759777245767370065542249841401685747514693845945420663931515035586797756896017462499826100826469085345198490755785708882569397123671313993933597159332140624225622926365258472081852103795720495728779491860405409429756519754432759030127289255409541378096471189783136441306888685144178712329637014132885623358066824356187044819578205172698506597932578231190886063535262514544569054747443504586895362356519252402500104155389876467086444850150261677007183689594568339805440756958346151465691221654766132846717117978938197863452998630570321897641091974200100764524637808876854013287571133384735164135339783262769321526997252096927500094807456840263828514476848496064212933462545940124330314474126636272733109787671957872657823289210871868354885730638093964892263227561606744192311648252923260065974092128743259979645799
./main.go:21: overflow in constant
./main.go:21: cannot use 0 (type int) as type *big.Int in assignment

Any help?

Answer 1

The problem is that Go interprets your literal value as an int. But, it does not really fit into 32 bits, so it fails. However, you can set the value of a big.Int after its creation:

PublicKey.N = big.NewInt(0)
PublicKey.N.SetBytes([]byte("8162962977631249175163884403387595004235353952981629629776312491751638844033875950042353539529"))
fmt.Println(N)
// 8162962977631249175163884403387595004235353952981629629776312491751638844033875950042353539529