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Document Document SHA256 SHA256 - - PowerPoint PPT Presentation
Document Document SHA256 SHA256 - - PowerPoint PPT Presentation
Document Document SHA256 SHA256 !$(@0 = !$(@0 !$(@0 (digest) (digest) (digest) Sign Verify K?WS0* (signature) (Modified) Document Document SHA256
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Document SHA256 Ç!”$£”(@0 (digest) Sign Ç!”$£”(@0 (digest) Document SHA256 Ç!”$£”(@0 (digest) Verify K?çW”S0* (signature)
=
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(Modified) Document SHA256 5M/”ò*G2 (digest) Sign 5M/”ò*G2 (digest) Document SHA256 Ç!”$£”(@0 (digest) Verify %d2|<D+ (signature)
≠
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+
Digital Certificate Name: Alice Address: via Galliera, 3 email: alice@unibo.it
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- ∙
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Digital Certificate Name: Alice Address: via Galliera, 3 email: alice@unibo.it X!çW”S0* (signature)
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Certificate Alice
sign
Certificate CA6
sign
Certificate CA5
sign
Certificate CA4
sign
Certificate CA3
sign
Certificate CA2
sign
Certificate CA1
sign
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Certificate Alice
sign
Certificate Dana
sign
Certificate Charlie
sign
Certificate Bob
sign
Certificate Frank
sign
Certificate Elon
sign
Certificate Gwen
sign
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+
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←
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Document SHA256 Ç!”$£”(@0 (digest) Sign Verify K?çW”S0* (signature)
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∙
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+
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Document SHA256 Ç!”$£”(@0 (digest) Sign Verify K?çW”S0* (signature) Digital Certificate Name: Alice
(signatu re)
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- ∙
∙ ∙
- ∙
∙
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1. 2. 3. 4. ∙
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1. 2. 3. 4. ∙
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1. 2. 3. 4. ∙
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Request timestamping to TSA
Digital Certificate
Name: Alice
CA signature
Digital Certificate
Name: TSA
Other CA signature
Document SHA256 Ç!”$£”(@0 (digest) Sign K?çW”S0* (signature) Document SHA256 Sign 9F\?’AH§ (digest) 2020-10-07T1 5:57:42+00:00 (timestamp) ò<+4&H1ì (signature) Return Timestamp + Signature
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Digital Certificate
Name: Alice
CA signature
Document K?çW”S0* (signature)
Alice Certificate
ò<+4&H1ì (signature)
TSA Certificate
2020-10-07T1 5:57:42+00:00 (timestamp)
Digital Certificate
Name: TSA
Other CA signature
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- ∙
∙
H(“tails”) H(“heads”)
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- H(“99”) -> i902And3òjam32sì34d
H(“1”) -> HD57cb4jiuKlo98hgf
. . .
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- H(“+39 399 9999999”) -> ò20bAnd3òjam32sazè2
H(“+39 300 0000000”) -> 1A57cb4X2uKlo98hgf
. . .
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∙ ∙ ∙
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Mirko Zichichi X1457cb4jiuKlo98hgf
Indirizzo Pubblico
(alphanumeric)
associato a
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- ∙
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